Trojan Boat Forum

I've always been told and read that the jam nut (half hieght) goes against the prop then the full size nut after. Without getting too technical, this has a lot to do with thread loading etc., so say standards and technical data. In short the jam nut (small) is torqued against the prop then the large nut torqued against the small nut distorts it slightly. The combination keep the two in place. In fact, an old sod once told me that the propper way to install a prop is to tighten the prop on the shaft with the large nut first, then pull the nut off, put small nut on then large, then cotter pin if applicable. Yet if surveying all the boats in a given marina, I'm willing to bet 99% of them will be the other way around, even coming that way from the boat manufacturer. What do you guys think?

The old salt is correct.

+2

thin nut first then large , may are put on wrong . now heres the but , I have seen props come lose many times and 50% of the the nuts were right and 50% were wrong . in other words if you got it wrong don't worry about it . I know one pro that I totaly respect that will not put the thin nut first.

Would like to know his reasoning for doing it that way. Most boat manufacturers do it that way too. Not to say they do everything right though (ain't that the trueth)

jam nut first then a castle nut with cotter pin



Henry