Cradle for a dinghy.

[Wild Wassa]

Good morning Skippers. I would like to build a solid (no supporting straps) wooden cradle for my dinghy. I do not know the technique for tracing around the hull, to the exact hull shape. The boat is hard chined and the cradle will be on wheels. Towards the stern, where the dead angle is slight is no problemo, but the compound curves towards the bow are too tricky for me.

Thankyou in advance for your advice.

Warren.

[ 08-17-2003, 08:48 PM: Message edited by: Wild Wassa ]

[daddles]

Simple. Mark a line on your boat where you want the cradle to sit. Cut the boat in two along that line. Take one part of the boat, sit it on your board and trace around it. Then glue your boat back together. The boat will no longer be any good of course so you sell it on Ebay for an extortionate price, thereby earning enough money to build another one, avoiding all the errors you made while building the first one.

There's probably a non-destructive method but it certainly won't be as counterproductive or time consuming as the one described above.

Richard
haven't had my morning coffee - can you tell?

[Wild Wassa]

Daddles, I'm a masochist I restore boats I don't build them.

I find your advice helpfull for other projects, but I might put your idea on the backburner for a while, with this one, :D .

Warren.

[daddles]

Darn, I wanted to come and watch.

I hope someone comes up with a sensible suggestion for this one because it's something I have to do to.

Cheers
Richard

[On Vacation]

Great advice, Daddles. You hit the nail on the head, with your advice. Thats how I do it. Gosh this site is great.

[Donn]

This will probably be taken as a neocon fascist approach, but I'd use the age-old approach. Tape carbon paper on the hull at the approximate support locations.

Estimate the rough shape of the support wood for the cradle, set the carbon papered hull into it.

Remove hull and remove blackened support wood.

Continue until perfect.

[Wild Wassa]

Donn and Oyster, don't take things personally lads, I know Fascists, ... because I am one.

Donn, your advice is where I'm up to so far. I'm not adverse to making a mould out of wood, glass and epoxy, to duplicate the correct shape, but a chap told me a technique for tracing that was so simple, that I've forgotten it.

My cradle will not be as lofty as this pair (taken from a Lightning site, photographer unknown), my boat wouldn't pass class measurements any way or weigh, and I'm not this tall.

http://www.imagestation.com/picture/sraid75/p12d0f33f058af96011bde0d4bffb8cf0/fb5c477a.jpg

I will also make the cradle to the width of the chines, wider than this Lightning's cradle. My boat and the Lightning are very similar.

Warren.

[ 08-17-2003, 09:33 PM: Message edited by: Wild Wassa ]

[On Vacation]

Will you listen to this neocon, if I take the time to show and tell you?? Easy as 1,2,3.

[Wild Wassa]

Oyster of course I will. One is only a Neo-con if one is a 'new conservative', after having been something else previously, like a Democrat, ... a bit like Wolfowitz.

Warren.

ps, One war changes nothing, although it has certainly changed a few good friendships on this site, ... would you agree Oyster?

[ 08-17-2003, 09:47 PM: Message edited by: Wild Wassa ]

[NormMessinger]

Donn's approach is great if you are a dentist fitting crowns.

Cut the rough shape by eye. Prop the piece firmly over the boat where you want it to be. Take a compass (no not that one, the one with a pencil on one leg and a sharp point on another.) open it some amount, lay the point flat on the boat, the pencil on the board, point pencil plane perpendicular to the tangent of the hull, trace line.

Lay the pencil on a block of wood, move wood over hull, pencil along form.

Lay bunk cloth on hull, cover with plastic sheet. Lay up four plies of glass in epoxy over cloth, lay plastic hose over Glass and then a couple four more plies. cure, remove, use for perfectly fitted padded support.

[On Vacation]

On a hull as you posted, its pretty straight foward. Rip a bunch of strips or just use a bunch of cutoffs and lay them across the hull, screwing the pieces together at points of interest. IN a round bottom hull, it will require multiple pieces screwed at hard points, and then scribe them to fit the conture or the hull with a compass and a pencil, or a piece of 3/4" board, turned edge ways, with the pencil taped to the top of it. In many cases only a piece 3/4"x 1 1/2" will give you a better scribe then a long piece. Transfer this a piece of 1/4 luan type, and cut out. Refine this templete before you cut the good wood. Make sure you put at least two screws at each point to insure it doesn't shift on you.

Make sure you do both sides all the way across the boat at the same point from the stern or a know point on each side.

http://www.imagestation.com/picture/sraid75/p7276eab5a50cdb8809136027863452cf/fb5c2f8b.jpg

http://www.imagestation.com/picture/sraid75/pd512a7b9824101b583c8a9737c823dd3/fb5c2f3b.jpg

[ 08-17-2003, 10:15 PM: Message edited by: Oyster ]

[Wild Wassa]

Norm, you make it sound so simple. It certainly sounds like fun, ... model making.

I'll drill a hole in the wooden block for the pencil. I'll construct the wooden curve out of small and larger wooden blocks, cutting along the pencil line will remove the steps, I'll then lay and glue the moulded strip to the wood, and backfill with a runny compression strenghth filler if needed, and then cover with the felt.

Thankyou Gentlemen.

[Wild Wassa]

Oyster, Excellent. The curve is not an even curve. For or aft or athwart.

The pencil tracing will need to be done on both sides of the forward support. For the forward support I'll need to make two templates, spaced at the width of my new support, for the hull's curves, she curves athwart and aft. As I said, making the rear support is not an issue, this one is child's play.

Cheers and thanks Mate.

[ 08-17-2003, 10:24 PM: Message edited by: Wild Wassa ]

[On Vacation]

In addition to this piece, you can add little pieces to the bulk pieces at the skeg, shaped to fit any fillet type curves, and then screwed in place. Any angle in the foward section should be scribed from the front side, or long point. Make sure your roughin piece is right angle or plumb while you are fitting the pieces. Waste 1/4" luan before you waste the good wood. If you really wish to get fancy, the rounds on the edges can be done with another rough in piece, cut with an edge of a grinder, or a jigsaw and screwed to the existing boards. This same technigue can be used to fit the inside bulkheads and seat thwarts going across the hulls in smaller boats. No angles to measure, and lengths to worry about.

[skuthorp]

Hi Warren. I have one to carry the Mack on top of the car right way up. Deep and snug so the boat can't move either way and with a roller at the back for easy loading. I made card templates and allowed for padding. It carries perfectly at 110K.

[ 08-17-2003, 10:33 PM: Message edited by: skuthorp ]

[Wild Wassa]

Thankyou for the extra information Gentlemen.

While I plan the cradle, and after working backwards, from what I imagine the finished cradle will look like, to the start of construction, it appears as though different aspects from everyone's advice will be very helpfull. Cheers and thanks again.

Skuthorpe, My boat is only 15Kg heavier than your McG, :eek: The boat is too hard to work on when she sits on the trailor. The cradle is only for when I turn the boat over during her restoration. I will not be transporting my dinghy on the cradle.

Warren.

[ 08-18-2003, 09:15 PM: Message edited by: Wild Wassa ]