So the plan is to use the Prindle 19 hulls as floats, or amas, for the trimaran. Some of the advantages to this are, nice smooth profile, no hard chines, very efficient shape and the option to use the centerboards in light air or at low speed. I have seen a build blog where the builder found the boats goes sideways easily at low speeds. This means I don’t have to potentially increase the profile of the main center board and change the shape of the centerboard box.
On the other hand, the cross beam attachment points on the hulls are about 4″ different from the tri plans. The Prindle cross beams are bolted to the deck with two bolts each and I don’t feel this will be adequate for a boat that weighs 1000 pounds instead of 400. Adding to failure concerns, is the fact that these cats have been known to snap the bows off! The later models had horizontal bulkheads in place to stiffen the hulls. I am hoping to use a stud sensor to determine if mine has these but I may have to get a camera up inside.
To attach the Scarab arms I will have to cut into the decks and build up better attachment points. While I have these open I will make sure that there is enough reinforcement inside.
The hulls are 19 feet long where the plans call for closer to 21 feet. So to increase the length of the float, and to make the shape of the stern to match the stern of the main hull I will add 16″ on the stern. This keeps the mounting points in the right location.
The lower volume of these floats will make the boat more likely to heel over in a big gust instead of flipping over the lee float.