Go Back   RIBnet Forums > RIB talk > Engines & props
Click Here to Login

Reply
 
Thread Tools Search this Thread
 
Old 10 April 2008, 21:02   #1
Member
 
Country: UK - England
Town: South Coast
Boat name: No Name
Make: Ribx-450
Length: 4m +
Engine: Outboard 60hp 2 Merc
Join Date: Apr 2008
Posts: 108
4.50 Metre Rib-x 60hp Mercury What prop?

Can anyone recomend a prop for my outfit?

Often runnig with two to three adults in it.

I have a 4.5 meter centre console rib, it has a 2 stroke 3 cylinder mercury outboard with currently a 14 pitch prop.

It seem to rev too high to 6500 rpm???........... Mercury quote 5500 rpm max.

Current prop is 73138A4OP14 (14 Pitch)


Does anyone have a recomendation for a prop?

Does anyone have a spare prop for sale?

Many thanks

Chris
__________________
rib-x450 is offline   Reply With Quote
Old 10 April 2008, 21:11   #2
Member
 
ashbypower's Avatar
 
Country: UK - England
Town: Salisbury
Boat name: Blue C
Make: XS 600
Length: 6m +
Engine: 125hp Opti
MMSI: 235082826/235909566
Join Date: Jan 2004
Posts: 1,439
As a general rule of thumb a 2" change in pitch will have a 200 RPM change. i.e up in pitch down in RPM.
Hope thatb helps

By the way Welcome to the Forum
__________________
Brian C
APS Marine Centre
ashbypower is offline   Reply With Quote
Old 10 April 2008, 23:22   #3
RIBnet admin team
 
Nos4r2's Avatar
 
Country: UK - England
Town: The wilds of Wiltshire
Boat name: Dominator
Make: SR5.4
Length: 7m +
Engine: Yam 85
MMSI: 235055163
Join Date: Jul 2005
Posts: 13,068
RIBase
Odd question but are you sure your revcounter is reading right?
__________________
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 12 April 2008, 17:58   #4
Member
 
Country: UK - Scotland
Town: Port Logan
Boat name: Red Fox
Make: Zodiac Pro 500
Length: 4m +
Engine: Yamaha 70hp
MMSI: 232004329
Join Date: Aug 2002
Posts: 323
http://sites.mercurymarine.com/porta..._schema=PORTAL
__________________
Red Fox is offline   Reply With Quote
Old 12 April 2008, 22:48   #5
Member
 
Country: Netherlands
Town: Holland
Make: Brig F360S
Length: 3m +
Engine: Yamaha 70hp
Join Date: Jan 2008
Posts: 85
Quote:
Originally Posted by ashbypower View Post
As a general rule of thumb a 2" change in pitch will have a 200 RPM change. i.e up in pitch down in RPM.
Hope thatb helps

By the way Welcome to the Forum
To be honest, I don't think that's correct, the rule of thumb: 1" higher pitch = 200 RPM less. So 2" pitch higher will result in a loss of 400 RPM. I think it's reasonable to test a 19" pitch prop on the 60hp merc.
__________________
reinier is offline   Reply With Quote
Old 14 April 2008, 19:52   #6
Member
 
Country: UK - England
Town: South Coast
Boat name: No Name
Make: Ribx-450
Length: 4m +
Engine: Outboard 60hp 2 Merc
Join Date: Apr 2008
Posts: 108
19 pitch prop?

Thansk for the advice everyone...........

The highest pitch mercury make for my engine is a 19 pitch, if we base 1 pitch on 200 rpm will it be enought to bring the revs down to a safe limit? 1000 rpm to high ?

Has anyone else got a 4.5 meter with a 60hp on it?

Many thanks for the advice........


Quote:
Originally Posted by reinier View Post
To be honest, I don't think that's correct, the rule of thumb: 1" higher pitch = 200 RPM less. So 2" pitch higher will result in a loss of 400 RPM. I think it's reasonable to test a 19" pitch prop on the 60hp merc.
__________________
rib-x450 is offline   Reply With Quote
Old 14 April 2008, 22:43   #7
Member
 
Country: Netherlands
Town: Holland
Make: Brig F360S
Length: 3m +
Engine: Yamaha 70hp
Join Date: Jan 2008
Posts: 85
Yeah, from 14" to 19" pitch = 5" pitch increase, mutiplied by 200rpm = 1000rpm decrease... If you use a stainless steel prop your rpm's will fall another 100 or maybe 200rpm. If you use a fourblade prop it will decrease the rpm's also with 100 or 200rpm.

