The Correct Prop For my Engine?

[rodd234]

Can anyone tell me a good site to get the correct Prop for my Volvo-Penta Md7a ...........
I have a 3/4 inch shaft with a left handed prop with 2 blades which when in use is about as useful as a chocolate fireguard!!!
I have been on one site that needed a Degree in Astro-physics and Mathamatics to work out!!!
Please help this Devon lad who is Strong in the Arm but Thick in the HEAD!!!!!!!!!!!

Many Thanks Richard

 

[DipperToo]

I used a small xls calculator for my last boat which was 'freeware'. The site no longer exists but I could email it to you if you like?

 

[bills4us]

It may be of some help to phone Castle Marine 01286 674322 .They have a good site which calculates prop dia/pitch for power boats, but it does not include M/Y, they supply props so should be able to help.

 

[sailorman]

http://www.castlemarine.co.uk/

 

[ebbtide]

Forget the formulae, for best results you need an overlay of expertise too. Couldn't fault Andrew Childs of Clements Engineering tel 01234 378814 who found a 'mistake' inherent in the design after 20 years. Prompt and knowledgeable service - but it cost me a new prop!