In the third of our three blog articles on rudders and steering systems, we look at how to replace rudder bearings and repair a water-saturated core.
How to replace rudder bearings
These are the steps involved in replacing the rudder bearings of a typical spade-type rudder:
- Find out where you can get the replacement parts in advance of doing the work as this may take some time. If you need to arrange for parts to be machined it will be necessary to take measurements after the rudder has been removed.
- Work out how much clearance from the hull bearing to the ground will be required in order for the rudder to be dropped clear of the hull.
- Try and find out how heavy the rudder and shaft will be – rudders can be surprisingly heavy with most of the weight being in the rudder stock.
- Discuss your plans with the boatyard and decide how much assistance you will require to remove the rudder.
- Support the rudder blade from beneath before you start disconnecting it. One way to do this is to make a support using a canvas tarpaulin tied with ropes to port and starboard deck cleats rope cradle or winches.
- If your boat has wheel steering, disconnect the steering mechanism and remove the quadrant.
- With the rudder blade supported unscrew the collet that holds the rudder in place.
- Lower the rudder gently to the ground.
- Remove the old bearings by sliding them off the shaft. These are often made from a very hard wearing engineering plastic known as polyoxymethylene (POM), commonly referred to as Delrin. Note: plastic bearings on small yachts tend to be plain bush type bearings. Yachts over 10m tend to have roller type bearings. Take expert advice on which type you will need.
- Take accurate measurements of the rudder stock and the shaft to be sure of the internal and external measurements required for the new bearings.
- Slide the new lower bearing onto the rudder stock before refitting the rudder.
- Ask the boatyard to help with lifting and refitting the rudder.
Repairing a water-saturated core
While replacing rudder bearings is not overly challenging for the average DIY boat owner, more major repairs to rudders are not so straightforward. Here are the basic steps involved in repairing a rudder with a water-saturated core:
- The first step is to drain out the water from the rudder by drilling a number of holes at the base of the blade.
- The seam of the rudder blade is cut using a circular saw and the two halves of rudder are separated. If the rudder is foam filled, this can be removed. Now the damage can be fully assessed.
- The condition of the frame and stock need to be checked over. If the framework is badly corroded then this will need to be replaced with a new one that will need to be welded to the stock.
- The void will be filled with expanding foam.
- The two fibreglass halves of the blade will be re-joined using thickened epoxy for maximum strength and laminated together.
