This is a buddies boat but I was commissioned to do the work on the side of my usual job after stone crab season after he saw my last refit of my charter boat. I still have a while til it begins so I'm trying to get my ducks in a row so I can give him a fair quote especially since he is my good buddy. That means I'm trying to track down some of these parts like the longer shaft tube which isn't as common down here in FL. The boat is a 35 ft crabber/spiny lobster, made in the keys, hard chine and fairly light for it's size. Solid glass but is only 1/2 thick where I repaired the engine thu-hull last year. Looks sort of like a crusader but not sure who the hell built it. The engine is only a 210 hp cummins 6bt. 12 ft shaft though and the engine is very far forward in this boat with the rudder protruding aft of the transom about 4 inches. Kind of an odd setup from what I've seen but it is a money maker for him. I understand what you mean about shaft whip and I have a plan for that. There was a bearing when the keel was wet but I was tossing around the idea of putting a second cutlass bearing at the forward end of the shaft tube just behind the stuffing box but the 2 inch tube should give enough room to add a 1.75 shaft later. Duramax makes a cutlass with a little less material if needed. Only 1/4 inch more material than the shaft so if the whip was that bad then we could go up a little in shaft size while giving up some material on the cutlass. We are trying to stick with the 1.5" shaft for now though.
There will be a tides dripless seal with 2 water sources of water. One off of the engine right after the gear cooler and one off the heat exchanger forcing water into the shaft tube to lube and cool both of the cutlass bearings. Gear is a TD MG502-2:1 so the shaft isn't really spinning all that fast. I was actually trying to find a gear with a 2.5:1 ratio to spin a bigger wheel but stuck with what it came with, the 2:1 to save money. She is swinging a 24" wheel which is a little small but pushed the boat along nice before at about 13+kts, topped out at 17ish after the bottom job last year. Loaded he sees a 10-11kt cruise. It's an inshore boat so the small wheel isn't as big a deal and the load it is carrying is far less gear than you boys up north are used to seeing I'm sure.
I wanted the longer tube to accommodate a very clean cut after the glasswork is done. 2 more ft of the shaft tube stock won't add much to the total cost and should give me a good buffer to be able to work with. I am optimistic but I think this may add a knot at cruise after I fair the keel in. Right now it is square and about 4 inches thick! Not a lot of nice clean water getting to that tiny wheel. I'm gonna fix that though, it will at least be a little more efficient.
I'll try to snap some pics next time I stop by the boat.
