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Old 07 December 2005, 12:14   #1
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Too much power?

I'm buying a Humber 5.5m Ocean Pro and I'm waivering over which engine I should get. My previous boat was a 5.4m Tornado with a Yamaha 90 2-stroke. She had alot of difficulty getting on the plane with 6 divers and a coxswain so I'm keen to avoid a similar problem this time. Just to make things interesting, I'm also fairly tightly constrained by weight because I'll be towing with a normal family car, so the lighter the better and 4-strokes are right-out. At the moment I've pretty much made up my mind on a 115HP Evinrude E-tec, which is 50Kg heavier than the Yamaha 90 but I think necessary none the less. Does anyone have a similar boat, what engine did you go for? Is the 115HP overkill? Or does anyone have any recommendations either way?
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Old 07 December 2005, 12:22   #2
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What about Mercury / Mariner 115 Optimax, weight about 170 kgs

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Old 07 December 2005, 12:25   #3
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ask the dealer if they can supply a 2005 engine for you at a discounted price, ie for merc or mariner that is....

if the boat is rated for 115 then you have no problems, always better to go bigger than smaller if the car towing situation will allow

if the boat can take a bigger engine and the bigger engine is the same weight as the 115 then go bigger

Quote:
Originally Posted by Will F
I'm buying a Humber 5.5m Ocean Pro and I'm waivering over which engine I should get. My previous boat was a 5.4m Tornado with a Yamaha 90 2-stroke. She had alot of difficulty getting on the plane with 6 divers and a coxswain so I'm keen to avoid a similar problem this time. Just to make things interesting, I'm also fairly tightly constrained by weight because I'll be towing with a normal family car, so the lighter the better and 4-strokes are right-out. At the moment I've pretty much made up my mind on a 115HP Evinrude E-tec, which is 50Kg heavier than the Yamaha 90 but I think necessary none the less. Does anyone have a similar boat, what engine did you go for? Is the 115HP overkill? Or does anyone have any recommendations either way?
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Old 07 December 2005, 13:46   #4
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If I were you, I'd find what the hull is rated for, and make your decision on which motor based on that.

As a fellow diver, I am well aware of the amount of weight a boat loaded with gear and divers (and, on the trip back, water) has to deal with; go max power and you won't have to second-guess your purchase.

Given that you will be adding a ton (literally) of weight in the passenger area, a few more pounds in back is not going to matter all that much, I think.

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Old 07 December 2005, 17:56   #5
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Some folk on ribnet rate the Suzi 140. That would give you the extra oomph for carrying your gear.
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Old 07 December 2005, 18:14   #6
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Quote:
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Some folk on ribnet rate the Suzi 140. That would give you the extra oomph for carrying your gear.
I have one - on my ribcraft 5.85 - love it.

You also have to remember its lighter than ther suzuki 90hp
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Old 08 December 2005, 05:12   #7
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For getting the rib on the plane loaded with divers, its the torque / pickup you want rather than raw power at the top end. You defnintely want a 2 stroke for pushing load around at that size.

The prop you pick for carrying load is important as well - worth discussing with the dealer when you buy the boat.

Our club dive rib (6m) has an Optimax 115, which pushes 6 divers + a cox up on the plane without too much bother, and it is a good engine too.

Ricky
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Old 08 December 2005, 14:38   #8
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You can also change the prop to one that lets you get to a plane faster. That might save you a lot of money.
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Old 08 December 2005, 16:07   #9
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and try doel fins on the prop, they work wonders in certain situations
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Old 08 December 2005, 16:36   #10
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Quote:
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and try doel fins on the prop, they work wonders in certain situations
Can't imagine what situation that would be, might be worth trying them on the cav plate though!
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