seaesta2
New member
Dear all thanks to those who repsonded to my posting on the above. I did the posting on behalf of a mate who is currently sailing around Australia and recieving your respinse messages via radio!! The current situation is described on Ted's response below
"Halyard + Propeller
Dear Martin,
Thanks for that replies from Steve Cronin and Chris Stannard.
I read Steve's first:
Presumably Steve is talking about the constant velocity joint and plumber
block arrangement - I think Halyard Marine is N or Southhampton, Hants.
We had one of those on our previous boat.
We dont have room for one of these without moving the engine forward.
The shaft is very short.
His reply makes me think that the Nylon bush was fitted purposely to cure
the severe ringing, presumably originally encountered. So replacing the
prop will not fix it. We will have to put the Nylon bush back in.
With the Nylon we only had one ring at about 1300RPM.
On Chris reply - we went to the Yanmar Dealer who said the book says 16 by
10 for our boat with a boat speed of 7knots at 3600RPM. This is a 20HP
3GMD with a 2.6:1 reduction. The coupling is an R&D marine, (Baldock,
Herts) plastic coupling. The shaft is only very short about 3 ft. The
hull is an Alberg34 displacing design 14,000Ibs but obviously more like
7.5 ton as we have raised the waterline by about 6 inches for cruising.
With the plastic bush in and the remodelled prop we only had the one
narrow resonance.
Will try the sailing-milling test as soon as we get the opportunity.
Will see if we can get hold of the previous owner to confirm the reason
why the plastic bush was put in in the first place. It seems strange that
a propeller machined and marked for a 1.125inch shaft was fitted to the 1
inch shaft. The previous owner had the boat from new. The propeller was
marked 16by12 but the diameter measured 17inch.
Thanks again for your help.
Ted Popham.
"Halyard + Propeller
Dear Martin,
Thanks for that replies from Steve Cronin and Chris Stannard.
I read Steve's first:
Presumably Steve is talking about the constant velocity joint and plumber
block arrangement - I think Halyard Marine is N or Southhampton, Hants.
We had one of those on our previous boat.
We dont have room for one of these without moving the engine forward.
The shaft is very short.
His reply makes me think that the Nylon bush was fitted purposely to cure
the severe ringing, presumably originally encountered. So replacing the
prop will not fix it. We will have to put the Nylon bush back in.
With the Nylon we only had one ring at about 1300RPM.
On Chris reply - we went to the Yanmar Dealer who said the book says 16 by
10 for our boat with a boat speed of 7knots at 3600RPM. This is a 20HP
3GMD with a 2.6:1 reduction. The coupling is an R&D marine, (Baldock,
Herts) plastic coupling. The shaft is only very short about 3 ft. The
hull is an Alberg34 displacing design 14,000Ibs but obviously more like
7.5 ton as we have raised the waterline by about 6 inches for cruising.
With the plastic bush in and the remodelled prop we only had the one
narrow resonance.
Will try the sailing-milling test as soon as we get the opportunity.
Will see if we can get hold of the previous owner to confirm the reason
why the plastic bush was put in in the first place. It seems strange that
a propeller machined and marked for a 1.125inch shaft was fitted to the 1
inch shaft. The previous owner had the boat from new. The propeller was
marked 16by12 but the diameter measured 17inch.
Thanks again for your help.
Ted Popham.