Engine placement question

I recently pulled my engine in my fish Nautique and replaced engine stringers, engine bay bulkheads and anything else that I could get to with wood core. I got new engine mounts and sett everything as close as possible to what it was. Dropped my engine back in and I'm sitting about 1/2 farther back. I can tell by the marks on shaft. It would be a real pain at this point to try move engine 1/2 forward so my question is any problem with leaving it where it is?

Awesome! After I tightened everything up its more like 3/8". Here is some pics of my project. This is my first major fiberglass restoration project so lot of learning but I feel everything is much better then factory.




Cut the top of first stringer off. Stringer Popped right out with pry bar.

I cut the top off the stringer and removed wood left everything else to hold new pvc stringers in right place. Sanded and cleaned out stringer area real good and mixed up a nice batch of thickend epoxy with cabosil to glue in new stringer. Got that set where I wanted and poured thickend epoxy to fill rest of voids. Then I went over it all with 4 layers of 18 oz cloth with epoxy which was probably over kill. I also removed those bulkheads and realized how much work I was getting into.

Tore out wet wood around the rudder and replaced with pvc and 3 layers 18 0z and 1 layer 1708 in between

Some 545 epoxy primer




2 part poly topcoat. The bigger holes in the top of bulkhead are for access to thru bolts for the console. An aluminum backing plate was also added for console.

The work that guys do on this site to keep these boats running is purely amazing to me. Very nicely done!!!!

Fl Inboards wrote: 1/2"farther back make sure you have propeller clearance with the rudder especially if you modernize your propeller with an ACME. Another option is to cut a 1/2" from the coupler end of the shaft and re dimple the shaft where the set screws go, there should be enough key way to support up to a 1/2" cut off. .

Jody,
Excellent point. I'm glad you thought of it.
Cole,
I'd cut off the prop shaft even if you have the clearance to the rudder. You don't want to increase the overhung load on the cutlass bearing, strut as well as the shaft. The rule of thumb clearance between the strut and prop is one shaft diameter. I know Tim likes to go less and I agree with him.

I sure wouldn't worry about less key and keyway considering about 85% or better of the torque is transmitted to the shaft via the heat shrink/press fit of the coupling.

Went out and measured the distance between prop and strut and I'm at 13/16". Still haven't tighted up the coupling bolts so I might get another 1/16. So they must have had it way to close before. Im going to try finish everything putting everything back this week so I can run the boat next weekend. I'll let everyone know how it goes. Also appreciate everyone on this site couldn't of done all this without all of you!

All Shamrocks have double nuts, if the Fish's shaft is long enough to have 2 maybe they did from the factory also. The only thing wrong with his is the one touching the prop should be the thinner jam style.

Cole,
Stainless to stainless galls and locks up. This is the case when you use a stainless nut on a stainless prop shaft. Many have found out the hard way. Eddie (backfoot) just recently had the problem and posted the issue in his American Skier repair thread. I too had the problem when I purchased my Tique. Eddie as well as myself were able to save the shaft by carefully cutting the nut in several spots, expanding it to get it off and then chasing the threads with a die. Have you had the prop off? By your wording it sound like you have so you may be lucky. I wonder why the prop sits so far up on the taper? It could be that at one time it was damaged and when the prop was repaired the prop shop re reamed it making the taper larger? I highly recommend getting the prop off and replacing the nut. As mentioned, a brass washer can be used as a spacer or use a nylock brass nut. I also recommend Lapping the prop to the shaft.

Yes I have had the prop off. I actually had this shaft made couple years back by Stuart propellar. It's been a while but I think they just made it the same as what was there. The propellar is acme and only 1 year old and I bought new from acme so I hope it wasn't repaired lol. The old federal prop sat in the same spot. I will pull the prop, replace nuts, and lap prop.

Very nice work

Great job on the stringers, I hope to someday get the time to clean up my bilge and do my repower. Time is such a hard thing to come by. haha
another option over pvc for some of the smaller coring jobs like the rudder post and such is FRP. (not the stuff on your shower wall) They sell it in mcmastercarr in the same shapes and sizes as you can buy steel and alum. I love the stuff, and its is amazing to work with. check it out.


The prop nut discussion. haha
Contrary to what most say and everything you have seen in the past the large nut is designed to hold the prop and the smaller one is designed to be the "locking" nut on the end.
The crazy thing is if you take a walk around any boat yard and 90% of them have it wrong. and still have no failures.

DayTony wrote: Contrary to what most say and everything you have seen in the past the large nut is designed to hold the prop and the smaller one is designed to be the "locking" nut on the end.

Except when the guy who built your boat tells you to install the thin nut first and has the documentation to back it up.

Gary S wrote: DayTony wrote: Contrary to what most say and everything you have seen in the past the large nut is designed to hold the prop and the smaller one is designed to be the "locking" nut on the end. Except when the guy who built your boat tells you to install the thin nut first and has the documentation to back it up.

Yes, from an engineering standpoint, you want the load on the regular nut since it has more thread contact than the thin jam nut.