This short 1/2" diameter pintle is used at the top of a standard fiberglass rudder. The long bottom pintle installs into the transom gudgeon first and the short top pintle installs second. The bolt holes in the new pintle are intended to align with the holes in your old rudder. But since the rudders are hand made, variation in thickness sometimes introduces a variable that causes misalignment. It may be necessary to fill the holes in your rudder with epoxy and re-drill (see "May we also suggest" below).