If the 6500rpm is with a 14" aluminium prop, I suggest testing a 3 blade S/S 19" pitch prop.
__________________
reinier is offline   Reply With Quote
Old 15 April 2008, 17:28   #8
Member
 
Country: UK - Scotland
Town: Port Logan
Boat name: Red Fox
Make: Zodiac Pro 500
Length: 4m +
Engine: Yamaha 70hp
MMSI: 232004329
Join Date: Aug 2002
Posts: 323
Your prop number 73138A40P14 is the standard Black Max prop that is put on a 60hp Mercury so are you sure the rev counter is accurate. Get a dealer to rig your engine to his laptop with the diagnostic program running and he will be able to tell you the exact revs the engine has been doing.
__________________
Red Fox is offline   Reply With Quote
Old 16 April 2008, 19:55   #9
Member
 
Country: UK - England
Town: South Coast
Boat name: No Name
Make: Ribx-450
Length: 4m +
Engine: Outboard 60hp 2 Merc
Join Date: Apr 2008
Posts: 108
Rev counter problem

Thanks for your advice, I took out the rev counter today and found it to be sqithed in the wrong position, eg for the wrong number of cylinders........ Havent been able to retest it yet. Then will need to check the prop again. A rule to never trust somelse to do things right.........The guy I bought it from installed the rev counter!!!

Will it be reading double?

Quote:
Originally Posted by Red Fox View Post
Your prop number 73138A40P14 is the standard Black Max prop that is put on a 60hp Mercury so are you sure the rev counter is accurate. Get a dealer to rig your engine to his laptop with the diagnostic program running and he will be able to tell you the exact revs the engine has been doing.
__________________
rib-x450 is offline   Reply With Quote
Old 17 April 2008, 20:44   #10
Member
 
Country: UK - England
Town: bedford
Make: tornado
Length: 5m +
Engine: outboard 60hp merc
Join Date: Oct 2007
Posts: 338
Prop selection

I have a Tornado 5mtr with a 60hp 2 str that I run with a 13p and a 14p Alu Merc prop on. Usually I run with the 13p as I take up to 4 divers on it. However when I am running with the family and just pottering about I use the 14p, I would have thought that the 14p is probably about right for general use and then perhaps a 15p for light use. I use Alu as I have heard the odd horror story about SS props damaging the gear box if you hit the bottom.
__________________
davej is offline   Reply With Quote
Old 20 February 2022, 18:08   #11
Member
 
Country: Ireland
Town: Dunmore East
Make: Selva
Length: 4m +
Engine: 1987 Mercury 60hp 2t
Join Date: Feb 2022
Posts: 3
Resurrecting this Thread!

Hi all, hoping I get a response as I have the same 4.5m rib and Merc 60hp combo. Just hoping that I can find out what results the owner had after the fact. I haven't had my boat on the water yet but I'm sure the 14 inch pitch will be too shallow. The boat is very light and I believe the 60hp is actually closer to 70hp by today's standards. Was thinking about finding a 19in pitch prop somewhere but I'd like to be sure before buying a hard to find prop!!

Thanks!!
__________________
jakemarsden is offline   Reply With Quote
Old 20 February 2022, 19:01   #12
Member
 
Pikey Dave's Avatar
 
Country: UK - England
Town: South Yorks
Boat name: Black Pig
Make: Ribcraft
Length: 5m +
Engine: DF140a
MMSI: 235111389
Join Date: Feb 2008
Posts: 12,149
RIBase
Quote:
Originally Posted by jakemarsden View Post
Hi all, hoping I get a response as I have the same 4.5m rib and Merc 60hp combo. Just hoping that I can find out what results the owner had after the fact. I haven't had my boat on the water yet but I'm sure the 14 inch pitch will be too shallow. The boat is very light and I believe the 60hp is actually closer to 70hp by today's standards. Was thinking about finding a 19in pitch prop somewhere but I'd like to be sure before buying a hard to find prop!!



Thanks!!


Until you’ve had it on the water & got some WOT figures, it’s all hypothetical & pretty pointless tbh.
__________________
Rule#2: Never argue with an idiot. He'll drag you down to his level & then beat you with experience.
Rule#3: Tha' can't educate pork.
Rule#4:Don't feed the troll
Pikey Dave is offline   Reply With Quote
Old 20 February 2022, 19:05   #13
Member
 
Country: Ireland
Town: Dunmore East
Make: Selva
Length: 4m +
Engine: 1987 Mercury 60hp 2t
Join Date: Feb 2022
Posts: 3
Quote:
Originally Posted by Pikey Dave View Post
Until you’ve had it on the water & got some WOT figures, it’s all hypothetical & pretty pointless tbh.
Yes of course! Just wondering what other people's experiences have been for the time being. I imagine it'll be quite a fast rib, secretly hpoing for 40kts
__________________
jakemarsden is offline   Reply With Quote
Old 20 February 2022, 21:47   #14
Member
 
Country: UK - England
Town: Nottinghamshire
Make: Ranieri 15
Length: 4m +
Engine: Suzuki DF50
Join Date: Jul 2016
Posts: 1,280
By coincidence this was recently discussed.
2005 Mariner 60hp 2 stroke
__________________
Limecc is offline   Reply With Quote
Reply


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




All times are GMT. The time now is 16:40.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.