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Old 27 August 2019, 04:18   #1
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Country: UK - England
Town: Little Easton
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Make: Excel Virago
Length: 4m +
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Rib Nose up???

Can anyone help. I have a 4.2m rib with a mercury 60 four stroke. When in harbour at 6knts it sits nice and flat. Above this the nose sticks up ridiculously Like itís trying to push under itself until it planes. Can anyone offer advice regarding engine position/trim/anything to improve this. If I try to pull a skier out the whole (heavy 95kg sods like me) the boat pitches nose up and struggles to get on the plane and acts more like a damn!

Engine height? Up or down? Would this help? All technical/practical advice appreciated.
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Old 27 August 2019, 04:26   #2
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Hydraulic or fixed trim?
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Old 27 August 2019, 04:37   #3
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Quote:
Originally Posted by cheeseboat View Post
Can anyone help. I have a 4.2m rib with a mercury 60 four stroke. When in harbour at 6knts it sits nice and flat. Above this the nose sticks up ridiculously Like itís trying to push under itself until it planes. Can anyone offer advice regarding engine position/trim/anything to improve this. If I try to pull a skier out the whole (heavy 95kg sods like me) the boat pitches nose up and struggles to get on the plane and acts more like a damn!

Engine height? Up or down? Would this help? All technical/practical advice appreciated.
I assume the engine isnít too heavy......and the weight on the boat is at least central or preferably forward.....and the motor is trimmed in....if those basics are ok you may need to look at fitting some wedges for the engine mounts.... itís also asking a lot for a 4.2 m boat to be comfortable in pulling out a95 kg skier..
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Old 27 August 2019, 04:45   #4
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Right leg length.....L, XL..? Prop set too deep ?.
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Old 27 August 2019, 05:02   #5
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Country: UK - England
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Originally Posted by Iankristy View Post
Hydraulic or fixed trim?


Thanks for responding

Itís hydraulically trimmed. Trimmed full down.
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Old 27 August 2019, 05:04   #6
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Country: UK - England
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I assume the engine isnít too heavy......and the weight on the boat is at least central or preferably forward.....and the motor is trimmed in....if those basics are ok you may need to look at fitting some wedges for the engine mounts.... itís also asking a lot for a 4.2 m boat to be comfortable in pulling out a95 kg skier..


I think yes to those basics but need to check properly.

So would wedges to push the top of the engine back be worth a try?
I never need to trim up when planing.
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Old 27 August 2019, 05:05   #7
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Country: UK - England
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Originally Posted by cheeseboat View Post
I think yes to those basics but need to check properly.

So would wedges to push the top of the engine back be worth a try?
I never need to trim up when planing.


And yes, I appreciate itís asking a lot! I would loose weight but drinking and eating too much is for more inviting 🤣🤣🤣
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Old 27 August 2019, 05:07   #8
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Country: UK - England
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Originally Posted by Last Tango View Post
Right leg length.....L, XL..? Prop set too deep ?.


The ďventilationĒ (I thinks thatís what itís called) plate (the bottom flat fin) is roughly level wth the bottom of the transom.
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Old 27 August 2019, 05:36   #9
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The centre of gravity may be too far back I had same problem with my 4m Avon.with a 4stroke 40HP
On plane engine should be trimmed up c.halfway

I'd move what weight I can -batttery, fuel, etc. forward & see what effect that has.

Have you considered fitting Doelfins? - I found they made a huge difference.

Think about some ballast in bow as a further option

LT
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Old 27 August 2019, 05:59   #10
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RIBase
very low powered engine to pull a 95Kg skier but it sounds like you have other issues at play to sort out first.
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