The steering mechanism on a narrowboat is very simple. A tiller connected to a curved ‘s' shaped steel bar, known as a swan neck, fits into a flat rudder protruding out the back of the boat. To stop the tiller wobbling, there's a top bearing at the base of the swan neck where it joins the protruding rudder.
What can go wrong?
Catching the rudder
One of the more common and frustrating issues for boaters is catching the rudder, which often results in the vessel becoming difficult to steer. At River Canal Rescue, we call this ‘popping out of the cup', as it refers to the rudder lifting out of its locating joint.
While such lifting out is rarely damaging, it can be difficult to re-insert the rudder once dislocated. If damage does occur it usually affects either the skeg (the support beam extending from the bottom of the boat), or the top bearing (responsible for ensuring your steering has a smooth operation).
Unfortunately, there's nothing you can do to avoid damaging the skeg, apart from being diligent and ensuring you position your vessel correctly in the lock.
The rudder shaft is worn
The shaft in particular can wear out if it's a split shaft design. A split shaft design has two sections - a hollow square profile tube fixed to the bottom half and a solid square profile shaft fixed to the top half. If you experience lots of play in the steering (having to move the tiller before it moves the rudder), the shaft may be worn and need replacing/repairing.
