Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Steam => Topic started by: DBS88 on August 16, 2024, 02:50:23 pm
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Quite unexpectedly I was offered the chance to buy a partially started model boat kit of a tug called Imara, it was an impulse buy, in the heat of the moment, literally I went out in the morning knowing nothing about the boat or model, and by lunchtime in the back of my car was a box of bits. I took it on as winter project, I asked my friend John to help with the build. Most of the parts for the kit were present, the hull had been fitted with prop shafts rudder, servo and decking. The model has a steam boiler and two vee twin steam engines. Our first decision has been to build the Imara Kit as Perseverance. After about a year Imara became Perseverance and spent the rest of her working life as Perseverance The first task was to obtain plans and instructions for the Imara Kit, they were obtained quickly from contacts in other clubs and here on the forum (Thank you Martin and Martin). For my sins I have never built a model boat before, I have renovated a couple and have some knowledge of model steam, so I am truly grateful to John for agreeing to work with me on this project. This is very much a learning exercise for both of us and we will share with you our dilemmas, mistakes and hopefully some successes as well. It's always a risk taking on a job that has been started by someone else, so our next decision was to undo some of the work and and start again. Here are photos of the model and the steam plant as it was when I collected it and lastly the real Perseverance to give you an idea of what we are aiming to achieve.
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Great purchase Dave, a nice project, you will I hope keep us with the restoration :-))
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I remember 15 or more years ago answering an add in Model boats mag for a steam plant, a cheddar boiler, ceramic burner, gas tank and 2 x twin cylinder puffin engines all tubed up in copper with the other necesarry plumbing ready to go.
So I drove over from blackpool to leeds and went with my £500 quid asking price and put it on the table for the gentleman as the thing was so beautiful to me that my eyes were nearly popping out on stalks. I put it all in a box and stood to go out when he said " just a minute, you have forgotten something".
He disappeared in to the next room and came back with a partly built but full kit of the Imara converted to the Perseverance with the closed wheelhouse, plonked it on the table and said, this is yours as it goes with the steam plant.
you never get that lucky in modelling more than once.
I did finish the model in the end and it won best in class at the Blackpool show around 2008/9 but at the time had never got the plant steaming although I did have it certificated for pressure safety. And at that same show a certain model kit manufacturer of modern lifeboats made a bid on the model and I left with two kits of his 12th scale lifeboats. A good deal considering what I had paid for it only months before.
I built boats faster in those days.........but your model just reminder me of it and what she would have looked like had I got her steaming.........wonder if the owner after our deal still has her.
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Phil and Neil, thank you for your kind feedback. The steam plant that came already installed in Perseverance comprises of Two Vee Twin double acting oscillating engines, PM Research No 8 Engines, each with a 1/2 inch bore ad 3/4 inch stroke. Each engine has a single control valve that selects forwards/reverse and controls the engine speed (these were not set to be used). The boiler that supplies the steam is a MacSteam 3 1/2 inch boiler, gas is supplied from a refillable MacSteam gas tank and the exhaust steam exits via a homemade oil separator then out via the chimney. When ehe steam plant was checked over and fired up, the boiler was fine and the engines turned over beautifully. so all positive. The problems with the existing layout are accessing the two engines to oil them, removing the steam plant to service it and the way the throttle was set up meant both engines operated at the same time and speed but only in forwards. The decision was therefore made to remove all the steam plant, increase the access space, then reinstall the steam plant on a new base board – more about this in later updates. Here are photos showing the engines and steam plant
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Bonjour Dave,Great project indeed :-))
Several remarks:
- These steam machines are 8 cm3 each ==> with this small boiler, you will have a small autonomy, a pump could be an option to increase it.
- Twin machines are great for manouverablity ==> I would kindly suggest you to install a servo for each of them, this means two inverters.
- I would kindly suggest you to install a safety gasvalve and a gas regulator.
And last but not the least, where is the whistle ok2 ?
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Twin machines are great for manouverablity ==> I would kindly suggest you to install a servo for each of them, this means two inverters.
Yes, you need independent engine control. I built the original review model for Model Boats magazine which was electrically propelled and it does not respond to the rudder. This is why a single screw version of the kit was subsequently offered.
Colin
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You are certainly going in at the deep end for a first model, I wish you all the luck. nemesis
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As an observation, as you are temporarily removing the steam plant my I counsel that you lag the boiler as this will reduce internal heat and make it a little more efficient. With an internal plant you will need a lot of ventilation so in the superstructure, every door, porthole, hatch etc should be open to admit air. It may also be a good idea to use a small computer fan to duct air into the boiler room, it does no harm. I have two models with internal installation and use a fan on both to assist.
Lovely looking miodel and great purchase.
Cheers
Geoff
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Also lag all the steam lines from the boiler to the engines to reduce condensation and reduction of steam pressure. I also assume you will remove the gas tank from the model to re-fill it as gas is havier than air and will ignite in the bildges.
Cheers
Geoff
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Thank you all for your feedback.
Raphael yes when I started I was concerned about the boiler being able to cope with both these large powerful engines, and yes they will be installed correctly, each with its own servo, so each engine can be independently controlled for speed, forwards and reverse. A radio controlled gas cut off valve will definitely be added, and when the model is proven I will consider the additions of a pump and a whistle.
Colin, you raise an interesting point about not responding to the rudder, I have heard that this can be an issue, depending on whether the props are turning into the centre of the boat, sucking the rear of the boat down, or the props turning outwards, so the rear of the boat rides on the prop wash, do you know which way the model was set up? I know very little about this and will have the props rotating inwards to start with.
Geoff, most definitely will lag the boiler, have not done this before, so will learn a lot from the experience, will also make sure that the hatches provide air and also a release for the heat and humidity, will look at lagging ht pipes and the gas tank will be removable.
When reviewing the steam plant multiple problems were identified so I disassembled the whole plant so that it can be reinstalled with in an improved layout that will take into account the points raised. In effect it will be a complete new installation, albeit with parts that have been previously used. Here is a link to a video of the steam plant running before I removed it.
https://youtu.be/BEllvAAbEaE?si=-AAMt_chMJxUTKib (https://youtu.be/BEllvAAbEaE?si=-AAMt_chMJxUTKib)
Other problems with the steam plant are as follows: there is not enough space to lubricate the engines, the steam plant is integrated into the boat, it is not removable. The gas burner boils the water in the water level, so a protective screen is necessary. The engines and boiler are all placed higher in the boat than necessary, so I will try to place them as low as possible, closer to the bottom of the boat. I'm afraid of having a higher weight, I know that the superstructure and accessories will have a lot of weight at the top, so I want heavy objects to be as low as possible to promote stability.
