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[ADHamburg]

Good Day to you all,


my name is Andreas and I am from Northern Germany.


After some time with RC-planes (not soo successful, I "sank" them all...) I fell a few years ago in love with a motor yacht built by Messrs. Hinckley from Maine in the US.


It is a Hinckley T 38 R (Talaria 38 Runabout), which is having, for my taste at least, very beautiful lines and is a bit different in the way, that it has quite a lot of power (2 x Volvo Penta with each 435 hp), that is driving two Hamilton water jets, which give the vessel a top-speed of 37 knots and a cruising-speed of 32 knots (at a total displacement af approx. 11 tons).


The way these jets are controlled is quite unique and allows a "captain", even if not an old hand, to execute almost any maneuver in restricted waters in small ports. The magic word here is "Jetstick", a Hinckley-patented gadget with clever ideas incorporated.


The real-world price for such a yacht, new, ex works, is about 1 million US$, somewhat too much for me...


For that reason I have decided, that I want to build a model of the Hinckley T 38 R, that looks like it and can do the same wonderful maneuvers as the real one.


So, where do I stand in the model-builders world right now?


I would say, I am a rookie with very ambitious plans and some of you may smile about my ideas, but I don´t care.
I have not set any time-plan, as long as the model swims before I die (which, hopefully still is some decades to go...)


My idea about the model is, to build it in a scale of 6,28:1. This was dictated to me by the available model water jets, as far, as I could research. This would bring it to a total length of about 180 cm and a width of approx. 53 cm. The draft should not be more than 11 cm.


In this moment I have no plans as per which I could build the hull, I have to do it all on basis of pictures collected from the internet.
I wrote to Hinkcley to ask, if they had some plan, that I could use to build the hull in precise scale, but even after another friendly prompt for an answer, I had not received any reply from them whatsoever.


So much about my plans as a model-builder.


About myself:
I am married since more than 23 years and have one daughter, 21 years old. The life of one man against two women sometimes is hard, but all over I am quite content.


Business-like I am connected to the shipping-industry, where I deal with spareparts for marine diesel engines.
I hope to meet a lot of nice folks around here.


Greetings,


ADHamburg (aka Andreas)

[pompebled]

Hi Andreas,

Welcome to the madhouse!

That's quite a plan you have there...
At 180 cm you'll have plenty of room to make the convertable top working, if you're willing to go that far.

Which jets are you going to use and which motors, if I may ask?

Schöne Grüsse, Jan.

[Neil]

The life of one man against two women sometimes is hard, but all over I am quite content.

you want to try living with3 women Andreas............
as to your project, do you have photographs of what you want to achieve......I'm sure we would all like to see them.
 
neil.

[pompebled]

http://www.hinckleyyachts.com/Jetboats/t38r/t38r.php#

Jan.

[ADHamburg]

Hallo Jan,

regarding the jets, I'm looking at the HobbyKing model as well as at the Kehrer-machines.
However, almost all models of that size have the problem, that they don't feature the typical Hamilton reverser buckets.

Regarding the motors I haven't decided or chosen yet, the only thing I know for sure, is, that it shall be electric.

Regarding pictures, thanks for posting the Hinckleys-link.
I'm writing now from my phone.
Tomorrow I'll post a few other pictures, that I was able to capture from the net, from my desktop in the office.

Greetings,

Andreas

[Tug-Kenny RIP]

Hi Andreas,

Welcome to Mayhem where we never close.   

How are you on scratch building?  I have seen the pictures and it doesn't look too bad to be able to form the shapes of the hull.  Will you be making it all or are you looking for a hull or kit, etc.

Cheers

Ken

[ADHamburg]

Hallo Ken,

at the moment my plan is to cut a positive form from styrofoam, then build on that a glasfiber-reinforced resin negative form and then use that to build my beloved model hull.

I hope that is not the wrong strategy...

I am sure, there will still be lots of opportunities for mistakes.

Greetings,

Andreas

[Tug-Kenny RIP]

Oh goody. Please keep us informed and up to date with some pictures.

It looks a classy craft.   

Cheers

Ken

[pompebled]

Hi Andreas,

Making a positive out of foam is a relative cheap way to make a hull.
If you don't want to go through the mould making process, it's also possible to just cover the foam hull with glasscloth and epoxy and use that as a hull.
Works like a charm and you'll still have a lot(!) of sanding to do...

Before deciding on the size, I would make up my mind which jets to use and find a motor that will be able to drive it.
For an electric motor, driving a jet is considered 'hard labour' (Schwerarbeit) and the HK jet is usually powered with a 25cc (or bigger) petrol engine.
That kind of electric power is expensive, not only the motors and ESC's, but also the batteries and charging devices required will set you back considerably...

Regards, Jan.

[ADHamburg]

I have had a chance to look once more at my collected data, especially once more at the original data of the real HamiltonJet HJ274.


