Transom Hole for Sterndrive

Dear All,
we are close to laminate a FRP boat and we are thinking of making the transom hole for the sterndrive "molded" instead of cutting it in. Since I never saw this procedure in the industry I´m wondering if there are other draw-backs beside the loss of installation flexibility (have to know in advance, which sterndrive will be installed). Any Comments?

 

Hi Oliver,

I don't see any particular reason why the cutout for a sterndrive could not be moulded in with the rest of the hull. But I also don't see much benefit to doing it this way. Every bend, corner or irregularity in the mould is another spot that makes life difficult for the lamination crew. You'd save an hour or so of marking and cutting the hole, at the expense of a few hours to make the protrusion in the mould as well as the extra labour to trim and fold the fibreglass around it. Possibly worthwhile if you're doing a lot of identical boats, probably not if you're just doing a few or if there are different drive options.

It would almost certainly be worthwhile, though, to cut out the transom core for a few inches around the edge of the sterndrive transom assembly, before you laminate, and use chop-strand mat to bulk it up to the proper thickness in this area. Having solid fibreglass around the drive cutout will only add a couple of pounds, but will greatly extend the life of the transom.

 

Matt,

Thanks for your comments. The idea is to have different protusions, and lock them into the mold according to the sterndrives we install ( usually Volvo, Mercruiser and Yamaha Hydra Drives). Maybe we could use a mix of both technikes: cut the core, install the protusion and fill the gap to the required thickness with chop strand matt, thus no bending of fiberglass is necessary..