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Old 22 October 2007, 14:51   #1
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Country: UK - England
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Boat name: Max Power
Make: Cobra 7.5
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What Speed Should I Expect From This Setup?

Advice please,

What speed should I expect from this.....................

7.5M Cobra with 225hp Mercury Optimax with stainless 21 pitch prop.

1 person, 25 Gallons of fuel.

Been out today in flat conditions & got 46 knots, don't know if this is good or bad?
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Old 22 October 2007, 14:55   #2
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Not bad at all - sounds like a nice setup!!!
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Old 22 October 2007, 16:43   #3
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Did you trim the engine out for max speed?

Chris
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Old 22 October 2007, 16:47   #4
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seems pretty good to me. i get 49 from my 7.5 and same engine when trimmed right out.
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Old 23 October 2007, 04:32   #5
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Advice please,

What speed should I expect from this.....................

7.5M Cobra with 225hp Mercury Optimax with stainless 21 pitch prop.

1 person, 25 Gallons of fuel.

Been out today in flat conditions & got 46 knots, don't know if this is good or bad?

What RPM is it pulling at that speed?
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When a boat looks that good who needs tubes!!!
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Old 25 October 2007, 15:30   #6
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Country: UK - England
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Boat name: Max Power
Make: Cobra 7.5
Length: 7m +
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I think the RPM was about 4800.

The trim was 1.5.
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Old 26 October 2007, 08:40   #7
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I think the RPM was about 4800.

The trim was 1.5.
Trim doesn't really mean anything as each boat is different, but I think you'll find it should be revving a bit more than 4800 - did you try more trim or could you move some weight towards the back of the boat?

By the way if you have a 1: 1.87 gearbox that's about 2% slip which is amazing - could you have had a little help from the tide?
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When a boat looks that good who needs tubes!!!
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