STERN TUBES

You may wish to fabricate your own fibreglass stern tube – if you know a bit about fibreglass, it is not difficult and a fibreglass stern tube in a fibreglass boat is the obvious way to go.   Study the illustrations shown here and this will give you a good idea of how this can be accomplished or follow details given in your plans.

SAILBOAT RUDDERS

The first step in making the rudder is to make a template of the shape using the measurements and other information shown in your plans, plus some check measurements taken directly off your boat.   The pattern should allow for the top and bottom bearings and is best made from ¼” [6mm] hardboard or plywood.   The rudder stock should be made from 316 grade stainless steel and may be solid round or heavy walled tube. Your plans should give you recommended sizes or you should consult a qualified marine engineer.   When welding the tangs to the stock, be very careful not to distort the stock by applying too much heat in any one area so make sure the welding is undertaken in a progressive manner to minimize the chance of distortion.   The rudder core may be made of plywood, timber or foam or a combination. Foam has the advantage that it is easy to shape and any water that may seep between the fibreglass and steel shaft will no effect.   When the core is in place, dress off the rudder to its desired airfoil shape.  

   Lastly, you will install a heavy laminate of fibreglass to the entire rudder.  It is important to achieve a good seal where the fibreglass meets the steel shaft.  Epoxy resin would give the best bond between the fibreglass and the stainless steel although most rudders are still made using polyester and foam as any water inside would have little effect.