Hi everyone,
We are faced with trying to replace our rudder bearing because the marina we are hauled out at does not have service people available for weeks. The whole problem started in the Bahamas where we hit a reef at Devil’s backbone ( Spanish Wells) and got hauled out there with repairs done. The workers were great but we did not notice that the rudder bearing-was sticking out of the hull more on the repaired side. We picked up a new rudder in Florida on our way home to Virginia Beach.
So we are going to try this ourselves. Anyone with words of wisdom?
It’s reasonably easy..
But…
The rudders have to drop the length of the rudder stock. Probably about 500mm
You may have to be lifted to get enough clearance.
Thinks to watch..
The autopilot rudder arm. Be super careful. Unscrew this first. We didn’t detach it from the arm, but we were very careful.
Have a Philips head screwdriver handy to put in the hole that the locating pin is removed from. This stops the rudder from dropping.
Have some carpet under the rudder so you can rest the rudder without damaging it.
The rudders are heavy.. probably about 30kg.
Polish the area that the bearings running on.
This will improve the life of your new bearings.
Most rudder bearing plastic swells a little when immersed in water. This makes a perfect fit very difficult. They don’t want to be too tight before you are splashed.
We used a piece of scaffolding, slid into the rudder stock tube to knock the bearings out. They took a bit of a thump, but came out quite well.
The old bearing will be either loose, held in with sikkerflex or held in with epoxy. This depends on who put them in last time.
Moisture.. you can buy a drywall moisture meter. A non contact type. You can buy one from most hardware stores. With this device you can check the rudders to ensure there is no water inside them. If there is, you are best to open the rudder and repair the damage.
We have not had to do this ourselves - but in Trinidad they dig a hole in the ground under the rudder to enable them to drop it - cheaper and easier than an additional lift. Obviously that very much depends on what sort of surface you are on and if it would upset the marina…
If you are planning to do the bearings, it is possible to have them all set to drop prior to being lifted. Then you can drop the rudders when you are being setup on the hard.
Then refit the rudders when you are being lifted to splash. That’s what we did last time.
It really only takes a few minutes to drop the rudders.
Does anyone know where we can find the replacement part in US for rudder bearing. I see the diagrams on this forum.Our boat yard is looking to source the correct part
RUDDER BEARING REPLACEMENT For Knysna 500se we are hull#95. I wanted to share the information we received from Kynsna as well as other owners on bearing replacement.
From Carel at Knynsa Service Department:
I have attached a GA Drawing of the rudder bushes and removal procedure. On previous experience if have asked them to cut the inside diameter of the vesconite bushes the same as the specific rudder stock as some of the outside diameter of the rudder stock is different. When the rudders are removed it’s quite easy to do. You need to clean the rudder stock when removed as some debris usually get stuck on it. See attached Rudder Removal Process from Knynsa and the drawings.
The bearings are made from a product called Vesconite.
The company’s website in Australia is: www.vesco.com.au
I do believe they do international shipping. They have tubes 120 x 70× 500mm - this is enough material for 4 bearings.
I hope this helps. Thank you to the entire Knynsa community for all this valuable input!
