Pearson 365 propeller

[dansail]

My Pearson 365 is fitted with a Westerbeke W40 and the propeller is a 17x10 LH three bladed prop. The engine revs freely up to max RPM at 3000 with a speed of 6.5 kts. When motoring into a chop with a stiff headwind my speed drops to about 3 kts. I have checked that the paragon gearbox is not slipping. I'm considering changing the prop for a 17x12 for more thrust.
I want to get a new prop prior to hauling out. The propshaft is 1 1/8th diameter.
Does anyone have the standard propeller dimensions?
I need the diameter of the shaft hole at both ends, the length of the hub, taper (ie, is it 1-12 or 1-10 taper). and finally the width of the keyway.

[pistarckle]

Also look into a four blade .

[barnakiel]

There used to be a detailed props spreadsheet at Vetus. G oogle some.

b.

[barnakiel]

PS tree blade props come in various circle % areas, check out this may help too.

b.

[pistarckle]

Getting the correct prop the first or second time is tough . I worked in a boatyard and try ed a bunch and was never zactually satisfied . Ya know ya can also have your prop re-pitched for less than half . It is possible to change your prop underwater till ya get it right ! Some of us old guys have changed shafts while in the water !
Ya got a nice boat !

[Cheechako]

You are going the wrong way on the pitch. If you are at cruising RPM going into a chop, but only making half hull speed, the prop is cavitating. Going to a 12 pitch will make it worse. assuming you are pitched to get to the right rpm in flat water.... all you can do is get the right pitch for your rpm. After that you need to look at various prop design... Max Props are great.