[size=78%].[/size]
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My review model was set up with the props turning outwards. Changing to inward turning might help with steering by directing the ahead thrust across the rudder more but you would have to experiment unless another member can comment on this.
Colin
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Bonjour Colin,
I asked myself the same question for my boats equipped with 2 propeller shafts so I went for a walk in ports and I noticed that the work boats were rather supra divergent (right propeller turning in the direction of the needles of a watch) while the speed boats were super convergent.
Example : https://youtu.be/CagA7tJTPrs (https://youtu.be/CagA7tJTPrs)
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It is never simple. But waterflow against an inclined rudder is certain to have a turning effect even if the model is at rest. If the waterflow is being pushed away from the rudder then the rudder will be less or non effective and will only work once the boat is moving forward.
You can see this with paddle steamers.The rudder only begins to take effect when the ship is in motion. When I was aboard ps Waverley in Portsmouth Harbour some years ago, the vessel needed a workboat pushing on the bow to turn the ship towards the harbour entrance as without that assistance the rudder would have not been sufficient to safely turn the ship round even in the full width of the harbour.
The best configurations tend to be models with single screws and rudder or twin screws and rudders.
Colin
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Bonjour Colin,
This is why having two independant machines / propellers is really helpful.
I also have paddle boats and one of them has one machine for each wheel : https://youtu.be/SnXPs3sGdN8 and https://youtu.be/qLmOZyA-yKQ
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Great feedback on the direction of rotation for the props, I suspect I will have to try both in and outwards rotation to find which works best for this model, unless someone with an Imara can confirm in or out rotation works best.
With the engines removed from the boat, I got a good look at them, I had not seen them before. Both engines were bolted to a piece of wood, I removed the engines for cleaning and checking. The engines are the PM Research No 8 V Twin Steam Engine which is an oscillating v twin engine with forward, reverse, and speed control capabilities via a single servo operated lever for radio control, so one servo controls Stop, Go Forward, Reverse and the engine speed in both directions. The engine has a cast bronze base and frames, oilite bronze sleeve bearings on the crank shaft and piston rod. The crank pin bearings are machined from solid bronze which run on a ground pin. It also has a precision ground stainless steel piston rod with O ring seals. The lightweight aluminum cylinders are hard anodized to give you long wear. The crankshaft is 3/16" diameter precision ground stainless steel. The steam inlet and outlet are both threaded 3/16-40. Bore 13mm - 1/2 inch Stroke 19mm - 3/4 inch Twin Cylinder Double Acting Height: 63 mm - 2-1/2 inches Width: 112mm - 4-1/2 inches Length: 80mm - 3-1/8 inches. These are powerful and potentially steam hungry engines.
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Bonjour David,
I have compared my PM Research machine to two other 8 cc and it is not consuming more steam than the others : https://youtu.be/Uw4GUNGqvME
It’s a very torquey machine with excellent value for money :-))
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Raphael, Thank you for the link to the video steam test of the engine.
Everyone has there own way of doing things and I have seen a large number of steam plant installations now, what seems to work well from a maintenance and testing perspective is to have the complete steam plant (engines, boiler, oil separator, gas tank, water tank, servos etc) all on a single base that can be lifted from the hull easily. This was not the case with this project, so decided to change the layout so that it would all go on one board and to also increase the area of the access so that the steam plant would lift in and out of the hull easily. The first step was to create a cardboard template upon which to test different layouts for the steam plant – as a result, the boiler has been turned round with the gas and oil separator tanks being placed side by side. The base board was then cut from waterproof ply and for the area where the engines would sit, a raised wall was created to confine water and steam oil residue, preventing it from running loose in the bottom of the hull. The board was painted with a heat resistant paint since the boiler will be operating at about 160C Here are some photos of the work in progress.
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Bonjour David,
Smart job indeed and unfortunately, not possible for all the boats, easy for an open launch but impossible for my cargos built originally for electric motors.
Steam purists used to say "a steam boat should be build around its plant, not the opposite" ok2
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Looking good. I would counsel you make the retaining walls on the engine bed plate higher as oscillating engines do make a mess!
Cheers
Geoff
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Geoff and Raphael, thank you both, I agree oscillating engines can be messy and it's not possible to build steam plants on removable trays for all models.
Having seen inside many models, it appears that modellers spend hours making the outside of their model look wonderful and less time on the areas that are not seen, so I will try to make the inside of this model as neat and tidy to look at as the outside. With the engine, boiler and other parts sat on the bench, the hull was basically empty so I washed the inside, dried it and sprayed it white with a heat and oil resistant paint. At the same time the deck openings were increased in size so that the whole steam plant can be removed by just disconnecting the prop shafts. My friend John made a neat job of cutting out the deck and making watertight doors that would open to allow the stream plant to be removed. However, between us, we made a mistake, we got the size of the opening and doors wrong, they were too small so the steam plant base caught the sides of the opening. I therefore cut the opening even bigger, we therefore needed another plan to cover the opening that was visible on the decking. Here are photos of the white inside with the first openings, the third photo shows the engines sat on the new baseboard together with the new bigger deck openings.
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Great feedback on the direction of rotation for the props, I suspect I will have to try both in and outwards rotation to find which works best for this model, unless someone with an Imara can confirm in or out rotation works best.
General thought in full size ship design is that outward turning props is best for manouvering, since both wheel effects are supposed to assist in the turn. Shape of the aftship has significant influence on how strong this effect is, but that is pretty unpredictable.
Inward turning props in ahead direction push the wake down and is claimed to have a better efficiency.
Converging or diverging propshafts also affect how the ship responds, where diverging shafts (props wider apart than the engines) reduces the turning effect of the props, and converging shafts increase this effect.
In general, anything that improves "long distance efficiency" (inward turning props, diverging shafts, single rudder) reduces manouverability and vice versa.
At least that is how it was taught to me in nautical college (quite a while ago), which admittedly was not an education in ship design...
For total disclosure, I have no idea how this would scale down to model size.
