eebygum
Well-Known Member
Mole Grips around the shaft if you have easy access
Propeller shaft brake
- Thread starter lowlander
- Start date
dansar
Well-Known Member
Hi
I asked the question back in October last year and received numerous replies.
Since then, I have re-engined the yacht and now have a Perkins M92B connected to a PRM 'box. Prm state in their manual that their 'boxes have been designed to ensure that prolonged trailing (free wheeling) of the prop will not harm the transmission. The prop is allowed to turn with the engine shut down and is therefore well suited for use in auxiliary yachts.
Having sailed on many yachts over the last 30 years, I have come across various owners/skippers stating what is good or what is bad for the gearbox. When under sail with the engine off, some allow the prop to turn. Others engage astern gear. I think a good answer would be for anyone who is concerned about this problem then contact the manufacturer of the gearbox with full details and I'm sure they will help.
There is no whine from the gearbox but that could be because it's new.
Hope this helps.
David
I asked the question back in October last year and received numerous replies.
Since then, I have re-engined the yacht and now have a Perkins M92B connected to a PRM 'box. Prm state in their manual that their 'boxes have been designed to ensure that prolonged trailing (free wheeling) of the prop will not harm the transmission. The prop is allowed to turn with the engine shut down and is therefore well suited for use in auxiliary yachts.
Having sailed on many yachts over the last 30 years, I have come across various owners/skippers stating what is good or what is bad for the gearbox. When under sail with the engine off, some allow the prop to turn. Others engage astern gear. I think a good answer would be for anyone who is concerned about this problem then contact the manufacturer of the gearbox with full details and I'm sure they will help.
There is no whine from the gearbox but that could be because it's new.
Hope this helps.
David
npf1
Well-Known Member
dansar - FYI and don't know if it's soemthing you've already thought of, but I read something recently about using a freewheeling prop as a generator whilst underway. I think it was using a low RPM alternator. Seemed like a good idea to me.
DaveS
Well-Known Member
I have a VP 2002 and it definitely did not like being put into reverse to stop the prop. It tended to jam and, while I could get it cleared by starting the engine in gear, this never felt good and I preferred to let it turn and put up with the noise.
Why the past tense? Well last winter I fitted a self-feathering Kiwiprop. The problem now no longer exists: while sailing the prop is silent and, even better, creates almost no drag: worth an extra knot in light winds, I reckon. I want to see it out of the water at the end of the season before singing its praises too highly, but so far so great!
Why the past tense? Well last winter I fitted a self-feathering Kiwiprop. The problem now no longer exists: while sailing the prop is silent and, even better, creates almost no drag: worth an extra knot in light winds, I reckon. I want to see it out of the water at the end of the season before singing its praises too highly, but so far so great!
26ft_bathtub
Well-Known Member
Presumably, with a standard prop, there is less drag when it's allowed to freewheel than if it's locked.
Vara
Well-Known Member
Don't even go their!!Leave it,it's not worth it.
dansar
Well-Known Member
npf1
Thanks for your reply.
Yes, your right. The previous owner of the yacht had a pulley fitted on the shaft which via a belt, powered an alternator. Unfortunately, the previous owner had died and therefore I couldn't ask if the system worked. I have no doubt that it did but on inspection during the buying period, found the alternator, because of its location, to be in a very sorry state due to the damp bilges--ie it didn't work anymore!!
David
Thanks for your reply.
Yes, your right. The previous owner of the yacht had a pulley fitted on the shaft which via a belt, powered an alternator. Unfortunately, the previous owner had died and therefore I couldn't ask if the system worked. I have no doubt that it did but on inspection during the buying period, found the alternator, because of its location, to be in a very sorry state due to the damp bilges--ie it didn't work anymore!!
David
andy_wilson
Well-Known Member
If you saw how slow the prop. turned under starter motor, you would realise that it is not putting any more noticable strain on the starter than trying to turn the engine with good compression.
Piers
Well-Known Member
Why do you want to fit a brake?