Thread Tools Search this Thread
Old 23 September 2015, 14:58   #11
RIBnet supporter
Erin's Avatar
Country: UK - Channel Islands
Town: A large rock
Boat name: La Frette
Make: Osprey Vipermax
Length: 6m +
Engine: 200 Suzzy
Join Date: May 2004
Posts: 2,797
From my fairly restricted experience of shaft drive semi-displacement boats I think shaft speed tends to be around 1750rpm for best efficiency. I guess after that you start to induce too much prop slip and lose thrust. I wonder whether a smaller diameter 4 blade might help. It could be mounted a tad lower which would also keep it further from the surface and reduce ventilation. There is a rule of thumb somewhere about distance between top of prop and underside of hull. I'll let you know if I find it.
Erin is offline   Reply With Quote
Old 23 September 2015, 16:18   #12
Country: UK - England
Town: Southampton
Make: Ballistic
Length: 7m +
Engine: Yam 225
Join Date: Jun 2010
Posts: 887
Go the clarkson route and fit a oversized OB

Starovich is offline   Reply With Quote
Old 23 September 2015, 16:29   #13
RIBnet admin team
willk's Avatar
Country: Ireland
Make: Redbay Boats
Length: 9m +
Engine: 370hp
Join Date: Feb 2008
Posts: 12,154
All grist for the mill, guys - keep it coming!

willk is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 18:36.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.