Replacing shaft/strut on Hunter 31

Sep 11, 2015
147
Hunter 31 Marina del Rey
The other day I had a docking line wrap around the propeller (while still attached to starboard) on my Hunter 31. The resulting tension bent the shaft and the strut, sent the propeller up and to starboard, denting (but not breaching) the hull. The back of the engine shifted slightly to port to compensate. Terrible. So, now I have to fix all this mess.

Local boatyards quoted $5,000-$7,000 to fix this (including marking up the price of the shaft and strut 3-4x), so I thought I would give it a try myself. I have already ordered a new shaft/strut from this website. I would like to ask for some hints on how to do it while minimizing time at the boatyard.

1. Should I uncouple the shaft from the gearbox while still in the water? I have a PSS so I think there is little danger in getting a water leak. This will allow me to straigten the engine and test the gearbox for potential damage.

2. When installing the new shaft, apparently it is better to slide it under the engine (seems like lots of work) so that the coupling stays put as it comes from the factory. The easier way is to take off the coupling. Is it really that hard to align the coupling perpendicular to the shaft in the boat?

3. What is the preferred way of positioning the strut in alignment? Do I just put washers/shims until I get it into the right position? Then is it just bolted or should it be glassed over as well?

4. I understand that the final alignment of the engine should be done in the water. Should I at least try to run the engine for a couple of minutes while in the yard to check the strut positioning?

Any other hints would be greatly appreciated. In particular, any parts that I may need, bearings, etc.

Thank you,
Pizzazz
 
Sep 15, 2009
6,243
S2 9.2a Fairhope Al
do a search in the archives on setting up the strut and shaft.....you may find it better to do all the work sitting on the hard ...everything you are trying to replace and repair is below the water line and that's a tough way to do the work....and you also need to while you are on the hard inspect the hull for possible damage to the hull ....if you have loss insurance it may pay for some of the repair.....
 
Nov 6, 2006
10,111
Hunter 34 Mandeville Louisiana
Almost always.. the strut will have to be re-aligned and shimmed and bedded into position; a very labor intensive undertaking..usually a new shaft coupling will have to be used to get a correct fit on the shaft. If you search the forum for "strut replacement" and "coupling replacement" you should find some great info on the processes necessary to re-align these components.
Most folks, after getting shims correct, coat the strut base with grease and bed it in thickened epoxy. The grease allows for future replacement by keeping the strut base from sticking into the epoxy.seems like labor should be in the 20 hour range ..
 

SFS

.
Aug 18, 2015
2,088
Currently Boatless Okinawa
I have a 1983 H31, and had a new shaft, coupler, and strut put in last October. The shaft and coupler were less than $500, the strut was fabricated using the old one as a model for about $500 (the strut I ordered from here did not fit - wrong shape to base, and wrong hole pattern, so I hope yours works. Dave was wonderful about taking mine back.) Labor was less than 20 hours, so at $100/hr, your yard's estimate seems high to me. All my work was done on the hard, except for the final alignment in the water.
Good luck.