3 blade props, can Yanmar sail drives handle it?

[Lew M]

I have 2 blade (fixed) props on the 46' Hughes cat we just bought. I'm inclined to switch to 3 blade, but hesitate over concern for the old Yanmar SD 20 saildrives' ability to withstand the additional torque, and general loading over the long haul. Does anyone have experience with this choice. Thanks.

[UNCIVILIZED]

Welcome to CF!

On your question. My thinking is that if you can't switch to such propellers, then a whole bunch of folks all screwed up severely in signing off on your propulsion units. As they need to be able to handle a lot more thrust then you'll ever be able to apply via prop changes.
That said, they're the ones that you need to ask, given that they built them.

Have you considered going to feathering props at all? That way you get to have excellent handling characteristics under power, & retain having little drag from your props when under sail. Those qualities & more have kept me as being a Maxprop fan or several decades.


PS: Which of Kurt's designs? I'm a bit jealous as he draws some nice boats.

[GordMay]

Greetings and welcome aboard the CF, Lew.

See ➥ http://portal.mastry.com/bulletins/S...0Selection.pdf

[DotDun]

Originally Posted by Lew M

I have 2 blade (fixed) props on the 46' Hughes cat we just bought. I'm inclined to switch to 3 blade, but hesitate over concern for the old Yanmar SD 20 saildrives' ability to withstand the additional torque, and general loading over the long haul. Does anyone have experience with this choice. Thanks.

Any specific reason for wanting 3 blade props?

[Sailorman Ed]

I have 3 blades on my SD20 but seems a bit of a load on my 2GM20 engines. They do seems to cause more drag when under sail.
If you decide to replace yours, I would be interested in buying your old 2 blade props.
Ed