miket
Well-Known Member
Following on from my posting a few weeks ago where I broke a flexible coupling on one engine, without hitting anything, and concluded that it was caused, probably, by engine/ shaft mis-alignment, and resulted in a bent shaft (top end) a broken casting on the end of the gearbox, plus....
I have submitted an insurance claim, yet to be determined, and following investigations by the assessor, and the coupling being returned to the manufacturer for comment, the likely cause may be different to our initial thoughts.
The boat is a Broom 37, 1992 with Volvo TAMD61A's (306hp).
The coupling manufacturer made 2 observations:
1. Wear in 3 of the 6 holes (elongated) on an adaptor plate, joining flexible coupling to gearbox indicated that these 3 bolts had been loose and eventually broke, at which point the rest decided it was all too much.
2. The flexible coupling fitted was a little under (10%) their acceptable tolerances. They admitted that their tolerances were very conservative and based on use by commercial fishing boats.
I would venture to suggest that in the light of my experience, fortunately all of which happened at low speed and not the 20+kts we were doing 10 minutes earlier, it may be worth checking, or having checked, the bolts securing your flexible couplings. Generally speaking, all reasonably current inboard powered boats have them.
I would like to thank Broom Boats (Andrew Stone) who couriered a replacement coupling to me in Belgium within 24 hrs of my asking. Also, a short and rather stout engineer in Nieuwpoort, called Mr Vandeweghe, who with his friend Chritian, somewhat less stout and able to squat in the back of the Broom's engine bay for about 3 or 4 hours, who put everything back together again the day that the coupling arrived. (unfortunately to little avail, as the shaft was bent sufficiently for him to advise only using for close quarters handling).
Hopefully, Haven Knox-Johnston, for at least contributing a large part of the repair cost!
I have submitted an insurance claim, yet to be determined, and following investigations by the assessor, and the coupling being returned to the manufacturer for comment, the likely cause may be different to our initial thoughts.
The boat is a Broom 37, 1992 with Volvo TAMD61A's (306hp).
The coupling manufacturer made 2 observations:
1. Wear in 3 of the 6 holes (elongated) on an adaptor plate, joining flexible coupling to gearbox indicated that these 3 bolts had been loose and eventually broke, at which point the rest decided it was all too much.
2. The flexible coupling fitted was a little under (10%) their acceptable tolerances. They admitted that their tolerances were very conservative and based on use by commercial fishing boats.
I would venture to suggest that in the light of my experience, fortunately all of which happened at low speed and not the 20+kts we were doing 10 minutes earlier, it may be worth checking, or having checked, the bolts securing your flexible couplings. Generally speaking, all reasonably current inboard powered boats have them.
I would like to thank Broom Boats (Andrew Stone) who couriered a replacement coupling to me in Belgium within 24 hrs of my asking. Also, a short and rather stout engineer in Nieuwpoort, called Mr Vandeweghe, who with his friend Chritian, somewhat less stout and able to squat in the back of the Broom's engine bay for about 3 or 4 hours, who put everything back together again the day that the coupling arrived. (unfortunately to little avail, as the shaft was bent sufficiently for him to advise only using for close quarters handling).
Hopefully, Haven Knox-Johnston, for at least contributing a large part of the repair cost!
