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[DaveRuss]

Hi,
I am waiting for my delivery of the Riva Aquarama kit from Amati. I should have it by next Wednesday but I have a question. What glue would you recommend ? I already have some Aliphatic glue , would that be ok, or does it need to be waterproof ?
I will be varnishing the exterior only as I don't want to use fibreglass.
Also what sealing agents and varnishes are recommended.
Many Thanks
Dave

[david48]

You will be ok with the glue you have is it is waterproof Titebond 3 is the one I used and it is good .
The lads on the riva stand in Germany were using a 2pack system to get the glass type finish .
David

[pompebled]

I will be varnishing the exterior only as I don't want to use fibreglass.

Hi Dave,

If you plan on running the boat regulary, I'd strongly advice to cover the bare hull in a layer of fiberglass cloth and 24h epoxy resin.
Wood will always shrink and expand due to temperature and humidity and there will be cracks as a result.

A layer of glasscloth and epoxy will prevent your hull from developing cracks (and subsequent leaking and rotting.

The thin glasscloth will be completely invisible, once it has been applied, so your varnish will bring out the shine surface.
I used this on the outer surface of my M.A.S.":
https://hobbyking.com/en_us/glass-fiber-cloth-450x1000mm-48g-m2-ultra-thin.html
Pictures of the build (including glasscloth):
http://www.modelbouwforum.nl/threads/motoscafo-anti-sommergibile.152176/

Regards, Jan.

[DaveRuss]

Thanks David and Jan for your replies.
I won't be using it in the water very much as it is mainly going to be a shelf queen.But on a nice day I want to be able to take it to a lake or pond somewhere for a quick run out.
On that note, what brushless motors would be recommended for this boat and what shaft and props?


Also a very large and quite heavy box was delivered this morning and on getting home from work I opened it up.
I must say the box looks very nicely done with lots of details.On opening the box I was amazed at the quality of the items inside,looks superb.
I am very pleased about the seats etc as they are made from a spongy rubber and I think look quite realistic.I can't seem to see any flooring material but it could be in between the ply sheets but I will not be using that as I have decided to use mahogany sheeting for the flooring.
I have added a few pictures of my box opening and I hope it's not too boring for you all but I'm very excited about starting the build.
Thanks
Dave

[pompebled]

I won't be using it in the water very much as it is mainly going to be a shelf queen.But on a nice day I want to be able to take it to a lake or pond somewhere for a quick run out.

Hi Dave,

That's exactly the reason you should treat the hull with glasscloth and epoxy, or the tiny cracks, developed as a shelf queen, dried out in a well heated room, will most likely ruin your nice day at the pond...
Maybe not that same day, if you're lucky and the boat didn't sink, but the next, when the moisture soaked into the cracks, will start to make the wood buckle.

I'll come back with motor and hardware suggestions on another occasion, after I've studied this particular model.

Regards, Jan.

[DaveRuss]

Thanks Jan,I will bare that in mind.

[DaveRuss]

Hi,I've just ordered the Hobbyzone building slip from Hobbies Ltd, so that should be with me in a few days.
I'm just starting to number all the pieces from the beginning of the build before then starting the keel join and then onto adding the reinforcements on the ribs.
It's a bit messy epoxying the reinforcements to the keel but it will be well hidden.I will be doing the ribs etc with Aliphatic.
I won't be able to add the ribs onto the keel until my building slip arrives.
Thanks
Dave

[pompebled]

On that note, what brushless motors would be recommended for this boat and what shaft and props?

Hi Dave,

No doubt you are aware of the motorisation set by Krick (the European distributor for this kit, a.o.):
http://www.krickshop.de/Products/Accessories/Accessories-for-Ship-Models/Accessories-for-special-Shipmodels/Motorisierungssatz-ital-Sportboot-25035.htm?shop=krick_e&a=article&ProdNr=25036&p=197

This brushless set is a replacement for the 'old' set with brushed 600 type motors:
http://www.cornwallmodelboats.co.uk/acatalog/amati_motor_kits.html#aA1608_2f02

As you can see the price difference isn't that big, but as you specified brushless, I'll leave the brushed motors be.
On a side note; in general, the low end motor response of a brushed motor is better than that of a brushless motor, so if crawling along is going to be most part of your running the boat, reconsider a brushed motor set-up.