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For total disclosure, I have no idea how this would scale down to model size.
Good point, but all too often with models it is a case of 'suck it and see'.
You would think that modern full size propeller design might have been largely perfected by now but there is a report in the current issue of Ships Monthly magazine where fitting new propeller blades to a Baltic Ferry is expected to give a 13% increase in efficiency. Clearly there is still a lot to be learned.
If the full size version is still subject to so many variables, the model boating scene is even worse. Leaving aside the competitive model power boat racing where there is a lot of development, the scale side is much less clear. There is a vast range of propellers available but it remains very uncertain which one might be right for your boat. Most of them will work OK and for forward thrust any deficiencies can be overcome by a few more volts through the motor or opening the steam regulator a bit further. The loss of efficiency is not usually significant in the average sailing session. I found with one of my models that substituting a four blade prop for a three blade one gave a useful speed increase with negligible effect on sailing time. It was just more efficient.
When it comes to manoeuvrability there is no substitute for a model boat than directing the waterflow onto the rudder to kick the stern round. The alternative for twin screw boats is 'tank steering' whereby the motors are controlled independently but, although convenient for close quarters manoeuvrability, this can be quite a clumsy way of steering a boat around the pond. Mixers can sometimes offer a halfway house.
There is no need to overthink these things. For ahead thrust it doesn't much matter whether the props or inward or outward turning, but when it comes to steering (without tank steering) the key factor is the prop waterflow over the rudder(s) as it is this which determines steering characteristics.
Colin
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General thought in full size ship design is that outward turning props is best for manouvering, since both wheel effects are supposed to assist in the turn. S
That is why all British RNLI Lifeboats from the age of twin screws and indeed twin screw pilot boats have all been outward turning props on forward motion, giving them great manouvreability at the scene of a casualty.
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The discussion about the direction of turning for the props, with people being willing to share their experiences, shows the strength of a forum like this, thank you. So I guess now might be a good time to discuss props!
As this is a steam powered model, the slower the props turn, the less steam(water) is used and the longer the model can stay on the water. So with this in mind and with the knowledge that we are supplying steam to two large steam engines the decision to invest in two larger dia 4 blade steam props was made. The idea was to improve performance with two larger dia Propshop steam props to replace the props that came with the model. The 80mm props will help achieve the same speed with lower rpm and save steam, there by extending run times – at least thats the theory! The new props with 80mm dia and 1 to 1.5 pitch mean each revolution (in theory) moves the boat 120 mm through the water. The old props are 75mm dia and 1 to 1 pitch so one revolution moves the model 75mm. If nothing else, the new props look fabulous.
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i swear by Propshop gear............beautifully made and perfectly ballanced too. :-))
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Bonjour David,
I fully agree with you, steam means torque and allow pitched propellers.
Besides this, I also like very much Simons's propellers, have a lot of them and made a video about them : https://youtu.be/EN0drJGsdDo :-))
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i swear by Propshop gear............beautifully made and perfectly ballanced too. :-))
Me too - I do not think there is better out there
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I agree, the Propshop props are fabulous and have definatly improved the performance of other models that I have installed them on, Simon is very helpful.
Thank you for the advice received so far, decided to insulate the boiler. I first disassembled the boiler, then descaled and cleaned it. I had a thin insulating mat, so I cut it to measure and used PVA glue to hold it to the boiler. I chose to make the outer envelope that covers the insulation from a thin stainless steel sheet. I cut it with a guiletene and marked the location of the holes. I didn't have drills of the right size and it can be difficult to drill large holes in a thin sheet, so I used a small drill several times and a grinding wheel on my Dremel tool to open the holes. I made a mistake and damaged the finished side of the stainless steel, leaving deep scratches. I felt stupid and I was going to put the part in the scrap bin, however, I thought I would try to repair the damage. I started with a sheet of aluminum oxide 60 grit paper until the scratches are no longer visible. Then, used, papers 80, 160, 320, 600 and 1200 until I got a finish that I liked, not a mirror finish, but a smooth shine.
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As an experiment I used some high temperature paint on the ends of the boiler and on the boiler fittings. Once the paint had cured i placed the stainless steel wrapper around the boiler and secured it into position. I like the clean look so do not plan to use the traditional brass boiler bands. I then installed the boiler fittings.
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That's a mean looking boiler :D
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The paint is self priming, the first coat goes on, then after twenty minutes a second coat is applied. The paint flows nicely, it does not leave brush marks and has a high shine.
Whilst assembling the boiler I installed a new product from Dénes Designs. I have installed his simple low level warning device. Its a clever device that is not fooled by bubbles or rapid movement of the water, its designed not to give false alarms I have installed is because the steam plant is going in an enclosed tug, so the water level cannot be seen without removing the superstructure. The device will detect the low water level and will sound an audible alarm.Here is a link to a video of me testing the Dénes Design low water level warning system
https://youtu.be/L8vZdry2FCU?si=GVZdPir2rVtN_evz
Because I was concerned when I first ran the steam plant about flames escaping from the sides of the burner i have reduced the gas jet size down from a 10 to an 8. In addition I have created a stainless steel shield that is fitted between the burner and the sight glass. The aim is to stop any flames inpinging on the sight glass and also to protect the sensor .
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The engines were disassembled, cleaned, reassembled and painted along with other fittings. It was just as well because there were several loose bolts and the nut holding the seal for the piston rod was so loose that when the engine was rotated, the seal was sliding up and down about a 1/4 of an inch with the rod before hitting the nut and then returning to hit the underside of the cylinder. At first I thought the piston was broken, the movement was so strange. The piston and the cylinder bore were fine, the engines had hardly been run. The engines were well oiled as they were reassembled, they were then test run on air to rebid them in.
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A friend suggested adding a steam dryer to improve performance so a new chimney was created for the boiler. Instead of using 28mm pipe and fitting it inside the boiler flue exit I have used 35mm pipe fitted over the boiler flue exit. The external diameter of the pipe is 35mm and the internal diameter of the 35mm pipe is supposed to be 32mm. To make it fit snugly I made a ring from stainless steel sheet which took up the slack between the inside of the pipe and the outside of the boiler flue. I shaped the bottom of the pipe so that it was a good fit over the curve of the boiler casing. I then created a steam dryer and fitted that to the new chimney. Heres some photos which will give you a better idea than my description.
