Gearbox advice?

[Fingal]

Out for a wee drift and sail today, and when the wind died as it so often does on these autumn days, we started the engine. It's a DV36 Bukh with a standard stern drive and while the engine was running nicely, nothing was happening in the propshaft area. The linkages are complete and the gear lever on top of the gearbox moves normally, but nothing else happens. The shaft can be turned by hand, there are no unusual sounds when the output shaft is thus turned, there is enough oil of the correct grade.....
Any advice from anyone who has experienced a similar failure would be welcome.

[Arghiro]

As no-one seems to be talking to you, I shall relate my experience with a completely different boat, engine & gearbox.

Volvo MD2b with Monoshift, changed gear & it got stuck in reverse, everything outside the box appeared normal, shifter moved, cable moved & gearbox operating lever moved - but it stayed in reverse. On dismantling it I discovered that the actuating lever INSIDE the gearbox had broken. Wasn't expensive or difficult to fix.

Hope yours is as easy to sort.

[Rowana]

I don't know the particular engine or gearbox, but I'm with Arghiro on this. If everything outside the box is moving as it should, then something inside the box is either broke or has dropped orf.

Can you take the lid off the box in situ, or is it a remove and strip down job?

[cpedw]

A single cylinder Bukh we owned 20 years ago was very sensitive to adjustment of the fwd/rev gear lever. The cones were very picky about engaging, apparently due to age and neglect.

Derek

[Gardenshed]

Bukh UK (01202 668840) were always great whenever I've needed help or advice. I think the guy that I spoke to was called Norman. Instant recall of spares numbers and good suggestions on what to look for/what to do to avoid further trouble.

[sahona]

Thinking retrospectively, were there any hints that something was in the offing? I realise you haven't lived with the setup for long enough to know every squeak and click, but sudden total failure doesn't sound right to me.

I sincerely hope the previous owner didn't sell you a boat with a "get-you-home" fix installed.

[marisca]

I believe the OP is considering returning his sterngear to a configuration closer to the original design, particularly in respect to the number of bolts employed to connect the gearbox output bit to the whirly bits. Next thread could be about surveyors and surveys, methinks.

Only one person wants to see the pictures so far.

[Fingal]

The normal arrangement of 4 bolts through the gearbox output flange had been reduced to a single bolt which unsurprisingly sheared eventually. We can only suppose they fell out one by one.

The flexible coupling is under a screwed down cabin sole and fairly inaccessible so it's not altogether surprising that no-one knew things were not as they should be. I suppose one could attack the surveyor for not finding this but he did point out a wide range of other matters needing attention. I had had inspection of the drivetrain couplings and checking engine/shaft alignment near the top of the maintenance list for a week or two but the lack of a round tuit in my toolbox, and some very nice autumn sailing days got in the way.

The maintenance schedule now has an additional item under monthly checks: Condition and security of driveshaft couplings.

I would love to see the photographs, myself.