Keel Questions

[Mac Obsessed]

So say you were going to build a boat, and were going about it the old fashioned way- cutting keel and frames/ribs, gluing them up, planking, and attaching a chunk of lead to the keel. My question is, what kind of woods would be suitable for such situations? Would balsa work, or would basswood or something even stronger be necessary? I hope to build a boat similar to this one (http://www.vmyg.org.uk/pages/resources/plans/xmuna.htm) .
-Mac

[Earl Boebert]

A lot of information on traditional wooden model boat building can be found at:

http://www.usvmyg.org/construction.html

Cheers,

Earl

[Vince Hoffmann]

Mac

1/8" birch plywood is typically used for frames, sheer and keel, with reinforcement around the keel box. Balsa is typically used for planking because it bends easily to conform to the shape dictated by the frames.

[amdaylight]

I would use 3/16" birch aircraft ply with a laminated bass wood keel and balsa planking. Once the hull was done I would then cover the hull in light weight glass cloth and resin. You could either build a separate lead casting or build a full hull and use lead or steel shot inside of the hull held in place with resin.

Andre

[fats_nz]

Thats a nice looking hull. Either is, or similar to a J class. I have used Cedar on my hull because it forms around frames nicely. I have used walnut sparingly as a contrast and for strength. Balsa is good but very soft so appeals if you are going to glass over it. I purchased a plank or red cedar from a wholesaler down the road and then asked a kitchen joiner to strip it into planks 3mmx15mm I also did the same with the walnut. It worked out to be very cost effective. Hope this will help

[Mac Obsessed]

I'm going to try scrounging around work for a piece of oak for the keel... I figure that If i want to build right I may as well go all the way and use the same thing as the big guys use. (One of the benefits of working with old wooden boats is that there's usually some leftover bits that didn't quite make it into a big boat.) Depending on how much I have left over, I might use some of it for frames/formers as well, and then plank with whatever wood I can find- likely balsa, but I might be able to find some more suitable wood.

[MILLERTIME]

I'm watching this build.

[slotracer577]

I would use cedar for the planking and 1/8 ply for the frames. Cedar is much stronger than balsa, but still easy to work with. It also has a nice dark red color when finished in clear.

John

[tigerbay]

You could use almost any softwood for the keel. As long as it is primed and painted to keep the water out.
Some 'farmed' hardwoods are soft enough to use.
Avoid tropical hardwoods as many are too brittle and can crack with age.

If you are going for a natural wood finish then you need to find timber that is very fine grained, as if it is very grainy it will not look scale.
Box wood (aka limewood), or some of the fruit tree woods perhaps.

[lamafever]

I wonder how can i make my own carbon fiber keel ? and rudder ?

[tigerbay]

I wonder how can i make my own carbon fiber keel ? and rudder ?

I don't know what I am talking about, I am just thinking out loud.
I wonder, is it worth it?

The main advantages of weight reduction are those above the waterline as they contribute to heeling.
Below the water they counter healing.

If the fins are the same size there is no reduced drag, and if you need the balast, then you will have to add it. Perhaps entailing a bigger keel bulb and more drag.

[mfr02]

The progressive lobby in IOM wanted, and eventually got, the inclusion of carbon for fins and rudders. You get the chance to keep the same rigidity for a smaller frontal area, thus less drag, and the saved weight can go into the bulb, lowering the centre of gravity and increasing the righting moment just that little bit that gives you the edge over the guy who couldn't afford it. The increased drag brought about by the larger bulb is tiny against the drag reduction of the thinner section fin.

[tigerbay]

:) Thanks for that MFR, informative as ever.

I have learned something useful today. :cool:

[Mac Obsessed]

I asked Captmsr a similar question, and his answer was largely the same- Stick with some soft wood (Pine or Cedar) for the keel/deadwood, plank with whatever wood is soft enough to bend easily. Thanks for all the help, and I'll start a new build post as soon as construction begins.
-Mac