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Having received some advice the chimney has been modified. The steam dryer enters the chimney on one side and exits on the opposite side. When I looked at it again, I realized it would be better if the exit pipe was at 90 degrees to the entry pipe. This provides a central straight pipe run to the engines. I then cut slots in the chimney as advised to make it easy to remove
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excuse my ignorance, but what does a steam drier do?
cheers
Mike
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A quick description is that it superheats the steam, which has removed any moisture and increases the steam expansion :-))
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In general its not too wise to overheat the steam as we typically use displacement oil lubricatord. A small part of the steam condenses, sinks to the bottom and forces the oil into the steam line thus lubricating the engines. Just check to see how it goes.
From the original picture I notice the gas tank was just touching the boiler, or very close to. This is wise because as the liquid gas evspourates it changes state and needs energy to do this which it takes from the surrounding air, thus coolong the gas tank which in turn reduces the gas pressure and flame size etc. On my two steam models I have the end of the gas tank touching the oil seperator/condenser which works well. At the end of a run the gas tank is hand warm thus maintaining gas pressure and flame size.
Just in case this impacts your layout.
Cheers
Geoff
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In general its not too wise to overheat the steam as we typically use displacement oil lubricatord. A small part of the steam condenses, sinks to the bottom and forces the oil into the steam line thus lubricating the engines. Just check to see how it goes.
Cheers
Geoff
That is a misconception... The oiler forms a "dead end" and any steam entering that oiler WILL condense. No way around that. The steam needing to be "wet" for a displacement lubricator to work is a misconception: Water in steam cannot condense any further, so the moisture in steam has no incentive to enter the oiler. Dry steam will creep to places where it can condense, and the dead end of the oiler IS such a place.
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Mike, I too was unsure what a steam dryer did and this was not helped because whilst the terms steam dryer and superheater have specific meanings, they are also as terms wrongly used interchangeably and also they are misunderstood. Following advice from this forum my understanding is for the majority of our small steam engines (not high performance racing steam engines) in model boats all we need to do is to raise the temperature of the steam a little to increase its energy and to reduce the amount that turns back to water. The subject of steam, dry steam and superheated steam is vast with complex tables of temperature and pressure, so [size=78%]I was advised to watch this video by Kieth Appleton that gives a basic understanding. https://youtu.be/WzK0PJ6soxs?si=VDErNhlcfgvd_Gzl[/size]
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Having painted the engines and reassembled them the next task was to bolt them down to the base plate. I had purchased two stainless steel drive shafts with universal joints at each end. I realised that the base plate needed to be moved further towards the back of the boat, this meant the drive shafts were now too long. The board had to be moved further towards the back to allow the board to be slid towards the front of the boat when removing it from the boat. I therefore cut 2 cm from the hollow shaft only to find that the splined section was only on the end. I had to cut the hollow section off and then re attache the splined section, I used a smaller dia brass pipe and JB Weld epoxy glue to make the repair. I then cut down the splined part of the drive shaft. Since I had some stainless steel left from wrapping the boiler the decision was made to also cover the engine and boiler mounting board in stainless steel. Here are the engines and drive shafts being test fitted on the stainless steel covered board in the boat.
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Mike, I too was unsure what a steam dryer did and this was not helped because whilst the terms steam dryer and superheater have specific meanings, they are also as terms wrongly used interchangeably and also they are misunderstood. Following advice from this forum my understanding is for the majority of our small steam engines (not high performance racing steam engines) in model boats all we need to do is to raise the temperature of the steam a little to increase its energy and to reduce the amount that turns back to water. The subject of steam, dry steam and superheated steam is vast with complex tables of temperature and pressure, so [size=78%]I was advised to watch this video by Kieth Appleton that gives a basic understanding. https://youtu.be/WzK0PJ6soxs?si=VDErNhlcfgvd_Gzl (https://youtu.be/WzK0PJ6soxs?si=VDErNhlcfgvd_Gzl)[/size]
That is correct... but the worst of it, is that wet steam simply increases the waterconsumption of the boiler: for a given power output X, waterconsumption increases with the saturation percentage, because only steam excerts labour, water doesn't.
So a steam dryer/superheater just reduces water consumption, and always is a good idea.
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Previously we had a brief discussion about props, their size and direction of rotation, I came across this diagram today that I found useful in describing the effects of prop rotation, so here it is, hopefully you too find it of interest.
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The PM Research engines are fitted with a rotary steam valve that selects both forwards and reverse as well as acting as the throttle to increase and decrease the rpm. When I purchased the boat, these valves were not connected and were not being used. The way it was set up bothcengines went forwards at the same speed, no reverse and no independent control of each engine.
To use the valves the way they are intended, I needed to install two servo's. For this I cut and folded some aluminium sheet that I had removed from the boat. I painted the brackets to match the other items. Originally I planned for the servos to be installed between the two engines so they were partially hidden by the engines. I soon realised that with the servos close to each other, if one engine engine was put in forwards and the other in reverse the potential existed for the servo arms to hit each other. To avoid this mistake the servos were positioned outside each engine.
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Previously we had a brief discussion about props, their size and direction of rotation, I came across this diagram today that I found useful in describing the effects of prop rotation, so here it is, hopefully you too find it of interest.
That effect is, as a matter of "duh" depending on the angle of installation of the propshaft, but more even by the shape of the hull in the stern area: Even if the shaft is perfectly horizontal, if the hull shape causes an upward vector on the water inflow towards the prop, that effect will also exist.
I have sailed on ships with an asymetric aftship, that intended to counteract this effect as much as possible. It was always a bit of a surrealistic sight entering the shaft tunnel to inspect the seals: the whole thing looked a bit like an M.C. Escher drawing...
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That effect is, as a matter of "duh" depending on the angle of installation of the propshaft, but more even by the shape of the hull in the stern area: Even if the shaft is perfectly horizontal, if the hull shape causes an upward vector on the water inflow towards the prop, that effect will also exist.
I have sailed on ships with an asymetric aftship, that intended to counteract this effect as much as possible. It was always a bit of a surrealistic sight entering the shaft tunnel to inspect the seals: the whole thing looked a bit like an M.C. Escher drawing...
Please keep in mind: Those engines will radiate a fair bit of heat, as well as expell quite a bit of humidity. I don't know if it is wise to install servos that close to the engines in an enclosed hull.
