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Old 07-02-2010, 11:33 PM   #1
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Country: UK
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Boat name: Athito
Boat make: Sunseeker Superhawk 34
Engines: 2x300hp Yanmar 6LP
Cruising area: Solent

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Nose cones on Bravo III drives - any use?

Have been reading Offshore Only and seen some mixed reports about nose cones like http://www.bobsmachine.com/products/cones.cfm

Primarily they seem to suggest:
-1- they're only useful in 80-90mph and above
-2- they can introduce some wayward handling characteristics

They seem like a small spend ($134 each) and if they'll get me a few more knots that seems like a good deal.


Boat is a Sunseeker Superhawk seeing a top end of 42-43 knots.

2x Yanmar 6LPA-STZP 300hp on Bravo3 drives Ratio 1.65:1 and standard Mercruiser 26" props.
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Old 08-02-2010, 12:52 AM   #2
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Country: Ireland
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Boat make: Hydrostream V-king, 650SS OCR ,Ring 21, Ring 18, Phantom 18.
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They wont gain, probably cost you if anything.
You dont need the increased aspect ratio for your speed.

Nose cones are usually only added for either low water pick up or to stop blowout on stock length cases, usually above 80mph.

I dont know a lot about big boats and I/Bs but my opinion your best bet for more speed would be either surface drives or reduce weight or both.

Alan
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Old 08-02-2010, 01:31 AM   #3
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Country: UK
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Boat name: Athito
Boat make: Sunseeker Superhawk 34
Engines: 2x300hp Yanmar 6LP
Cruising area: Solent

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Thanks for the feedback....and the aspect ratio/speed comment starts to answer some of the OSO comments about 80-90mph+ so cheers for that background.

Surface drives: yes but they're £20k++++ (I was looking for a smaller spend until I repower completely)

Reduce weight: yes...you're right, but no can do without completely alienating the Mrs!!

The boat is a "fast cruiser"....and needs to have some ability to weekend on, shower and sleep...
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Old 08-02-2010, 01:35 AM   #4
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Quote:
Originally Posted by Athito View Post

Reduce weight: yes...you're right, but no can do without completely alienating the Mrs!!
Well that's even less weight
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Old 08-02-2010, 08:20 AM   #5
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All nosecones would do on your boat, is cost you time and money, with no speed difference whatsoever. Hydrostream is bang on the money.

We ran 80 with a stock Bravo lower, then tried a Bobs Machine shop cone. All it did was mess with the handling. probably as our boat needed an awfull lot of positive trim, so we weren't dragging the bullet through the water straight. so the extended length was detrimental.

Maybe a stepped boat (possibly no positive trim required) running in excess of 80 would benefit. But below that sort of figure, I think a stock lower will be more forgiving in lots of ways and no slower.
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