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Old 17 December 2016, 23:06   #1
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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.
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Old 17 December 2016, 23:17   #2
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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.
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Old 18 December 2016, 08:48   #3
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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.
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Old 18 December 2016, 08:59   #4
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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.
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Old 18 December 2016, 09:04   #5
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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.
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Old 18 December 2016, 13:39   #6
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My 7m with twin 90s tops out at 35knts.
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Old 18 December 2016, 17:43   #7
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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.
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Old 19 December 2016, 12:20   #8
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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.
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Old 19 December 2016, 12:22   #9
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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!
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Old 19 December 2016, 12:34   #10
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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]
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Old 19 December 2016, 14:21   #11
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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
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