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Thank you for the advice re the servo location. The boiler was firmly bolted to the base board, then the next task was to install the gas line. This includes lengths of pipe to join the gas tank, a rc operated gas cut off valve, a Bix gas attenuator (it came with the boat) and the burner. I bent to shape and cut to length the pipe, silver soldered the fittings, cleaned the pipes and assembled the gas line and attenuator to the burner.
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That is some seriously neat&tidy work!
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Bonjour David,
I have a RC gas valve like the one I see there and it leaks, so I did not install it, did you test yours ?
I really fear gas leaks and had a fire in one of my boats because of the RC gas valve itself ! https://youtu.be/DNTjVqbhezs
Besides this, great job indeed :-))
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Thank you for the kind words and support.
Raphael, sorry to hear that you had a problem with a gas leak and fire in one of your steam plants. Gas leaks in our models is always a risk, so great care is needed. I did test the gas line and the gas valves both with soapy water and also a lighter just to be sure, and no leaks were detected.
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Next task was to cut, bend and silver solder the steam pipes from the steam dryer to the lubricator and then to the engines. The pipes were then cleaned and assembled. The whole steam plant was then placed in the hull to check it all fitted when the deck housing was added.
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Looking really good Dave and a nice installation :-))
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At the beginning I said I would tell you what didn't go so well - so here's the beginning of a frustrating saga that will take a few posts to complete. - When I fired the boiler and brought it up to pressure the engines ran well. When I set the gas attenuator I did notice that with the engines running the attenuator was not responding as I expected so I decided to change the pipework so that the attuator was more direct to the boiler and that the engines were not on the same outlet from the boiler. I also confess that a couple of the silver soldered joints also leaked. I then reassembled the steam plant with the new pipework for the attenuator and the re soldered pipes to the steam dryer. Heres the revised pipework
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Frustrating time spent in the workshop is still better than a good day at work. I spent considerable time burning my fingers and doubting my engineering abilties. I had changed the piping for the steam supply to the gas attenuator, and used a four way fitting in the boiler outlet for the pressure gauge and the steam pipe for the attenuator, leaving one spare outlet. When I fired up the boiler, I noticed two issues, the first was a leak that appeared to come from the washers above and below pressure guage banjo fitting. The second was the presuure guage was not rising, initially I thought this was because of the steam leak. As I disassembled the pressure guage fitting I found the banjo was locked to the bolt, the bolt would not rotate without hte banjo as a result the pipe to the guage snapped off. Next I found the banjo was blocked with sealant, obviously I had used too much locktite and the excess found its way to places it should not have.
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You could also use a normal cone and nut for the pressure gauge in your application. Makes things easier to build than a banjo fitting.
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Thank you for the suggestion of using a different fitting for the syphon. I was lucky and had a spare syphon tube and banjo fitting so installed that only to find that there was a leak around the banjo fitting. I couldnt wait for the boiler to cool so worked on it whilst hot and redid the joint with new washers, again the same problem. I remade the joint numerous times and still it leaked even with thread sealant. Then I realised that the fitting itself was leaking via a crack or blow hole. I replaced the now broken fitting and reassembled the steam pipe to the attenuator and to the pressure guage and it all worked. The last photo shows the new configuration of the pipework.
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Nice :-)
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For interest and science, I heated the broken fitting up so that it was glowing red hot, the solder did not run, when it was cold I tried filing the solder, it, it was very hard, I therefore believe the fitting was silver soldered. All the pipework joints that I have soldered have also been silver soldered.
I test ran the boiler and when it was up and running, and making good steam, the engines ran nicely. Then I encountered the third problem of the weekend, the sound from the burner changed from a gentle sound to a louder roar. It was a sound I recognised from another incident on my boat Formidable. I turned off the gas and disassemebled the pipe to the burner. With the burner on the bench, it was clear to see the cracks in the ceramic insert, a test burn confirmed an unstable flame and the roaring noise as the burner destroyed itself.
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Fortunately I had some ceramic board left over from repairing the burner to my Hemmens model of Formidable. The burner for Perserverance is a MacSteam burner that came with the MacSteam boiler, I belive the boiler maker used had good quality materials and that the ceramic cracked maybe due to age? The cracked ceramic was removed and a new ceramic insert was cut using a hole saw. The insert was then sealed into position and left overnight to cure. When tested the burner performed well with a nice blue flame. A second test was done using the pipework installed for the boat with the burner horizontal.
I read that some ceramic boards can melt so I checked the replacement ceramic matt that I use to repair burners, I used my blow torch with MAPP Gas, which burns hotter than the propane butane mix, here is a photo - the replacement ceramic matt does not melt.
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Impress burner! :o
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Beautiful work. It is a joy to watch the progress.
What do you use to seal the ceramic board?
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The ceramic material was sealed into the burner head using fire cement that came in a tube. The old burner cracking was worrying me. Having thought about what was happening prior to its failure, the leaking steam fitting was above the burner and water did drip onto the burner whilst it was alight, maybe the thermal shock was enough to damage the ceramic. Also concerning was the thought that the material used might not have been good. So with those thoughts in mind I tested some of the broken pieces from the original ceramic burner. I palced the pieces on a heat resistant matt and used my MAPP Gas blow torch. The pieces of ceramic glowed and the heat matt got so hot it melted! The ceramic remained intact and did not melt so good news there was nothing wrong with the ceramic and the probable cause of the failure was water getting onto the hot ceramic. First photo is a small section of the old burner glowing. the second photo is the same section of burner after it had cooled, as you can see its structure has not melted or deformed.
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Here is a link to a video of the steam plant running after the repairs. The plant runs well and will be adjusted after a few more test runs to allow the engines to bed themselves in after they have been reassembled.
https://youtu.be/-rXseq8Mt1A?si=orjdvQ5F08rb5wsA
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I was given an airbrush for my birthday and wanted to learn how to use one. Previously all I have painted with an airbrush is a small Airfix Spitfire that I did at Christmas. The Perseverance kit came with some moulded resin/fibreglass cabins, these were my chance to get the airbrush out and practice some painting techniques, the first one I wanted to experiment with is pre shading, to enhance the joints and rivets on the cabins and to try and create some light and shade rather than a flat uniform colour, to try and make the cabin more interesting visually and hopefully more realistic? This is cabin as moulded, with a bit of rubbing down, some filler, then the presiding and next a first coat of white primer. I am just having a go at this after watching a few videos, so I could be doing this all wrong, but I am learning as I go.
