Reply
 
Thread Tools Search this Thread
 
Old 19 July 2009, 06:35   #1
Member
 
Country: UK - England
Town: Leicestershire
Make: Avon SR4 Zodiac 310
Length: 4m +
Engine: Merc 40 2s Merc 15 2
Join Date: May 2009
Posts: 175
Prop advice needed alloy to stainless

Im changing my prop over to a stainless which is a 13p.
Having spoken to two companies in the week one say I need to stay the same pitch but having spoken to another they say I need to drop down to a 12p if going to a stainless.
I know that the props are different makes one being a Solas but does anyone know which is right ?
Ive had chopper props before and bought stainless props for other boats ive had in the past, when running the engine higher on the transom but for a normal application would I need to change pitch just swapping to a stainless ?
__________________

__________________
Jonny H is offline   Reply With Quote
Old 19 July 2009, 06:57   #2
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 235090687/235055163
Join Date: Jul 2005
Posts: 12,645
RIBase
I'd drop an inch.
__________________
Need spares,consoles,consumables,hire,training or even a new boat?

Please click HERE and HERE and support our Trade Members.

Join up as a Trade member or Supporter HERE
Nos4r2 is offline   Reply With Quote
Old 19 July 2009, 16:26   #3
Member
 
Country: UK - England
Town: Looe
Make: Delta
Length: 4m +
Engine: Mercury
Join Date: Apr 2004
Posts: 1,335
Im going to be different. Go up one pitch when going from Ally to Stainless.
Stainless props perform better than ally and cut through the water better. So you can go up one pitch.
__________________
Turbodiesel is offline   Reply With Quote
Old 19 July 2009, 21:24   #4
Member
 
Country: Other
Town: Stanley, Falkland Is
Boat name: Seawolf
Make: Osprey Vipermax 5.8
Length: 5m +
Engine: Etec 150
Join Date: Mar 2006
Posts: 3,688
Quote:
Originally Posted by Turbodiesel View Post
Im going to be different. Go up one pitch when going from Ally to Stainless.
Stainless props perform better than ally and cut through the water better. So you can go up one pitch.
That was the advice I got from Oakley Marine when I discussed props with them a couple of years ago, he said because the SS blades are stiffer and thus usually thinner on a stainless prop you can increase the pitch by an inch with no problems.

I didn't in the end, because I figured the risk of rotavating a rocky beach meant it was better to stick with a cheaper alli one so I just bent the prop not something more expensive.
__________________
A Boat is a hole in the water, surrounded by fibreglass, into which you throw money...

Sent from my Computer, using a keyboard and mouse
BogMonster is offline   Reply With Quote
Old 20 July 2009, 10:04   #5
Member
 
Country: UK - Wales
Town: swansea
Boat name: Too Blue
Make: BLANK
Length: 8m +
Engine: Suzuki DT225
Join Date: Mar 2004
Posts: 12,791
Quote:
Originally Posted by Turbodiesel View Post
Im going to be different. Go up one pitch when going from Ally to Stainless.
Stainless props perform better than ally and cut through the water better. So you can go up one pitch.
Do they though? I have stainless but is there REALLY that much difference???
__________________
codprawn is offline   Reply With Quote
Old 20 July 2009, 10:34   #6
Member
 
spartacus's Avatar
 
Country: UK - Scotland
Town: Aberdeenshire
Boat name: Sula
Make: Ribcraft 4.8m
Length: 4m +
Engine: Tohatsu 60hp + aux
MMSI: 235087213
Join Date: Jun 2007
Posts: 3,268
RIBase
Quote:
Do they though? I have stainless but is there REALLY that much difference???
As far as I'm aware this would make a difference on a large engine, however the difference would be negligible on smaller outboards, probably anything under 50hp. Nice bit of bling though.
__________________
spartacus is offline   Reply With Quote
Old 20 July 2009, 11:53   #7
Member
 
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
Stiffer blades, more weight. True, thinner blades, but also usually a more aggressive blade shape. Usually adds up to 100 to 200 rpm loss or so if diameter remains the same, from what I've seen.

If you could only try a single prop, I would say dropping an inch would be your best bet.

I would ask if you could try one and swap it out if it's wrong. If the supplier won't go for that, you might try different suppliers. Paying a bit more for that would be cheaper than getting stuck with the wrong prop.

jky
__________________

__________________
jyasaki 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





Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -5. The time now is 22:38.


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