Reply
 
Thread Tools Search this Thread
 
Old 05 October 2016, 11:20   #1
Member
 
Country: UK - England
Town: redcar
Boat name: glade
Make: quicksilver
Length: 4m +
Engine: outboard
Join Date: Jun 2011
Posts: 15
engine size prop pitch

hi all
just taken delivery of a lovely new boat
its a ribcraft 4.8 with a 60 hp engine
with 4 people on its lovely top end speed of 38 knots and gets on the plane real easy

however i do want to use it for diving and will be loading it with 4 people and 4 sets of diving gear aprox 500kg

when i loaded it with the gear it was slow to get on the plane perhaps 40 seconds

so down to specifics it currently has a 17 pitch propeller on and ribcraft are suggesting i may be better off with a 16 pitch which will reduce top end speed but speed up plane time

have you been through this can you advise how much it will drop top end speed and how will it effect the boat

any advice gladly received
__________________

__________________
d1ve1n is offline   Reply With Quote
Old 05 October 2016, 17:32   #2
Member
 
Country: Australia
Town: Dalmeny
Make: zodiac
Length: 5m +
Engine: outboard
Join Date: May 2015
Posts: 443
That's great performance you are getting, don't think you can get a 16pitch as they normally drop by two, so a 15 would be the next drop down. Is your prop aluminium or stainless and what 60hp engine is on the boat. I get 29 knots max from a 70hp on a 5.2 rib after much prop testing and fine tuning, is your speed from a gps or dash mount gauge?

What maximum rpm do you get.

Jon
__________________

__________________
jonp is offline   Reply With Quote
Old 06 October 2016, 01:44   #3
Member
 
Roflhat's Avatar
 
Country: UK - Scotland
Town: Isle of Lewis
Make: Thundercat (TI)
Length: 4m +
Engine: Yamaha 70
Join Date: Jul 2010
Posts: 545
RIBase
That's decent speed you're getting, I would be dropping more than 1" of pitch if you're carrying that amount of gear. 14/15" pitch props is what I'd be looking for.
__________________
Roflhat is offline   Reply With Quote
Old 06 October 2016, 06:03   #4
Member
 
Country: UK - England
Town: redcar
Boat name: glade
Make: quicksilver
Length: 4m +
Engine: outboard
Join Date: Jun 2011
Posts: 15
Quote:
Originally Posted by jonp View Post
That's great performance you are getting, don't think you can get a 16pitch as they normally drop by two, so a 15 would be the next drop down. Is your prop aluminium or stainless and what 60hp engine is on the boat. I get 29 knots max from a 70hp on a 5.2 rib after much prop testing and fine tuning, is your speed from a gps or dash mount gauge?

What maximum rpm do you get.

Jon
hi
speed is from gps
its an aluminium prop
the engine is a susuki 4 stroke
conditions were like glass
__________________
d1ve1n is offline   Reply With Quote
Old 06 October 2016, 07:54   #5
Member
 
Country: UK - Scotland
Town: Denny
Boat name: Hebridean Storm
Make: Coastline
Length: 6m +
Engine: Honda 130hp
MMSI: 235107505
Join Date: Mar 2013
Posts: 577
If you can get it I'd go for a 16" vented stainless something like a Laser II.
(Don't know if there's an equivalent for Suzuki)

That'll resolve the issue with the engine revs when loaded down without compromising the top end.
__________________
Last Tango is offline   Reply With Quote
Reply

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- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 09:08.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.