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The colours to paint this model were researched and here are some photos of Royal Navy Dockyard Tugs and the colours used, these then inspired my choice.
After pre shading and priming I applied the finished colour. The research revealed a colour scheme for Royal Navy Dockyard Tugs, that the upper structures were Buff and the metal decking should be Olive Green. After a couple of coats of Buff it was apparent that my filling and preparation work were not good enough, so I rubbed down some more, applied a different filler, Mr Surfacer 500, and rubbed down again. I then touched in the newly filled areas with a brush – it looked a mess. Then applied two more coats of Buff with my airbrush. The desired result is something that looks a bit weathered, is realistic and visually more interesting that a solid flat colour. Whether I have succeeded will be a matter of opinion – should I have applied another coat of buff? do the plate joints and rivets standout too much?
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The funnel needed to be painted and research suggested that it should be buff, with the top black and with a blue band separated from the black top by a buff band. The whole of the funnel was primed light grey and then shaded in the rivets and panel edges to give some contrast. The funnel was sprayed with several coats of buff until I was happy with the colour and the shading. Then with masking tape I covered the buff above and below where the blue band was going. The blue paint was unbranded cheap airbrush paint which I brushed on, it took quite a few coats to build the depth of colour, so to speed things along I used a hair drier to dry the acrylic paint. With the blue done and dry, the bottom edge of the black was masked to achieve a nice crisp line and the airbrush was used to spray the top of the funnel with matt black.
Now here are the mistakes made.
1) For the Blue, the paint crept or was driven under the masking tape by the hair dryer in a few places, very disappointing.
2) When spraying the top of the funnel there was a band of masking tape that I thought would be sufficiently wide to prevent overspray going onto the buff areas of the funnel – wrong, very wrong.
3) When the masking tape was removed, the masked buff area of the funnel was a different colour buff than the area below the masking tape, not only due to the black overspray, but it would appear that the masking tape glue and hot air from the hair dryer may also have affected the colour.
It looked a mess, so I walked away, took time out, to work out the best way of saving the funnel.
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Having walked away from the funnel, frustrated with my stupid mistake, I remembered some advice about mistakes, its not always necessary to start over again, its about using the mistake and making the most of it. Since the decision was to go for a used/weathered look and this was a coal fired steam boiler powered boat, it's likely that the original boat was soot spattered and smoke stained. So decided to spray from a distance a fine mist of black paint over the funnel to add more spotting to hopefully make the most of the mistake and disguise the problem with the overspray – the worst that could happen was that I would need to repaint the whole funnel, so I went for it. Heres the result, what I have noticed is that issues are more noticeable in the photos than they are when you see the item for real. The tricky bit is about knowing when to stop, how far to go – hopefully this is ok – if not it's easier to add more soot spotting than it is to take it off.
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For the Hull I washed it clean and prepared it for painting, then applied some white primer. I used the plans to find the water line and transfered the water line to the hull. I then applied a narrow strip of masking tape over the white primer - the paint below this narrow strip would become the water line.
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For the Hull I continued to experiment, I wanted the plating to stand out, so again I pre-shaded the plate joints, but also, shaded some of the plates, so some would be darker than others, to try and add realism. I then applied several thin coats of the hull red colour until the desired effect was achieved.
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For the top of the hull I repeated the same process but made a mistake in the choice of black. I also added a blue line to the top of the hull, since the Blue was used to indicate the role of the tug when used in harbour. The black was too black, so the shading didnt show up, there was no shadow created.
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With the large parts of the model painted I returned them to my friend John. John then started to add the fittings and start building the superstructure. John cut holes, glued and installed the fittings in the freshly painted cabins. We researched the colors to use looking at the real boat and also the numerous versions of Imara that have been modeled.
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To create space so that the engines could be easily oiled and so that the complete steam plant could be removed from the boat, an opening that was wider than the superstructure was created in the deck. Unfortunately at first the opening was not large enough so I enlarged the opening further. I had returned the painted hull and superstructure to my friend John so that he could help with building the superstructure. John created two very clever and neat hinged covers in the deck for oiling the engines, the covers are also easily removed for when the steam plant is taken out of the boat. Once the model is completed it is hoped that the covers will be disguised well enough and not be to obvious.
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Bonjour David,
Great jib indeed and don't worry, we won't see anything when your boat navigates ok2
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To finish off the hull and to improve performance I invested in two larger dia propshop steam props to replace the props that came with the model. The 80mm props will help achieve the same speed with lower rpm and save steam, there by extending run times – at least thats the theory! If nothing else, they look fabulous.
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Those 80 mm diameter cast 'Propshop' propellers certainly do look magnificent Dave :-))
Without thinking or going down a Rabbit hole, I was surprised to see both as installed for inward-turning for Fwd?
Obviously ;) I had an outward-turning setup in my mind?
Derek
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Bonjour,
Derek, here is an endless topic, hundreds messages have been shared on lots of forums about it ! ok2
Based on my visits to shipyards and videos, I would have thought that David's setup is for fast boats like this example:
https://www.youtube.com/watch?v=elMnM2pTkh8 (https://www.youtube.com/watch?v=elMnM2pTkh8)
But I also have seen it on working vessels, so...
Never mind, Protean Design (ex Propshop) are the best in my opinion and Simon didn't pay me to say that :embarrassed:
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When I built the original Model Boats Magazine review kit of Imara in 1989, which was electrically powered, I fitted 45mm props. They were outward turning with plenty of thrust both forward and astern but the boat totally ignored the rudder (which is why a single screw version was subsequently brought out). Tank steering was the only way to control the boat.
In this case, inward turning screws which force the water against the rudder are likely to be more effective than outward turning ones. It's just the shape of the hull I guess.
Colin
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When I built the original Model Boats Magazine review kit of Imara in 1989, which was electrically powered, I fitted 45mm props. They were outward turning with plenty of thrust both forward and astern but the boat totally ignored the rudder (which is why a single screw version was subsequently brought out). Tank steering was the only way to control the boat.
In this case, inward turning screws which force the water against the rudder are likely to be more effective than outward turning ones. It's just the shape of the hull I guess.
