GRP hull modifications

[JacoT]

So I have/had made my mind set on a steel hull project boat as a live on a bluewater cruiser. I came across a 36 Corrida GRP that is perfect for several reasons and not for others (As I have quickly learned, the perfect boat does not exist).
#It currently has a sail drive config.Can the hull be modified for an inboard Yanmar and what will the compromises be ?

#I want a boat that can enter shallower waters .Can the keel be modified and how ai. bolt on vs moulded GRP And w2hat will the compromises be ?
Attached is a photo of hull and part of keel

[JacoT]

Photo does not want to attach...

[Stumble]

Can it be done? Technically yes, it is possible but the scope of the renovations necessary to fit it all would be pretty monstrous.

To switch from a sail drive to a shaft drive... is problematic. The prop really needs to be kept in generally the same place, so you will need to move the engine forward quite a bit. Then drill a 1-1.5" hole in the bottom of the boat likely thru parts of the keel or keel sump, build out a new engine mount... This is an enormous project, likely to cost more than the boat is worth.

Cutting down the keel. Again technically possible, but you need to replace the lost RM. The formula is RM=m*d where m is mass and d is distance from the center of buoyancy. So Not only do you have to add back the weight you remove, you also need to add more to make up for the shallower keel. How much total just depends on the amount removed and the draft reduction.

But you have to keep the total mass of the boat below the designed max displacement or you can induce other issues.