Cruising Cat with Shaft Drive

[Whimsical]

Gludy doesn't talk to us any more

Mike

[videorov]

With them underwater all the time they go. Two years on a saildrive is
not long at all. Drive shaft will last much longer and less less problem.

[JerryF]

Endeavour Catamarans use shaft drive.

EndeavourCats Home Page

JerryF

[schoonerdog]

Umm, my saildrives have lasted now 10 years without issue. Knock on aluminum, but I'll readily concede that best of all would be a retractable drive.

[Captain Bill]

From personal experience, my issues with saildrives is from the maintenance point of view. I have had Yanmar saildrives for about 3 years. Despite having a tube that goes all the way to the bottom of the drive changing the oil is still a PITA that lasts several hours. The first half pumps out pretty quickly with a vacuum based oil changer but it takes several hours to get the rest out because it takes a while for the 90 weight to get down though the passages to the bottom. I have had one shaft seal destroyed by monofilament which required pulling the boat from the water. Fortunately or unfortunately I had to have the boat hauled anyway because the front main seal on the other transmission blew out. The issue is to service the transmission you must take the lower unit out of the hull. On most shafts I have seen you can disconnect the shaft from the transmission and the transmission from the engine to service it without hauling the boat. Some saildrives have worse reputations than others. The Yanmar SD-40 was in production only a few years before they were discontinued. Of course that is what I have. I don't worry too much about submerged objects because I have keels in front of my drives. The props I have have rubber hubs which are supposed to spin if the blades come to a sudden stop. It is my fervent hope that I won't be testing that feature. I expect that some day that rubber will deteriorate and become a maintenance issue as it has on several outboard props I have owned, but it sure beats ripping your engine off of its mounts (I hope).

I once hit a crab pot at night with a shaft drive. It broke the coupling and the prop slipped back and jammed the rudder. This meant going over the side at night to get the rudder freed up, rigging a line on the shaft to keep it from backing out into the rudder again, pumping the bilge from the now leaking shaft seal. I don't see how my saildrives could jam my rudder so that is in their favor. I also don't think it is likely that a fouled prop would cause a leak, though I suppose it could happen if you broke the engine mounts.

From my point of view Saildrives are not better or worse than shaft drives, just different.