- This topic has 6 replies, 3 voices, and was last updated 1 day, 19 hours ago by
.
-
Posts
-
Macwester 27 with Beta BD722 / Beta 20, rated 20 hp at 3600 rpm. Looking for real-world propeller matches. What gearbox model and ratio are you running, shaft diameter, prop diameter/pitch/blade count, and what max rpm do you achieve under load with a clean hull? I need to source a new prop for our new Mac 27 but suspect the current 2 blade is not right.
Hi Mate, my Stag 28 with the bd722 was sized for 13″x 9″ p , however a 12″ x 10″ pitch should be equally as efficient if you need a bigger clearance, it must be a Right hand prop preferably with a 25mm dia shaft as opposed to the old 1″ dia shaft
Regards Stuart Marklew.
Hi Colin. I have a MW 27 (1976 : not that that matters, for all years of production, the hull and keels were not changed). I also have the Beta 20, with 2:1 reduction gearbox.
Unfortunately, I can’t find where I noted the inscriptions on the prop, and as the boat is afloat for the season, I can’t go and have a look. From memory, it’s 15” diameter, and 12” pitch, 3 blades, R.H. rotation.
That seems to be very well matched, I can reach around 6 knots in calm water at 2800rpm, without any fuss. More throttle will increase the size of the bow wave, and perhaps add half a knot, but no black smoke from the exhaust like my previous MW27 would do with its Volvo Penta MD2B 25 hp!
You must be logged in to view attachments.
Sorry, I forgot some of your questions: It’s a 1” shaft, and a PRM150 gearbox. The entire drive train, prop and prop shaft, etc. was replaced in 2014 by a previous owner in 2014/5, when the new engine was fitted. Personally, I would have preferred a classic stern gland with a stuffing box , but there is a dripless “Volvo” style one fitted.
You must be logged in to view attachments.
- You must be logged in to reply to this topic.