Go Back   RIBnet Forums > RIB talk > RIBs & ribbing
Click Here to Login

Reply
 
Thread Tools Search this Thread
 
Old 18 December 2016, 00:06   #1
Member
 
phoenixpete's Avatar
 
Country: UK - England
Length: 7m +
Join Date: Jul 2006
Posts: 214
Compton marine 8mt with twin 80hp yamahas.

Seen this rib for sale in Weymouth marina. What would be the expected top speed of this? I would have thought it needed more. It is for sale at the brokers in the marina. Looks in good condition.
__________________
phoenixpete is offline   Reply With Quote
Old 18 December 2016, 00:17   #2
RIBnet admin team
 
Poly's Avatar
 
Country: UK - Scotland
Boat name: imposter
Make: FunYak
Length: 3m +
Engine: Tohatsu 30HP
MMSI: 235089819
Join Date: Sep 2005
Posts: 11,632
Quote:
Originally Posted by phoenixpete View Post
Seen this rib for sale in Weymouth marina. What would be the expected top speed of this? I would have thought it needed more. It is for sale at the brokers in the marina. Looks in good condition.
If top speed matters to you I think there would be better ways of spending 20k.
__________________
Poly is offline   Reply With Quote
Old 18 December 2016, 09:48   #3
Member
 
phoenixpete's Avatar
 
Country: UK - England
Length: 7m +
Join Date: Jul 2006
Posts: 214
Quote:
Originally Posted by Poly View Post
If top speed matters to you I think there would be better ways of spending 20k.
You are probably right Just struggling to find something that ticks the boxes really. Have you got any suggestions? What i want is between 6.5 and 8mts plenty of deck space, so not completely covered in seats decent range and preferably big 4 stroke engine 150hp up.Will be used mainly for fishing and cruising usually no more than 2 or 3 people on board. 40 knots minimum would be nice.
__________________
phoenixpete is offline   Reply With Quote
Old 18 December 2016, 09:59   #4
Member
 
Fender's Avatar
 
Country: UK - England
Make: Zodiac
Length: under 3m
Engine: Scull
Join Date: Dec 2014
Posts: 531
Quote:
Originally Posted by phoenixpete View Post
Seen this rib for sale in Weymouth marina. What would be the expected top speed of this? I would have thought it needed more. It is for sale at the brokers in the marina. Looks in good condition.
Probably in the displacement range...............lol

Joking aside, twin 80's would be equivalent to a single 120-140hp ??
Not a lot for a 8m, most ribs of that size are 250 - 300hp.
__________________
Fender is offline   Reply With Quote
Old 18 December 2016, 10:04   #5
Member
 
phoenixpete's Avatar
 
Country: UK - England
Length: 7m +
Join Date: Jul 2006
Posts: 214
Quote:
Originally Posted by Fender View Post
Probably in the displacement range...............lol

Joking aside, twin 80's would be equivalent to a single 120-140hp ??
Not a lot for a 8m, most ribs of that size are 250 - 300hp.
Thats what i was thinking, just not enough power for that boat. A mate had an Atlantic 21 with Honda 225hp that was quick.
__________________
phoenixpete is offline   Reply With Quote
Old 18 December 2016, 14:39   #6
Member
 
Country: UK - England
Town: Dorset
Boat name: Viper
Make: XS
Length: 7m +
Engine: Outboard 2x 100
Join Date: Jul 2006
Posts: 221
My 7m with twin 90s tops out at 35knts.
__________________
oracle is offline   Reply With Quote
Old 18 December 2016, 18:43   #7
Member
 
Last Tango's Avatar
 
Country: UK - Scotland
Town: Denny
Boat name: Highland Bluewater
Length: 6m +
Join Date: Mar 2013
Posts: 1,647
Expecting 40knots is probably about right with 150hp on a 6.6mtr. Just be aware you're in the zone where you start throwing big power increases at it and gaining relatively little top end.
I can get 38kn on the 6.5mtr with 130hp. but far more important for me is being able to cruise at 25kn at around 3800RPM. I'm not going to spend much time flat out and the difference between being able to do 38 knots and 40 knots is kind of irrelevant.
The minimum requirement for planning is abount 50hp/ton so if you aim for twice that you shouldn't have any issues.
__________________
Last Tango is offline   Reply With Quote
Old 19 December 2016, 13:20   #8
Member
 
Country: UK - England
Town: Southampton
Boat name: SMH Rib / War Shot
Make: Ribtec / Scorpion
Length: 4m +
Engine: 100hp Yam/150hp opt
Join Date: Sep 2003
Posts: 2,069
RIBase
It might go reasonably well. It's a simple boat with not much weight in the way of fit out.
Have you asked the broker?

Looks reasonably tidy in the photos.
__________________
Searider is offline   Reply With Quote
Old 19 December 2016, 13:22   #9
Member
 
Country: UK - England
Town: Southampton
Boat name: SMH Rib / War Shot
Make: Ribtec / Scorpion
Length: 4m +
Engine: 100hp Yam/150hp opt
Join Date: Sep 2003
Posts: 2,069
RIBase
Quote:
Originally Posted by phoenixpete View Post
Thats what i was thinking, just not enough power for that boat. A mate had an Atlantic 21 with Honda 225hp that was quick.
I had use of an Atlantic 21 with twin 55hp Evinrudes. Did 33 knots.

My 6.5 Scorpion was originally rigged with a 90hp. Reportedly good for mid 30s.

Whilst "more" is "always" "better". Sometimes it isn't necessarily needed!
__________________
Searider is offline   Reply With Quote
Old 19 December 2016, 13:34   #10
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: 12,178
RIBase
Compton marine 8mt with twin 80hp yamahas.

At the risk of doing to death a subject that has already been done to death. Power isn't always about top speed, it's also about being able to get out of trouble, powering up the back of a wave in a following sea, getting through overfalls etc. People get hung up on top speed & the times when you can run flat out are few & far between, especially around our coasts. Give me low down grunt over top end any day[emoji106]
__________________
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 19 December 2016, 15:21   #11
Member
 
Maximus's Avatar
 
Country: UK - England
Town: Wild West
Boat name: No Boat
Make: No Boat
Length: under 3m
Join Date: Jan 2008
Posts: 5,306
Send a message via AIM to Maximus
Quote:
Originally Posted by Pikey Dave View Post
At the risk of doing to death a subject that has already been done to death. Power isn't always about top speed, it's also about being able to get out of trouble, powering up the back of a wave in a following sea, getting through overfalls etc. People get hung up on top speed & the times when you can run flat out are few & far between, especially around our coasts. Give me low down grunt over top end any day[emoji106]
Like wot Pikey said
I might add...It equates "Hole shot" which IMO In Poor/Rough conditions (especially biggish confused Seas) is paramount!
... Haveing said that with a well Ballanced,and correctly Propped Rig they needn't (in fact shouldn't) be mutually exclusive!...enabling you to fleet of foot from displacement speeds when conditions dictate ...AND command a decent Top end when you need/want it...to get somewhere quickly
__________________
A clever Man learns by his mistakes..
A Wise Man learns by other people's!

The Road to HELL ..is Paved with "Good inventions!"
Maximus is offline   Reply With Quote
Reply

Tags
yamaha


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 12:49.


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