Rudder with filler.

by Dermot Tynan in Microtransat

Posted on Monday, September 23, 2013 at 08:00

Rudder with epoxy filler

This is a quick photograph of the rudder stock once it was filled with a mixture of West System 405 microfibres and West System epoxy. I formed a basic mould out of wood, added "shrink wrap" to prevent the filler from sticking to the mould, dropped in the rudder stock frame (see below) and then poured in the filler. It took around a week to fully harden, and I will sand and paint the finished product.

It was formed around a brass stock which you can see here:

Bronze rudder post

The rudder shaft is an 8mm brass rod bent into an 'L' shape. It is reinforced with 4mm brass rod soldered into the above pattern. All of that is then moulded into the finished product.

The biggest concern here is that the rudder shaft will lose traction inside the rudder, due to the torque of the motor against the rudder surface. If that happens, the rudder will swing back and forth with the current. By utilizing an 'L' section and then adding additional reinforcements, the rudder should be prevented from slipping. It also helps that the stepper motor controller has an adjustable current limit, which translates into an adjustable torque limit. The stepper will slip before over-torquing the rudder. That's the plan, anyway.

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