New Prop

[slimted]

My prop has suffered from galvanic corosion and has to be replaced. It seems like you need to be an NASA trained engineer before you can even think of attempting the calcs for new one.
Not sure of how to procede so as to minimise risk of making wrong choice.
Boat is Cobra 750 with fin. Engine is new Yanmar 2YM15. I have been told that the original prop was machined down to fit so may never have been best spec anyway.
Just did a quick search of forum apologies if this is old ground.

 

[sheeplove]

Talk to Bruntons props. (Google them)

 

[cindersailor]

Castle Marine have a calculator you can download. It assumes a 3-bladed prop with 55% disc area ratio (DAR). Go to http://www.castlemarine.co.uk/pitch.htm

 

[TiggerToo]

Try these guys Kiwiprop . I am VERY satisfied with mine

 

[bendyone]

asumming a 2:1 gearbox should be around a 14 x 9 - 3 blade prop

 

[Clyde_Wanderer]

I just recieved my new prop last week from Lancing marine, who were able to tell me what pitch I required from boat dislpacement, engine working revs, output ratio, engine hp, hull and keel type, loa, and lwl, I already knew the max dia,
they will need to know shaft taper, if you dont know this, measure the largest diameter of the taper and the smallest dia of taper, and the axial length between them, also the size of key-way cut out.
My 13x8 round three blader cost £218 inc vat and cariage and was delivered withen the specified time hastle free.

 

[srp]

Another vote for Lancing Marine - the bloke I spoke to was really helpful and knowledgeable, and took the trouble to explain why he recommended the particular prop. There are quite a few different prop calculators on the web - try a Google search. It's interesting to try a few and see if they come up with the same answers. You'll then have a starting point when you talk to your chosen supplier.