Colin
Those things are pretty unpredictable anyway... We learned some about it in Nautical college, but even then the general consensus was that all rulles of thumb were fine and dandy but no guarantee at all...
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Thank you for the feedback, I had no idea that Imara had been available for so long, its a fantastic model. The direction of prop rotation is interesting, I did do some research before fitting the props, there were two schools of thought, so I went for the set up that rightly or wrongly seemed best suited for a Tug. I am happy to swap them over to see the difference. This is what I had read before I fitted the props - With twin props it depends on the rudder(s). If a single rudder inboard for manouverability, outboard for speed. Twin rudders it doesn't make much difference. (Perseverance has a single rudder).
On a tug viewed from astern there is debate as to which way for the props to turn is best. If they turn outwards, that is the port side turn anti-clockwise and starboard turn clockwise, the vortices or propwash lifts the stern upwards - it wants to ride on top of the propwash. If they turn inwards the stern wants to squat down - it is being sucked lower by the propwash.
The debate is which is best for towing, squatting down means it sets the props firmly in the water giving greater pulling power, but at the expense of possibly pulling the stern lower in the water. If it rides the propwash all of the horsepower available will not be given to pulling the towed item.
It will be interesting to see how the real world transfers into the model world so I will experiment and share the results.
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Anyone who has built an Imara/Perseverence will know that the funnel gets used as a handle for removing the main cabin structure, therefore, its very important that the funnel is very firmly secured to the cabin structure. This is the solution my friend John engineered to keep the funnel bolted firmly to the cabin structure.
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%) ...that soft solder between hex standoffs to the brass strip may get a little warm <*< atop of the top of the boiler shell Dave..........
Derek
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The new propellers look stunning!
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%) ...that soft solder between hex standoffs to the brass strip may get a little warm <*< atop of the top of the boiler shell Dave..........
Derek
It's not going to get at 100 deg C or more.
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It's not going to get at 100 deg C or more.
Soft solder can significantly lose mechanical strength at temperatures as low as 90 deg C, depending on the solder used.
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Thank you for the thoughts about the soft solder, will have to see if it works, but hope so having taken the time to insulate the boiler.
One of the differences between Imara and Perseverance is the addition of a cabin for the top wheel position, on Imara its an open wheel deck. John sketched out and made a cabin from scratch, there is not a drawing or parts for this in the kit. First photo shows the lower cabin (supplied with the kit) that John assembled, adding for fun extra items, a bottle of whiskey and some posters for the walls. Second photo shows both cabins. In this time wiring for LED lights was also added. The white metal poles for the railings were not used, instead brass poles and wire were used for all the railings. John did a good job of bending and soldering the them into position.
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adding for fun extra items, a bottle of whiskey and some posters for the walls.
I particularly like THAT style of detailing: Making it look like tiny old salts lived and worked there...
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Here is a photo of the inside of the newly constructed top wheel house complete posters and with LED light.
One of the big detailed features on the deck is the steam winch so some time was spent trying to make it look realistic, used. I have not painted or weathered models of=r fittings before so watched a few videos and had a go, here is the result. First the white metal fittings were filed to remove flashings from the castings, next they were de greased, then they were prepared with a thin coat of black primer. Once primed, the green, the matalic silver and the brass paints were applied. The finish was too bright and shiney, to new. A thinned wash of black was applied which when dried looks like oil residue and has dulled the finish to hopefully achieve a more life like representation of a steam winch.
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One of the things I have learned from this project is to treat every part, no matter how small, as an individual model in its own right. To clean it, to prepare it and paint it as if it is the finished model. Then when all the well constructed and finished individual parts are brought togeher, they really do stand out. Previously I would have assembeled the parts and then tried to paint the assembly, and then wondered why I was not happy with the finished item, not any more, treating each part on its on has been a valuable lesson for me.
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Blimey Dave that’s a lot of bits O0
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I didn't count all the bits but there is rumoured to be 1400 parts, if true thats a lot!
To bring life to Perseverence, crew figures were bought. The figures were cut out, the excess plastic from the moulding process removed so no visible lines could be seen on the parts. The surfaces to be joined were filed flat so that the joints when glued would be invisible. I have not painted figures before so experimented to try and achieve light and shade on the figures. First they were sprayed black, then to replicate the way the sun falls on an object and lights it, they were sprayed from a high angle downwards with a light dusting of white.
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Multiple thin coats of the final colours were then applied over the prepared crew figures, with the aim of creating shades of the colour rater than a solid uniform flat colour. The faces didnt go too well, I should have painted the eyes first, rather than last. Like the rest of the model, the aim was to have the crew looking like they were working, not factory fresh and clean. The crew were then positioned and fixed into place.
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The two lifeboats involved a a lot of work. They are vacuum formed plastic that needs to be cut out, then the top glued to the bottom part. The whiye metal fittings for the oars and rudder needed painting, then ageing so they didnt look brand new. The boats themselves were then painted, ropes with handles were added to the sides, then the boats were attached to the model. John had made a good job of assembling the deck and lowering gear for the life boats complete with the rigging. In fact John did such a nice job, the mechanism would actually work. As you can see from the last photo, the model is nearly complete.
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That looks amazing.
The only comment I can mak, is that the location of the oarlocks seems rather strange to me. They usually are placed on the coaming, as any place closer inboard sacrifices leverage for the oarsmen.
The davits/lowering tackle really looks the bizz...
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With the steam plant finished it was run on the bench a few times to bed the engines in, check that it all worked as it was intended to and make final adjustments. Here is a link to a video of one of the tests with the two PM Research No 8 Engines in steam and running on the bench and a photo of the completed steam plant.
https://youtu.be/-rXseq8Mt1A?si=5u-Bnh_bfPzXKLQB
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Nice one Dave, that is running soooo smooth and clean, and sound good too :-))
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Phil, thank you, the engines are quite mesmerising to watch, powerful as well. I was surprised how little noise the steam plant made, just the burner and a bit of hissing and the motion of the engines, plus of course the wonderful smell of steam oil. Anyway enough of that I promised to share with you the mistakes as well and when going through some photos, realise I hadn't told you about the decking.
