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[Sandy]

Hi,

I am going to build a modl lof the steam launch Choupette which was featured in the recent plans issue of Marine Modeller International magazine. It looks like quite a jolly boat.

I have received the kit and plans from Traplet.

As this is the first model I will be making for many (approx 30) years I was going to use an electric motor. Could anyone who has seen the boat in the magazine or know of it (length about 1 metre, chine hul) recommend a suitable size electric motor please?

Thanks in advance.

Sandy

[50mm]

Standard 540 or 555 size should do the job for a steam launch keep the speed 'reasonably' scale like 15A esc will be needed.
  Run it off a 6v 4ha battery should give you around 3-4 hours of run time, if you add extra features like a smoke machine for the smoke effect that will draw some power, decreasing the run time (but if you have room for it, get a 12v 7ah battery in there for an all day runner) depends what you want to add as extras to the model depends on the power pack you will need.

just note if you run extras like a smoke machine and lights you will need some type of power distribution board as lights tend to be 3v smoke machines 6v or 12v and your esc+ motor can run on 6 or 12v. im sure someone here will be able to link you suitable parts to make a decent model  

[Aeronut4]

I've just started building a Choupette for steam power - I'd be interested if you care to post any comments on your build.  As for power, as has been said, almost any 540/550 type of motor on 6 Volts ought to give bags of power - it's no speedboat!

[Sandy]

It's nice to know someone else is doing it.

I will post a few photos. On holiday this week and hamstrung by not ordering or obtaining a prop shaft early enough. Local shop (Paisley Modle Centre) did not have a ten inch shaft and were awaiting a stock order. So ordered from cornwall last Tuesday. No sign of shaft, so phoned and found it was only sent on Saturday. Not in post today (eagerly awaiting postman tramping through the 6 inches of snow it dumped here from 1000 to 1300).

I am annoyed that I was tardy in obtaning the shaft, and miffed that Cornwall took four days from my phone call before actually sending it.

Lesson learned. I think I will give PMC my business as best I can for bits and pieces and order online for other stuff (radio, etc).

[Sandy]

Here goes.

Please bear in mind that (a) it is more than 30 years since I did a model boat and (b) I am making it up as I go along:-

Glued all the bits together using Titebond II..

[Sandy]

Found that, despite best efforts, the keel was 'bent'over its length. Left it a couple of nights 'reverse bent' using bits and trusty bricks. This worked out quite well but not completely.

Added stringers around outside of deck. two strips to get width, then added some 5x5 Obechi around inner deck hole (see last photo in previous post).

Added little 1 inch strips at curved front end and used dremel to turn it back so it fitted and was curved. I did this to supoort the vertical splash deck better.

Dummied it all up on the B&D workmate, simulating the propshaft with a pencil of approx 8mm diameter and found that the deck needs a fair bit of sheer. So ... bent deck.

[Sandy]

Titebonded front and rear formers to keel and modigied them so atht the Obechi inner stringers would fit. Carefull marked fromers as to what side was front then promptly glued rear one in backwards.

I also found I had to be a bit 'creative' with the positioning of the formers viz a viz the plan. Mostly it was done by eye.

 I also glued the eight bits together to form the four hull pieces and found that, on mine, the side pieces are wrongly marked. Wahte says rear is actually front, but, you can tell that the abgled end is obviously the front bit to conform with the stem piece.

Mounted again on the workmate I epoxied (Z-Poxy, 30 minute) the deck to the formers.

Note radiator to get some warmth in kitchen.

[Sandy]

Ah-hah, but beforehand (apologies for being out of sequenece) I realised that I may need a hatch to access radio gear under rear deck so I cut a hole for a hatch. Drilled holes in corners by spinning drill bit between fingers (memo, must get pin vice, or better still, cirrect drill bit chuck for Dremel) then used 80 year old fret saw (and blade by the looks of the first edge) to cut deck hatch.

Braced underside of hatch and built little lips in the corners to support hatch, but the plan is to plank deck and make a 2 or 3 mm walnut lip around the hatch to cover saw marks.

[Sandy]

In the meantime I had glued the transom to the smaller piece of keel and fitted Obechi supports along the rear edge of the deck so that the transom would but up against it (visible in top photo in above post).

Using pencil and clamps I 'attached' the transom and keel and I now had a reasonably workable hull form to trial fit the sides and bottoms. Bear in mind that, as the prop shaft isn't fitted and the transon attached I could not fit stringers yet.

The side seem to line up quite nicely and fit quite well, as long as the deck is sheered.

The lower hull parts were a totally different matter. The bending of them at the front is very difficult and lots of naughty words (forgotten since the last time I 'fiddled' with an old classic car) filled the house.

I found that the lower side pieces are way too wide.

So, the plan is to fit them first, and sand them back.

[Sandy]

Once the lower sides were dummied up, I then constructed stringers.

I have several bits of long ply (make sure you buy 1 metre lengths, not 36 inches).

I used the 3x7mm bit as closest to the formers and another 3x5mm bit alongside it but which will be closest to the upper hull sides. Using both seems to 'fill' the notches in the formers and line it up nicely. It also means on my trial rig that with the lower sides clamped in place I can slide each in from the rear al the way forward and work out how much chamfering each front end needs. You can slide them out, cut or sand and slide them back in.

I also used 3x2mm ply for the keel stringer. Again, two are required, one on top of the other to fill the 'stringer gap' in the formers.

[Sandy]

And here is where I am at until the propshaft arrives.

