By Tom Pawlak — GBI Technical Advisor

A typical spade rudder for sailboats is made up of two fiberglass skins that define the shape of the rudder, a metal mandrel that is an extension of the rudder post, and foam core which bridges the space between the skins and mandrel. In order for a rudder like this to work properly, its fiberglass skins must be attached to the core and the core must be attached to the metal mandrel. Side loads on a rudder exert compression loads on the core which transfer into the mandrel. If the components become detached, the rudder can deflect excessively and eventually develop cracks in the fiberglass skins. Continue reading →