Making a Rudder

[Guest]

I'm looking to make a new rudder in Oak. Anyone out there had experience of this, for example it will require a 3" X 3" post for the main section but what joints to build up the remaining pieces and what gaps should be allowed for expansion. Is wood the material to use?

 

[Mirelle]

There's a good description in Verney's Complete Amateur Boatbuilding, and a rather high powered description (bronze rudder stock!) in Watts and Jurd. Lloyds yacht Rules covers cross section of stock etc.

Yes, wood is fine, oak is fine, either strap it together or bore for long bolts - amateurs of my modest competence feel happier with straps! If the oak is seasoned, don't worrk about expansion, but expect it to contract when left ashore for a long time.

 

[Sniper]

I made one for my Twister from Iroko. I followed the procedure in Larry Pardey's excellent book 'Principles of wooden boat building'. Basically, joints are butted, with silicon bronze rods holding the sections together. Holes for these rods are drilled to exact diameter; expansion of the wood holds them absolutely tight (although I plastered plenty of epoxy around for 'belt and braces'

pm me if you want a copy of the article I wrote about this for the Twister mag.

 

[Mirelle]

Excellent advice

I had forgotten that wonderful book. Anyway, I agree.

 

[Peterduck]

You do not say what size of boat you are making the rudder for. A 3" x 3" rudder post sounds like it's for a sizeable cruising yacht. A stainless steel rudder post may be a better proposition than a wooden one. These can be subjected to some pretty horrendous strains, and it is something that you want to be completely confident about. From memory, the rudder post on my 36ft gaff ketch is about 40-50mm diameter stainless steel, socketing into a cast bronze fitting on top of the rudder which holds the rudder blade bolted between two straps. A similar fitting at the foot of the rudder holds the heel pin. The blade is made of several planks of jarrah butted to each other on edge and fixed by half-inch copper through bolts from leading to trailing edge.