Brushless set-up:
The motors used in the link are sold by Krick for €34,90
http://www.krickshop.de/Produkte/Neuheiten-2017/MAX-Marine-P358-910-KV.htm?a=article&ProdNr=42434&p=21462
I have the same motor in my spare drawer with a Turnigy sticker on it:
https://hobbyking.com/nl_nl/turnigy-d3536-9-910kv-brushless-outrunner-motor.html
You can have two for less than one from Krick...

The Seaking 30A ESC (of which you'll need two, one for each motor) is this one:
http://www.dhgate.com/uk/hobbywing-seaking-30a-uk.html
Hobbyking sells the rebranded Flycolor ESC for 'slightly' less:
https://hobbyking.com/en_us/hobbyking-30a-boat-esc-3a-ubec.html
Again, you can get two for the price of one Seaking.

As all these items are manufactured in China, the chance of receiving a dud is equal for all brands.
I've tested the Flycolor ESC for the manufacturer and it worked fine.
Get a programming box with whatever ESC you decide on, it makes life so much easier (scroll down in the link for the HK one).

Propshafts:
If you built the boat, following the instructions, the propshaft angle will be on the steep side, as that is how the 1:1 propshafts are built in.
For the 1:1 boat, this isn't a problem, as these boats obviously run very well.

For a model 1:10, the water isn't scaled down and a too steep a propshaft angle will push the bow down when sufficient power is applied (= crappy running attitude).
For a model, the propshaft angle should not exceed 7°, preferably less (see the pictures in my build thread, link in earlier reply).

In case of the Riva, this means either long propshafts, the motors will (have to) go under the front deck, as the interior is in the way, or shorter propshafts, with the motor on top of the shaft, power transfer via toothed belt.
The latter also allows for a workable propshaft angle, but needs propshafts with a ballbearing inside the hull to cope with the unilateral load of the belt.
http://www.raboeschmodels.com/index.php/nl/component/virtuemart/marine-accessories/propeller-shafts/propeller-shaft-301-series-07-10-detail?Itemid=0

With the long propshafts, you can use a Compact shaft system where the motor is bolted directly onto the flange, using a solid coupler to acheive 100% allignment for a very quiet drive:
https://hydromarine.de/product_info.php?products_id=147
The link is just an example, these shafts can be custom made to fit your requirements.

Something else a (running) Riva model needs, is wider sprayrails than on the plan, to prevent the bow wave from crawling up (and onto) to the deck, as can be seen in the various video's of this type of boat.
In real life, such a horrible running attitude would upset the boat owner (and his passengers) to no end...

Regards, Jan.

[Mark T]

Hi Dave just a thought - when your using epoxy buy some IPA (Alchohol) it cleans epoxy up really well. It also cleans it off all of your tools and brushes when it gets on them too 

[DaveRuss]

Thanks for taking the time to find out all those details Jan. I will probably go the Hobbyking route as I've had plenty from them in the past.Regarding the prop shafts etc, bit over my head with those so I'll stick to what Amati recommend.
Thanks Mark, have just ordered some from Amazon.

[pompebled]

Regarding the prop shafts etc, bit over my head with those so I'll stick to what Amati recommend.

Hi Dave,

That's where the knowledge and expertise of this forum comes in handy, you don't have to know everything...

Regarding picture DSC00348.JPG
There's a plastic bag with two metal rods and two pieces of brass or copper piping.
Could you please measure the length of the rods and make a detailed picture of the ends?
If one end doesn't have M4 threading (assuming the rods are Ø4 mm) with the other end just smooth, you may have to cut thread on those rods, preferably left and right handed, in order to be able to fit some props.

If this is 'what Amati recommends', there should also be two 'A' frames and bushings in the hardware that came with the kit, some pictures of those parts would be nice to, so we can make an educated guess as to Amati provided these items to go with a static display model, of if it's actual running hardware.
If the rods are a snug fit inside the brass/copper tubes, I seriously doubt it'll work properly as running hardware, as there will be no bushings on either end of the tube.

The tubes will hugg the shafts over their entire length, with grease used to keep the water out, the drag inside those tubes will be huge, putting a lot of strain on both motor and ESC.

