Moulded tiller 2011
The aluminum tiller on Jocker works fine but is too low for an old bugger like me. So I decided to make a new one. The best way would be to bend aluminum tubes and weld it. Stiff and simple. But I cannot weld aluminum. So I made myself a moulded tiller. Also stiff but absolutely not (!!) simple. Don't try this at home!
I have made a mould from wood and PVC sheets which was a hell of work and I swear I would never do that again. As I cannot recommend this I just show the result. Some of my friends say this is a 1960s vision for a spacecraft design ...
At least it is unique and works fine. Weight is 2.5 kgs
Rudder needle bearing / SELFMADE
The boats are originally equiped with bearings from JP3steering systems.
An alternative is Jefa from Denmark. I decided to make the bottom bearing by myself and avoid complicated work on the hull
The part looks like this when it goes into the boat: The original part is not produced any more. A similar part is 10.14.07
To take it out you have to remove the inner tube that is laminated to the hull. With some luck you can wind the big nut off. I did not have that luck!
I had to cut the nut off. Then I removed the plastic ball inside and made a new one from POM. Make sure that you use a material that does not swell in water!
The rudder shaft is very sensitive to corrosion. Avoid any materials that are more "precious" than Al. My shaft went oval throughout the years so I had to shape it back to cylindrical with a file. If you have no experience with that, find someone. Do not try yourself!!!
The aluminum cone is held in the hull with an epoxy ring and 2 srews from underneath. So I do not need the nut anymore.
This system worked fine for 1 year and then I decided to make a needle bearing (It would have worked another 10 years, but I HAD to improve it.)
Why a needle bearing? To avoid the stick slip effect, especially when you squeeze the boat with the kite up?
Why a ball? The boat is very likely to be twisted when under power. So the angles of the deck and the bottom of the hull alte, which will caus friction in the bottom bearing. Furthermore most boats are not being built very precisely. Some people see a reason in a bending rudder shaft. But if you calculate the required forces to bend a 67mm aluminum shaft in a significant manner, you might come back to the twisting hull.
I took everything out again and turned 12mm dia from the inside of the ball. 5 mm in length I kept the old dia so that the needles do not fall out.
Then I made a cage for the needles from POM. The width is 6.5mm with a distance of 15°. This was a bit difficult and took some 2 hrs.
The needles are made of PAI (Torlon) Extrusions. The raw material is 6.8mm and will be ground precisely to dia 6h7 in pieces of 50mm.
Monday, Feb 15th 2010
Today Santa Claus spent a late visit and brought the Torlon needles for the bearing. I instantly had to put them in.
This is the "dry" setup in my cellar:
On the bottom you can see the epoxy ring that holds the alu cone in the hull. Also there is a tight distance ring on the shaft.
When the ball is in final position it looks like this:
The ball went on without any play and you could imagine me grinning when I made the ball turn with a slight fingertip and it remained turning for a while. YESSSS!
Cost: 120 EUR (Torlon)
Time: 6hrs (on the turning machine)