Custom Gudegons
For the past few days I've been making new gudegons for Maiwar.
A fair bit of thought went into the design of the rudder. There were a few criteria I had to meet to make sure I had the best rudder possible. Firstly, it had to be lightweight but strong; secondly it had to be traditional in appearance; and last, it had to be able to lift up above the level of the keel, and still function when raised. This last bit was the trickiest.
The arrangement I've ended up with compromises 4 gudegons and one long pin, as opposed to the standard pintail and gudegon arrangement. When navigating shallow waters, such as that of Moreton Bay, a lifting rudder is essential. The long pin means that the rudder is free to slide up and down as it wishes. To pull it up and lock it in a certain position I have a line that runs from the rudder chek up through a turning lock on the side of the stem, and back to a tufnol cam cleat mounted on the aft coaming. With this line I am able to raise and lower the rudder at my convenience.
The pin is 10mm in diameter. I originally bored the holes in the gudegons at 10.5mm, assuming this would be enough. Indeed it was enough for the rudder to slide up and down freely. However, I wasn’t getting enough degrees of movement in the rudder. It depends on the boat, but 36 degrees is about optimum. I was only getting about 25. This is due to the fact that the sternpost is curved, and the gudegons are mounted at different angles to each other, as opposed to being both square to a straight sternpost. This means that when the rudder is turned the gudegons bind up on the pin. To remedy this I had to bore out the gudegons on the rudder to 12.5mm.
I will admit that the rudder now has a bit of play in it, more than one would like if they were to be used on a yacht. However, for Maiwar, it’s just fine.
Originally I bought 'off the shelf' gudegons and used a length of 8mm rod for the pin. I thought it seemed strong enough However, two boatbuilders whose opinions I respect greatly both said that they are too light for the job.
Making the new gudegons was a simple process.
I ordered a length of 3mm x 30mm 316 stainless flat bar, and a length of 20mm round bar.
The first step was to cut to length the straps. Then it was a process of heating them up in the middle till they were red hot and, using a hand on each end, bending them around the 20mm rod till they touched each other on the other side. After this I cut the straps to their final length and rounded the ends. The round on the end of a steel ruler looked pretty nice, so I used that as a guide.
Next I cut the 20mm round bar into four 30mm lengths. I then realised that I would need to put a filler piece behind the round bar so the opposing gudegons wouldn’t rub against the stem and rudder. For this I found some leftover 6mm plate and cut it into 20 x 30mm pieces.
I had then done as much as I could, it was time to pass it onto someone with more skill than I in the metalworking field. So I jumped in the car and drove up the highway to a friend's place. Nick is a cool dude with a lifetime spent mucking about with boats. He spent many years as a blockmaker, crafting traditional wooden blocks for some fine yachts around the world.
Nick has a lathe and can weld stainless - a very good friend indeed!
With the lathe we bored out the 20mm round bar. Then he used his stick welder with stainless rods to glue it all together. After a grind and a bit of a polish I was ready to drill some holes and try it all out.
The system is a success. I've got my 36 degrees (roughly) of movement, and the rudder moves up and down freely. I'm now confident it'll all be strong enough for a trans-Pacific journey!