No worries, there's a way around it, but I'd like to know for sure what these items look like before I make suggestions how to go about ir.

Regards, Jan.
 

[martno1fan]

Ill second Jans recomendation for covering the boat with a thin layer of glass cloth and epoxy resin. At the very least coat the wood with 2-3 thin coats of slow setting epoxy resin,i use an old credit card sraping off as i go so its the thinnest coat ,repeat this 3 times and it will be fine.The epoxy with also bring out the natural look of the wood just as well as any varnish.If you do this you wont need the cloth ive done may wooden boats this way over the years .

[pompebled]

Hi Dave,

Here's a video that shows how well placed sprayrails keep the bow wave from crawling up to the deck:
https://youtu.be/14D5MC51WG0
This Riva has the same motors I linked to, but with a higher Kv

Here's the build thread:
https://www.rcgroups.com/forums/showthread.php?2441334-Another-Amati-Riva-Aquarama
Pay attention to his choice of propshafts (Raboesch) and post #68 regarding the use of glasscloth and epoxy...

On another note; all build logs I found mention that this kit is designed as a static model, it's too heavy for a running model (hence the use of the lighter brushless motors and Lipo batteries)
The builders that took notice of this fact built in 'lightness' by removing as much wood from the structure as possible and took out sections that didn't affect structural integrety after the hull was finished, but before the deck was installed.

I know this sounds daunting in a first build, but for a well running boat it is essential to scrub as much weight as possible.

Regards, Jan.

[DaveRuss]

Hi Dave,

That's where the knowledge and expertise of this forum comes in handy, you don't have to know everything...

Regarding picture DSC00348.JPG
There's a plastic bag with two metal rods and two pieces of brass or copper piping.
Could you please measure the length of the rods and make a detailed picture of the ends?
If one end doesn't have M4 threading (assuming the rods are Ø4 mm) with the other end just smooth, you may have to cut thread on those rods, preferably left and right handed, in order to be able to fit some props.

If this is 'what Amati recommends', there should also be two 'A' frames and bushings in the hardware that came with the kit, some pictures of those parts would be nice to, so we can make an educated guess as to Amati provided these items to go with a static display model, of if it's actual running hardware.
If the rods are a snug fit inside the brass/copper tubes, I seriously doubt it'll work properly as running hardware, as there will be no bushings on either end of the tube.

The tubes will hugg the shafts over their entire length, with grease used to keep the water out, the drag inside those tubes will be huge, putting a lot of strain on both motor and ESC.

No worries, there's a way around it, but I'd like to know for sure what these items look like before I make suggestions how to go about ir.

Regards, Jan.

Hi Jan,
Thanks again for your efforts.
I don't mean to use the shafts in the kit as they are for static display only.
If you still want the measurements I will get them for you though and they are threaded.
Regarding the motors, if I use the Turnigy outrunners  am I right in thinking I will not be able to use a water cooling jacket on them ?
Or do they not need cooling?
Sorry for all the questions.
Thanks
Dave

[DaveRuss]

Ill second Jans recomendation for covering the boat with a thin layer of glass cloth and epoxy resin. At the very least coat the wood with 2-3 thin coats of slow setting epoxy resin,i use an old credit card sraping off as i go so its the thinnest coat ,repeat this 3 times and it will be fine.The epoxy with also bring out the natural look of the wood just as well as any varnish.If you do this you wont need the cloth ive done may wooden boats this way over the years .

Hi Martin,thanks.
What resin would you recommend. Also when that is done I take it I still need to varnish. I think i prefer this method than to start with fibreglassing.
Thanks
Dave

[canabus]

Hi All
The different motors is range is:-
D3536/9-910 370watts
D3536/8-1000 430watts
D3536/6-1250 500watts
D3536/5-1450 655watts

The later require a 45Amp ESC, but, if you get these to start with you can upgrade to the more power motors later.
The power rating is on the higher battery voltage.

[Martin (Admin)]

Some great information coming out in this build blogg, thanks Jan, Dave, Martin!

I too will be following the resin / cloth / tissue covering processes with great interest..... I've never been brave enough to try it!   

[pompebled]

Regarding the motors, if I use the Turnigy outrunners  am I right in thinking I will not be able to use a water cooling jacket on them ?
Or do they not need cooling?

