After the previous owner accidentally damaged the shaft with a faulty ShaftLok system, I decided it was necessary to replace the whole thing. After-all, we were no longer in need of the ShaftLok system since we now have a feathering propeller. In the photo here you can see how the, now cut ShaftLok, had been rubbing on the shaft and removed approx 15% diameter (38mm down to 33mm) in a small area.
Structurally the shaft is reduced in strength a good deal more than 15%. I won’t go into details but given the forces involved, especially since we are now running a large 4 bladed Variprop, it needed replacing.
Removing the Shaft
A shaft is for life and “should” outlast an engine. As such, many boats are not designed for easy prop shaft replacement and as was the case with our Seastream. The shaft is 6ft long and when drawn out aft, it butts up against the skeg. The P-Bracket is incredibly strong and would not flex an inch to squeeze it past. The engine had to be lifted!
A quote from the yard was £3500 to do this when they assumed the job would be problematic and time consuming. However, Ian Anderson designed the saloon very well to give 360 degree access.
Once all the boards are up then you have the issue of somehow lifting the engine. Rigging a large A Frame was a possibility but we soon noticed that the main sheet track runs directly above the engine. After removing one of the saloon headlining panels we discovered a perfect place to fix an M10 Eyelet. The rest was easy. A chain hoist and a few things disconnected such as the Aquadrive unit and engine exhaust, and it was up by 2 ft with in 15 minutes. The shaft slid out forward and then the engine is lowered back into place.
Whilst the new prop shaft is being made I sent the AquaDrive away for a service even though it wasn’t causing a problem.