composite keel

Found two interesting articles on the web about making composite keels. Really, a means for home builders to avoid castings and make up a keel from wood, epoxy and whatever lead they can find.

http://bateau2.com/content/view/63/28/

http://www.amateurboatbuilding.com/ProjectJustRight/chap08/Chap08.htm
(down towards the bottom on that second one)

Wondering a few things,
1) general impressions
2) could standard lead flashing that you might get at a home center be
used in combination with epoxy?
3) safety: is this keel going to break up and fall off at sea?
4) Is there a max size for this? If you want 1000lbs ballast for a 26 footer, is this method reasonable?

Sam

 

Since no scantlings are given, yes you can do it.

 

Here in Sweden the "Altiett 35" (http://www.maxknots.com/) uses a keel that is built with kevlar halves upon a steel framework. The bulb is bolted at the end of the blade in T-style. The keel blade is mounted in the keel case that rises from the bottom and up to the deck, in my opinion a very robust construction, and easy to build.

 

Complex but fine composite keels

Yes, the keel on the Altiett35 is a fine example. But it is also a complex keel to build. It is built around a steel framework with 2 steel tubes and a steel blade (rear) connected with steel plates welded together. Then you put this construction into a lead bulb form filling it with lead. Next you put the two kevlar/glass halves together, and finally you put a fine special mixture of quartz sand and polyester to fill out the distance between the steel framework and the kevlar halves.

The craftmanship shows when you need to build this to a max tolerance of 1 mm in thickness... But this is how it is done on the Alltiett 35.

A very robust construction. Visit the http://www.maxknots.com on the Norwegian pages, there you can find a picture series from the build process.