Hi Dave,

Don't hesitate to ask if anything is unclear, that's what a forum is for!

Depending on the propsize and pitch selected, these outrunners need no to very little cooling, If you've seen read my M.A.S. build, you'll know it took over an hour in the blazing sun for my (black) outrunner to get too hot.
The watercooled mount is something you can easily make yourself, or buy.

In the Riva thread I linked to, the builder uses the same motors, but in 'airplane' configuration, this allows him to use standard watercoolers (in red) to put between the mount and the motor.

Every electric motor produces some heat, outrunners are no exeption, so if you want to add a watercooled mount, just say so and I'll find you one.

Regards, Jan.

[canabus]

https://hobbyking.com/en_us/36-size-adjustable-motor-mount-with-water-cooling.html

Hobbyking water cooled motor mount kit.

Canabus

[pompebled]

I think i prefer this method than to start with fibreglassing.

Hi Dave,

Adding a layer of glasscloth and epoxy resin (the 24h kind!) to a wooden hull is a piece of cake.
That's easy for me to say as I've been working with the stuff for over twenty years, but it really is simple when you do it by the book (or my book...).

Realizing you cannot just throw a piece of glasscloth over the upside down hull and add epoxy resin, is the first step.
I added a few pictures of my M.A.S. hull, which is basically a box, as an example.

I added glasscloth pieces on every individual surface, using paper templates to get the size correct.
These were put in position and tapped onto the wood with a small brush and epoxy resin.
As you can see the sections were slightly oversized, once the epoxy has cured, I cut the overlap with a scalpel, or an industrial razor blade and sand the edge flush.
There is no overlap with the adjacent surface, it's just the thickness of the cloth and the resin that forms the edge.
Reason for this method, is the fact that all running surfaces of this stepped hull need to stay sharp, so the waterflow will break off the sharp edges instead of crawling up.
Another reason is that you can't fold glasscloth around edges that sharp, the tension in the glasscloth will make it work itself loose and round the edges with air trapped underneath the glasscloth.

After all surfaces have been treated, the hull is sanded (very) lightly, making sure not to break the glasscloth surface, and one or two extra layers of epoxy resin era brushed on, as thin as possible, to avoid runners.
Once that is done, the weave of the cloth is invisible, 'drowned' in the extra layers of epoxy resin.
Now you can add varnish and paint.

I added sprayrails after the hull had been covered in glasscloth and epoxy, as the edges needed to stay sharp for the sprayrails to work, the wood was brushed over with epoxy resin to make it waterproof.

Let me know if you have more questions.

Regards, Jan.

[pompebled]

If you still want the measurements, I will get them for you though and they are threaded.

Yes please, knowing the length helps source suitable running gear.

Regards, Jan.

[DaveRuss]

Hi Thanks to all the very very helpful responses.
My Hobbyzone Building Slip arrived today and it looks a really nice bit of kit, but quite complicated to put together with very basic instructions so it will take me an evening or two to assemble.
I also ordered the Mahogany for the flooring last night, also thinking of using it for the seat bases as well.
After a long day at work I'm too tired to build the slip tonight so I'll try tomorrow all being well.
I will try and get the measurements for you tomorrow Jan, just too tired tonight.
Thanks again
Dave


ps Still unsure of the glass cloth yet but I've plenty of time to think about it.

[Daleb]

Hi Dave,
I am currently building my first wooden (mahogany) boat, a kind of gentlemans 1930's racer (Aeronaut Jenny) and was very dubious about covering with fibreglass sheet as I had never done it before.
I eventually bit the bullet and went for it and to be honest it's not as difficult as it may seem. So pleased I did it now and would back up the guys on here who have recommended you glass the hull.....go for it 


Good luck with your build and hope you enjoy it as much as I am...


Dale.

[ukmike]

Hi David.
Scroll down the subjects in this section to my Aquarama build, it may be of some help.
My advice re glass cloth and epoxy, particularly on this model, is FORGET IT .
Works well on some models but definitely not this one.
Mike.

[pompebled]

Works well on some models but definitely not this one.

Hi Mike,

Could you elaborate on that?
I've glassed several hulls, including ones considered to be 'difficult to glass', never had any issues.

Regards, Jan.