Here's a photo of the stern showing the excess of the stringers hanging out. Nothing is glued yet but I have left it dummied up so the ply at least takes a bit of a twist for the bows.

My plan was ... is ? .... to work backwards and leave it all dummied and then apply Epoxy of both 5 min and 30 min variety and glue the lower hull side to the formers and bow and while that is drying apply it all around the stringers as well. In other words, instead of builidng the frame with the stringers and glueing the sheets over the top, I actually use the hull sizes to put the stringers in the correct place. To me it semed difficult to get enough 'bulge' outwards of the stringers between the front former and the stem piece to correctly meet the upper edge of the lower hull sides .... if you see what I mean.

From the photo in this post, you will also see that, amybe about a third of the way from the rear former to the transom, I will need to cut of the outer stringer piece as the transom cut is only big enough to take the inner piece.

[Sandy]

If the propshaft arrives tomorrow I intend to plough on and hopefully have a fillable and, maybe, paintable hull by the weekend.

No idea if what I have done is correct, or what I intend to do is correct either, but so far it seems to be working.

How have you got on with yours?

All the best
Sandy

P.S. Eek, just re-read my posts, apologies for spelling and poor keyboard/finger interface. The fingers are way ahead of the brain.

[Aeronut4]

Hi Sandy - many thanks for the photos and description - very helpful!  I'll try and take some photos of how far I've got so far, but it isn't very far!  I didn't buy the cut parts from Traplet (cheapskate!) and spent a fair bit of time cutting out the keel and formers/bulkheads.  I did order a propshaft in time and now have that installed in the keel.  I'm just fitting the keel to the building board/jig and will then start attaching formers and stringers.  I've noted the problem with the deck - it appears to have a curve on the plan, which I think may be difficult to reproduce with so few formers supporting the stringers.  I may have to add some temporary formers to get the shape until I have the stringers and deck fitted.  I'm hoping to be able to avoid cutting any hole in the rear deck - I think it should be possible to get the servo in and out by mounting it to a removeable bracket which is secured with horizontal screws - we'll see!  If I may, I think I should point out that you may be better off using a good wood glue, rather than epoxy, for the build.  I'm not a huge fan of epoxy for wood, as the wood contains oils and resins which seem to compromise joint strength in my experience.  Wood glue soaks into the grain and also swells it, making for a stronger and firmer joint.

[Sandy]

Thanks for the glue advice. I will use the Titebond for the rest.

The hatch was a great will-I, won't-I thing. The plans show a small hatch off set for the servo. I wasn't too keen on using the servo link set up proposed on the plans. having a slot in the transom semed a bit suspect from the point of view of water-tightness. I did think of using the tiller arm to steer her, using a servo on its side with a long arm and a Y-piece at the end which would move the tiller arm left and right.

Eventually I decided on the hatch for easy access for components.

Can I ask how you will be sealing inside the hull at the side joints/bow/stern ? The magazine mentions epoxy resin but I am a bit unsure as to what this is and how you get it to the critical areas at the bow and stern once the hull is all completed.

All the best

[Aeronut4]

Titebond is a good choice, I prefer Titebond III, as it's supposed to be 'waterproof'. I did consider other ways of operating the rudder, but am sticking with what's shown on the plan.  You have seen the piece of foam fitted inside, through which the rod moves?  As for sealing the inside, I'll cross that bridge when I come to it, if necessary.  I was hoping not to have to do that, as I was planning to give the outside of the hull a coat of thin glass cloth. Sorry, forgot to take the camera to the workshop today, will have to take pics on Friday now - work intervenes!  It's coming along though, got the bulkheads glued to the keel and the rudder is now ready to be silver-soldered.

[Aeronut4]

Finally took some pics today, when I returned to the workshop.  Managed to get the rudder silver-soldered to its shaft, now I need to make some more brass bits for it.  Made a start on the condensor/oil trap for the steam plant, will post a pic when it's done.  Next step is to add the deck and chine stringers - I'm laminating those from lime - it seems to bend easily enough!

[Sandy]

Very nice.

My prop shaft eventually arrived so all bonded in, and stringers glued in place.

Just mocked up the first lower hull piece. A little sanding of the stringers required then I will break out more glue and hopefully have at least one hull 'plate' attached some time tomorrow.

What size of propeller are you using ?

All the best

[gingyer]

Its looking good there sandy

[Aeronut4]

Sandy - using a 50mm propeller - about the largest I can fit without major modification - I hope it's large enough!

[Sandy]

Its looking good there sandy

Thanks, Colin.

I missed you a couple of Sundays ago. Decided to start with the Choupette to get my hand in. Plus, join the club, of course.

All the best

[Sandy]

Finally have all the pieces on the hull now. Been a bit slower than expected, but getting there.

Now need to fill and undercoat and do some shaping.

Ignore the 'side-rear' writing. The kit is wrong (I hope)  

[Sandy]

Finally have all the pieces on the hull now. Been a bit slower than expected, but getting there.

Now need to fill and undercoat and do some shaping.

Ignore the 'side-rea' writing. The kit is wrong (I hope) 

[gwa84]

looking good nice lines on this one 

[Aeronut4]

It's looking good Sandy!  I'm just about to start fitting the bottom skins to mine.  Can I ask how you clamped the skins to the keel stringers while the glue dried?  Having trouble trying to think of a way to do this that doesn't involve holes!

[gwa84]

could you tell me where you got the clamps with the soft rubber orange ends from seriously need some of them and cant seem to fined them