the tiller-rudderhead bearing and carrier usually have the main casting of cast steel,with a large machined base for fitting to the deck. A bronze thrust ring is on top of this casting and the tiller boss has a machined ring face to go against this thrust face. The thrust ring is in halves and dowelled against rotation lubrication is provided. The main gland bush, in halves, is usually of gunmetal and grease lubricated