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ONE FOR THE TECHIES
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Out in Torbay for first trip yesterday.
Sea like a mirror, nice breeze, 4000 revs and could I get her much above 10 knots - nah. Boat is as clean as you like having just been antifouled. Full service by Yanmar/Mercruiser agent. Prop absolutey clean and free running. Bravo One leg and all fitted to a Monterey 250CR which is a 30 knot boat, or rather it should be.
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BarryH
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(regular)
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11/05/2008 21:28
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Re: ONE FOR THE TECHIES
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How much BHP, petrol/diesel? Weight distribution? Lots of things affect performance. I had weed wrapped on the outdrive which stopped me getting on the plane and it was no more than a large handful.
Over the years the boat got loadded with more an more kit. Wet suits ringo's and water toys, tender 2 outboards??? and load of other stuff. I drank the beer and had a good sort out. I reckon that I've added five knots of lost topend....
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DavidJ
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(regular)
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11/05/2008 21:43
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Re: ONE FOR THE TECHIES
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Volvo props and probably the others have a rubber cushion between the internal spline and the prop (you can't see it) If the rubber shears it would have the effect you describe.
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Re: ONE FOR THE TECHIES
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Theres a lot of torque through a Bravo leg, as mentioned above its possible the bush on the prop. Send it to Steel Developments to get it fixed.
Other possibility is simply poor loading. Did you have the leg fully trimmed in, trim tabs down ? On cruisers of this size its essential to get weight into the bow to get them on the plane, especially if you are fully loaded -fuel, tender, water etc. Put the crew up front to get the boat going then they can come back out to the cockpit.
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Re: ONE FOR THE TECHIES
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Well - thats Devon for you - everything's slow.
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Re: ONE FOR THE TECHIES
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Had the same problem on a searay I owned a while back. All revs and no go. I put a new prop on and it was sorted. Merc ally props seem to shear their rubber torque inserts with the result the shaft spins but the prop spins much slower.
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Re: ONE FOR THE TECHIES
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Three adults, one 9 year old, half fuel, no tender etc.
Same loading last season and 25 knots. Tried all trimming options with little effect.
Seems that the likely cause is slipage on the props rubber bearing housing, although there is a suggestion that there may be a rubber cone on the engine output, which may be the problem.
Its a stainless prop which is coming off and another put on to check performance.
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