The water-jet I had chosen so far, was the Graupner Jet-Drive 5. It is similar to the HobbyKing jet, but slightly smaller.
Based on this, I came to my scale of 1:6.28


Regarding the size of the motor, it certainly is a consideration, but I would prefer the electric option because of noise, smell and easier installation. Also, vibrations will be less, I hope.


OK, I must go now. Wife is waiting.


Greetings,


Andreas

[pompebled]

Hi Andreas,

I have no idea when, or if the Graupner Jet-Drive 5 will be available again, but this jet needs 3-4Kw, preferably more, to be able to use the capacity of these jets.

On a minimum of 6S that would mean at least a watercooled Leopard like this:
http://www.rc-raceboats.de/shop/lbp5692/3y-730upm/v-847.htmlWith 730Kv on 6S the jet will have just under 15000 rpm under load, just as the doctor (Graupner) ordered.

If money is no issue, there are always the more powerful Lehner, Plettenberg and Neu equivalents.
As an example the LMT 3080/13 (404Kv) on 10S Lipo: 14544 rpm under load.
Price without watercooling jacket (required!) €608,00
http://www.lehner-motoren.de/3080/

I don't want to look up what the ESC for these motors would cost...

Regards, Jan.

[Circlip]

Another method to think about for hull construction.
 
   If it's a hard chine design and you've made a foam "Plug", skin the outside with "Depron" panels and then skin this with epoxy and glasscloth. This should give a smoother surface. Pull the plug out, add a few bulkheads and stringers and you've got the hull.
 
  Regards  Ian.

[pompebled]

 If it's a hard chine design 

Hi Ian,

No it's not: http://www.hinckleyyachts.com/Jetboats/t38r/t38r.php

But strips of Depron instead of panels would also be an option.

Regards, Jan.

[ADHamburg]

Oh, boys, you make me feel


- at home in this forum
- afraid of my own project


Thanks a lot for your interesting input, This is very, very helpful!!!


Once I have sorted all this out a bit, I will revert back to you with my (new?) views and what and if I have done something at all already...


Thanks once more,


Best greetings,


Andreas

[Circlip]

No it's not:

   ??
 
   Looks to have hard lines to me Jan?  It's not round bilge. Same sort of lines to the Riva Aquarama.
 
  Regards  Ian.

[pompebled]

Hi Ian,

I agree with you that the bottom section would be suitable for Depron panels, but the sides (Riva like, as you describe it) would be hard to build with panels, I've seen 1:1 hulls build from foam strips, covered with glass and resin, so a similar approach would work for the Hinckley model.

Let's wait and see what Andreas comes up with.

Regards, Jan.

[ADHamburg]

Hallo All,


for forming the hull I had stated, that I wanted to use styrofoam. But chewing that I dea over, I have asked myself, if it may not be better to use PU-foam instead.


My reasoning is, that if I make a wrong cut, then it is no problem to apply new PU-foam at that spot and just do it again.


Does anybody have experience with PU-foam? Ist it a bad idea or can I follow it up?


Greetings,


Andreas

[pompebled]

Hi Andreas,

If you're thinking about the stuff that comes out of a spray can, forget it, this is horrible stuff to work with.

I recently had a plug (Urform) made of a boat, I didn't have the time myself, so someone else offered to do it for me.

The room between the formers should have been filled with 50 mm thick foam, made from insulation foam, the yellow, blue or red(ish) stuff, the drawing had been adapted so the 50 mm would fit exactly between the formers.

The idiot thought that using PU foam from a spray can would work faster, so he went along without consulting me.
It took him the better part of a day to cut the expanded foam down to the formers, only to discover the foam in the core hadn't cured...
When asked if he had read the instructions, which warned about applying too a thick layer, you can guess the answer.
It took more than a week for the foam to cure sufficiently and the sanding and filling could begin.
PU foam out of a can doesn't expand uniformly; there are huge bubbles in the mass and when you start sanding, they become huge holes, so the filling and sanding took ages.

As the project had a time limit, I took over and applied three layers of glasscloth and epoxy resin to finally have a surface that could be filled and smoothened without having holes appearing in the surface every time a bubble was sanded open...

Only if you use the two part PU foam, that has to be poured into a form (the frames of a boat, inside a fitting cardboard box for example) PU foam is an option.

If you make a wrong cut when using Styrofoam plates, it's easier to cut out a rectangular piece and glue in a new, larger piece with POR and sand it into shape.

Regards, Jan.

[ADHamburg]

Jan, thanks a lot. The bubbles occurred to me, but i ewasn´t aware of the uneven curing within the foam.


OK, so styrofoam it will be...


Greetings,


Andreas


P.S.: Are you professionally involved with model-building? You seem to know quite a lot!

[pompebled]

P.S.: Are you professionally involved with model-building? You seem to know quite a lot!

Hi Andreas,

Knowing a lot comes from making a lot of mistakes!
These forums make it possible to share information, so others won't have to make the same mistakes (and can make their own, entirely different ones...)

I have worked with polyester professionally for a couple of years, that's why I know a bit about making hulls.

The project I mentioned above was making 14 RC skûtsjes for an open air play last spring;







Regards, Jan.