Reply
 
Thread Tools Search this Thread
 
Old 16 January 2007, 07:26   #1
Member
 
Country: UK - England
Town: Bursledon
Boat name: Mustard
Make: Ribeye 785
Length: 7m +
Engine: Yamaha 200/Merc 6
MMSI: 235068693
Join Date: Oct 2006
Posts: 618
Prop Size, 90hp Mercury 4stroke on 5.85 Ribcraft

Hi,

Can anyone give me some advice on which would be the best prop size for a Mercury 90hp four stroke on a Ribcraft 585? I want to buy a new prop and keep the old one as a spare and can't read the size.

Is it worth the extra for a stainless prop, given that I do use the boat in difficult harbours in Norfolk, hence the risk of grounding.

Thanks!
__________________

__________________
JABS is offline   Reply With Quote
Old 16 January 2007, 08:23   #2
Member
 
Country: UK - Scotland
Town: Uphall
Boat name: Iona
Make: Zodiac
Length: 5m +
Engine: Optimax 115
MMSI: 235053483
Join Date: Sep 2006
Posts: 105
Prop

Hi this might be useful: mercury prop selector
http://appcenter.mercurymarine.com/propSelector/

They seem to suggest 25 or 26 pitch
__________________

__________________
three-rex is offline   Reply With Quote
Old 16 January 2007, 09:17   #3
Member
 
Country: UK - Wales
Town: Pwllheli-North Wales
Boat name: Delta 1
Make: Delta
Length: 6m +
Engine: Mariner 90hp Optimax
Join Date: Mar 2001
Posts: 2,367
Quote:
Originally Posted by three-rex View Post

They seem to suggest 25 or 26 pitch
I bet it would only get 2500rpm with a 25 or 26, should be revving to 5500 - 6000

I would guess a 17 pitch ally or 18 pitch stainless, best to confirm with Jason @ Ribcraft or hve a look at Jools site www.ribpanther.co.uk (ribcraft with 90hp merc 4 stroke)

Drop Ian a line on 07947807349 and he will get you a new prop cheeper than anyone else, hes got loads of props for merc/mariner in stock.

Jono
__________________
JG Marine Services Ltd Specialist Safety Boat Services

Bodfuan Shoot Ltd Traditional British Game Shooting
Jono Garton is offline   Reply With Quote
Old 16 January 2007, 09:21   #4
Member
 
Pete7's Avatar
 
Country: UK - England
Town: Gosport
Boat name: April Lass
Make: Moody 31
Length: 9m +
Join Date: Aug 2001
Posts: 4,850
Quote:
Originally Posted by three-rex View Post
They seem to suggest 25 or 26 pitch
I would have thought 17" or 19" near the mark. Size is stamped on the end of the prop with the part number, but if you can't read it send it to Steel Developments and ask them to measure it. They should be competitive in quoting a replacement prop too.

Pete
__________________
.
Ribnet is best viewed on a computer of some sort
Pete7 is offline   Reply With Quote
Old 16 January 2007, 09:31   #5
Member
 
Country: UK - Scotland
Town: Uphall
Boat name: Iona
Make: Zodiac
Length: 5m +
Engine: Optimax 115
MMSI: 235053483
Join Date: Sep 2006
Posts: 105
Quote:
Originally Posted by Jono Garton View Post
I would guess a 17 pitch ally or 18 pitch stainless,
Jono
Is what I thought - I was just saying what the calculator said - must have been using a different gear box on the calculator model

Odd - I just done it again and it suggests 19 - 20 - just as I suspected - I'm shite!!!!
__________________
three-rex is offline   Reply With Quote
Old 16 January 2007, 10:56   #6
Member
 
Nick Hearne's Avatar
 
Country: UK - England
Town: Bucks
Boat name: Blue & Ding Dong
Make: Ribeye,SR4 & Bombard
Length: 6m +
Engine: 115,50 & 15Hp Yams
Join Date: Feb 2004
Posts: 3,242
My old 5.75 Viper with a 100hp 2st ran with a 19 when lightly loaded & a 15 when up to 8 divers & kit!
__________________
Nick Hearne is offline   Reply With Quote
Old 19 January 2007, 10:16   #7
Member
 
Country: UK - England
Town: Bursledon
Boat name: Mustard
Make: Ribeye 785
Length: 7m +
Engine: Yamaha 200/Merc 6
MMSI: 235068693
Join Date: Oct 2006
Posts: 618
Thank you!

Looks as if I need to go for an 18!

Anyone tell me whether to go for stainless or ally?

Thank you!
__________________
JABS is offline   Reply With Quote
Old 19 January 2007, 14:28   #8
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 JABS View Post
Looks as if I need to go for an 18!

Anyone tell me whether to go for stainless or ally?

Thank you!
when I looked into this the best answer seemed to be stainless for best performance if you don't expect to hit anything, alli if you are operating/launching in conditions where you might whack the prop on the bottom because if you do this with an alli prop it will break the prop, if you do it with a stainless it will (might) break the gearbox instead

so as I launch off a rocky beach I bought an alli, and I have belted it on the bottom already so glad I chose what I did
__________________
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 19 January 2007, 15:03   #9
Member
 
Country: USA
Length: 5m +
Join Date: Jan 2007
Posts: 20
Quote:
Originally Posted by JABS View Post
Looks as if I need to go for an 18!

Anyone tell me whether to go for stainless or ally?

Thank you!
I'd agree with Stephen... stainless is great for top end performance, but if you're going to in and around the rocky shore - definitely stay with aluminum. Better to have a sacrificial prop than a sacrificial lower unit. Take a look at the Ribcraft USA RIB Blog. They've been talking about props lately. www.ribcraftusa.com/blog
__________________

__________________
Cabs 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 08:22.


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