Martin, this is what Mark explained to me and our head mechanic agrees
100%.

Typically the shaft coupler that connects to the tranny is a flange.
This is often held with a series of bolts around the edge. In the case
of a fouled prop, especially with a heavy line, the prop and shaft
become wrapped. The engine labors and if it's not cut in time some of
these bolts shear away. If enough of them shear away the forces on the
flange become uneven and the shaft begins to wobble a little or a lot.
The shaft will rarely be true after such an event and it can all occur
in seconds, well before an emergency stop How often does this happen?
When, according to folks I spoke to at my shop, they've seen it many
times, especially on older boats where the flange has seen plenty of
corrosion. They've seen it happen on powerboats as well.
The Drivesaver loads are far below those of the bolts on the flange
and would prevent this by breaking first.

I hope this helps, Martin. But if it doesn't please contact Drive
Saver and describe this scenario above to them if you have any doubts.
Unlike you I work closely with the largest full service yard in the
area, so I have real world insight into SOME issues.
I have no doubt that a lot of know-it-alls will chime in here, but
they are ALL full of crap. Call the company and talk to them yourself.

Cheers,


RB
35s5
NY