Drive Savers?

Lots of good thoughts here. Thanks.

A related dilemma is what to do about the shaft-to-transmission couplings. The flanges on the prop side are through-bolted and the bolt on the port side keeps shearing under load—possibly the result of some play in the keyway. I’m strongly considering replacing the flanges with proper split couplings, ideally while the boat’s out of the water.

But I’m not sure what I’ll run into with the black spacers that are between each coupling. Not sure what they are or why they’re there unless it was to replace some previously installed drive savers—or perhaps they’re some kind of vibration dampener? Anybody have these or seen anything like them?

angus99 said:

Lots of good thoughts here. Thanks.

A related dilemma is what to do about the shaft-to-transmission couplings. The flanges on the prop side are through-bolted and the bolt on the port side keeps shearing under load—possibly the result of some play in the keyway. I’m strongly considering replacing the flanges with proper split couplings, ideally while the boat’s out of the water.

But I’m not sure what I’ll run into with the black spacers that are between each coupling. Not sure what they are or why they’re there unless it was to replace some previously installed drive savers—or perhaps they’re some kind of vibration dampener? Anybody have these or seen anything like them?

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my old aluminum boat had something like that it they have plastic or fiber washers on one end of the bolts they isolate the shaft electrically

IMO drive savers are mostly for fast boats (10knts +(not trawlers) and they aren’t good for vibration reduction,
For a 15 knot cruiser they could be a good investment. And to install them it’s necessary to cut an inch or so off the prop shaft .... and can’t put it back on.

I had a spacer made for one last year when I got rid of the drive saver. The installation basically sucked since there was no way to get the drive saver out to replace it. The PO had so much paint put on the shafts that they will not slide in or out more than about 1/8”. So while I could remove the rear side of the bolts, there was no way to get the forward bolts out so I ended up cutting the bolts. Had a spacer made and after I pressed the old prop shaft coupler off I went with a new split coupler on the shaft. Put in the new spacer and all is good now. The spacer was a bit over $500 so it wasn’t cheap, but cheaper than a new shaft since the current shaft is too short due to the spacer.