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

Reply
 
Thread Tools Search this Thread
 
Old 11 June 2011, 13:53   #1
ADS
Member
 
Country: UK - England
Town: Dorset
Length: 4m +
Join Date: Oct 2003
Posts: 1,410
Ribcraft 4.8/ 60HP Mariner Prop Choice

Afternoon guys, I have recently bought a Ribcraft 4.8 with a 60hp 2 stroke Mariner. The prop is in fairly poor condition and needs to be replaced.
It does however over rev, I can get the rev counter round to 7000 and it sounds like its revving its bollocks off, not idea of speed as its lacking instrumentation but it feels about 30 knots at WOT.
Current Prop is a 14" ally, whats everyone else running I am considering going to a 15".
I want a compromise really of reasonable cruising speed and a decent holeshot, Im not after one or the other just a balance of both.

Any help much appreciated.

Thanks,
__________________
ADS is offline   Reply With Quote
Old 14 June 2011, 17:04   #2
Member
 
Country: UK - England
Town: bicester
Length: no boat
Engine: outboard only
Join Date: Feb 2009
Posts: 913
Alex if i were you i would phone jason at ribcraft and ask what props were fitted on that combination at the factory when new, you can cause damage by over reving as well as not getting to the factory wide open throttle when running flat out, (note all figers are in gear and on the water NOT reving in nuetral)
__________________
uncle al is offline   Reply With Quote
Old 14 June 2011, 19:19   #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: 13,069
RIBase
Ads, how bad exactly is the prop that's on there? As in,could it be badly enough damaged to slip to 7k rpm?
__________________
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 15 June 2011, 20:43   #4
ADS
Member
 
Country: UK - England
Town: Dorset
Length: 4m +
Join Date: Oct 2003
Posts: 1,410
Original prop is fairly shot.

I rang up Ribcraft and they recommended going to a 15. This is a fairly light boat remember, 60HP 2 stroke, single console, on deck tank and no a frame, it is however antifouled.

I bought a brand new 15" prop from the local dealer yesterday and went out, one up with very little fuel and trimmed out it revs to 6000rpm at WOT and a max speed of 33 knots over two runs (GPS).

I also went out 3 up with 30 litres of fuel a wakeboard and loads of other tat,
it maxed out at 28 knots but still pulled 5800RPM.

Cruising at 25 knots was at 5200 rpmish so abit high for my liking still.
Maybe its because I am not used to having a rev counter and ignorance is bliss?
Perhaps it wants a 16"? Peak power on this outboard is between 5 and 6000 depending on where you read.
It didn't exactly feel urgent when 3 up either, kind of like the last 2000rpm were just revs.
After my SR4/ 50HP this boat is abit of a dissappointment, the SR4 you really had to 'drive' and if you got it wrong it would try and kill you, I reckon you could make a cheese sandwich while reading the newspaper on this one at WOT!
__________________
ADS 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 05:16.


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