When I purchased the hull a ply deck had already been installed. All John and myself had done was to cut some larger holes in the deck to access the rudder and new wider access created to allow the whole steam plant to be removed. To finish the deck and ensure it was water proof it was cleaned and coated with a very thin epoxy resin, this soaked into the wood, adding strength as well as waterproofing. The resin was rubbed down and airbrushed with a few very thin coats of water based grey primer, this took ages to dry and looked terrible. It was rubbed down and thin coats of the green paint was airbrushed over the top. The problem was probably me being impatient and not letting the paint dry enough between coats, but each coat seemed to reactivate the previous coat resulting in an uneven blotchy looking finish, that not only looked awful, but was not the right shade of green. It would have been better had I sprayed it over a black primer, but probably still too bright. Knowing a lot of the deck would be covered with planking I reluctantly left the awful looking paint to see how it looked after the planking had been applied, after all I wanted a worn working boat finish, maybe it would be ok? - I was kidding myself, in reality, I knew the colour needed to change to a darker shade of green.
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Clearly the green was too bright so a darker green was ordered. Here are some more mistakes with the painting. The water tanks, steering gear housing and deck hatch were all prepared, then primed with light grey primer, which was fine. The first green was then applied on the steering gear housing and deck hatch fitting, it looked ridiculous.
The steering gear housing was then primed using black, along with more parts. As an experiment, the new darker green was then applied over the black primed steering gear housing and over the original green of the deck housing. Wow what a difference the base colour makes to the final colour, lesson learned.
The darker green over black looked a lot more authentic so everything that had been light green was primed again with the black and then painted with the new darker green. To loose the factory fresh look and move towards a more weathered, worn dirty look, a thin wash of black was brushed over the deck hatch to generate more visual interest in the part. This was my first attempt at the washing technique, it taught me that it is better to apply several thinner washes than to try and achieve the look with one coat of thicker wash, its all trial and error, and top of that its very subjective, everyone seems to do it there way and have their own views about how far or not to go with it. The wash used on the deck hatch was too thick, for subsequent parts, several applications of a thinner wash were applied which seemed to be more controllable and achieve a more natural look.
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One thing John taught me was to make sure it was easy to access servos for future maintenance, he had learned the hard way after building Joffre. With this in mind the original servo and linkage for the rudder was repositioned so future access was easy.
With many of the major items painted they were installed in place on the decks, alongside with the repainted darker green decking, the model was now coming to life.
One of the most nerve wrecking jobs undertaken on the whole model was putting the name on the Hull. This took a long time, I have never held my breath for so long as each letter was positioned one at a time using tweezers. It's probably one of the first things people see, getting the size of the letters right tougher with the spacing was therefore important.
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Hi
I know that this is a bit late in the day, I think the colour you are after is called Brunswick Green
Fred
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Nearing the finish line it was time to finalise was the ballasting. First Perseverance went in the bath at home (yes of course I waited til my wife was out). Two kilograms of lead were added to the rear of the model and it looked ok. Next Perseverance went to the lake to float her there and make final adjustments to the positioning of the ballast. The two kilos of lead were placed as far away from the center line as possible to make sure any rolling was slow and lazy, I didnt want it bobbing about like a cork. The floatation test at the lake showed the lead weight needed to be moved further back, to lift the bow a bit, this was done and all looked fine.
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Fred, thank you for confirming the colour of Brunswick Green, it is appreciated. What surprised me was just how different these water based air brush paints can look, depending on the colour of the primer (white, grey or black) that you spray over, and then again, it also depended on how many light coats of paint are then applied over the primer, its been an interesting learning experience.
When building a house, traditionally to finish the house, the chimney pots are added in a topping out ceremony. So the last modelling job with Perseverance was to add the structure to the funnel for supporting the canvas that stops rain entering the boiler when the boat is not in service. This is a distinguishing feature of Perseverance and was not part of IMARA. The frame was constructed from copper wire that was bent to shape and soldered, then painted black.
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Having run the steam plant a number of times on the bench, it was time to install the steam plant in the hull and run it there as part of the final preparations for the maiden voyage. The steam plant fits on two locating pins. As the plant goes into the hull, the splines on the drive shafts from the engine are slid into the ends of the prop shaft. The only connection needed is for the rudder servo to the receiver. Everything else stays connected and is removable from the boat for servicing. The steam plant ran well in the hull with the superstructure on, here is a link to a video of it running without the superstructure. It's running here at 20psi but also runs very nicely at 40psi with the attenuator maintaining the pressure with the engines running.
https://youtu.be/4VnTjXnLfkE
The next step wass to confirm what is actually required by the Boiler Test Code for under 3 Bar Litres (Orange Book) for this boiler in terms of testing and recording, so that the model can be used on the different lakes that I visit.
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Re the message flags, they bring some added visual interest and John did a nice job of printing and installing them, and we have been ask if the flags mean anything? Well yes they do, its actually a personal message from us that says "Thank You NHS John Dave" its not just a COVID message, we both have a lot to be thank the NHS for, so it felt right.
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Re the message flags, they bring some added visual interest and John did a nice job of printing and installing them, and we have been ask if the flags mean anything? Well yes they do, its actually a personal message from us that says "Thank You NHS John Dave" its not just a COVID message, we both have a lot to be thank the NHS for, so it felt right.
Now THAT is what I call "on a personal note"...
Well done!
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Blimey Dave that’s a lot of bits O0
I did count them once on the 3rd one I built as I was sanding all the flashing and joint marks and got 1416 white metal and other fittings!.....boy were my fingers sore for days lol.
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Neil Building three is a big commitment and a great achievement well done, you are right about the fettling of the fittings, a necessary evil, but the end result is worth the sore fingers
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Building Perseverence has been a learning experience for which both John and I learned new skills, one such skill for John was learning about LED lighting. We discussed lighting and wanted the engine bay illuminated so it was easy to see to carry out oiling and checks. We needed navigation lights and also wanted some lights in the cabins. John cleverly hid the wires for the navigation and mast lights running the wires in grooves in the mast and installed the cabin lighting in ducting so it could be replaced easily in the event of a bulb failure, initially supplied with power from a stand alone four cell power pack, later an rc controlled switch will be added. The lighting works and is effective although it has been suggested it's too white and a softer yellow/white would be more realistic. Anyway the point was to learn and we have achieved working LED lights even if a few LED's were popped in the process!
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Bonjour David,
Great job indeed :-)) This boat deserves now a night navigation !
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Whilst not quite a night time navigation, here is Perseverance lit up, at the lake as dusk falls
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Very nice work, Dave. Congratulations!