YANMAR SD 31 impossible maintenance schedule

[GALAWA]

On my catamaran built in 1999, I have 2 YANMAR SD 31 saildrives.

YANMAR engineers have not cared to design the saildrive so as to make it possible change the gear oil while afloat. Afloat, it is impossible to remove more than 1/3 of the gear oil .

Unlike VOLVO sail drives which have been properly designed in this respect.

And worse, my YANMAR SD 31 maintenance manuals claim that the saildrives'gear oil should be changed every every 100 hours.
This is lunacy: There is now realistic way to take a 7 meters wide catamaran out of the water 4 times par year when cruising western Carabean waters. Let alone the expense for doing so if it were possible.

The request to change the gear oil an unrealistic every 100 hours affords YANMAR a confortable position if confronted with a warranty claim.

For standard YANMAR shaft drives, other YANMAR documents say that gear oil should be changed every 1000 hours. This is more realistic.

Failure to provide the means to change the saildrive's gear oil when afloat is
YANMAR engineers ' design blunder. But maintaining that the saildrive's gear oil should be changed every 100 hours is amounts to contempt for the customer.

[LLizzard]

In that regard, Volvo SD are designed better. Is it feasible to change to a synthetic lube to lengthen the service life?
Other than hauling, If you are concerned about it, I would change out the 1/3 you can at a shorter interval, say 75 hours . Some fresh lube is better than none. Then change 100% when you haul out. Is that's annually?