Q. I am unsure of whether the underbody of my yacht should be declared as a ‘Type 3’ (fin keel with a separated spade rudder) or ‘Type 4’ (fin keel with a skeg rudder). Please elaborate.
A. The critical detail that would imply a ‘Type 3’ underbody would be the fact that the rudder is a free standing spade, with little or no fixed skeg area forward of the rudder. In contrast, a ‘Type 4’ underbody features a skeg hung rudder, typically with a pintle and gudgeon type bearing near the rudder tip, and with a substantial area of fixed skeg forward of the rudder. The presence of a shallow ventral fin (sometimes termed a ‘fence’, or ‘bustle’, or ‘skeg’) such as those typical of IOR or International Rule yachts without a fixed skeg area over most of the depth of the rudder does not qualify for a ‘Type 4’ underbody designation.