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12-02-2008, 08:38 PM
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#1
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Registered User
Country: Spain
Join Date: Sep 2005
Posts: 1,726
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What causes this?
At about 29 seconds into the run.....
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12-02-2008, 09:08 PM
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#2
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Registered User
Country: England
Location: Hampshire
Occupation: Credit Crunched
Interests: Rally Driving
Boat name: Double 2 Shirts
Boat make: Planatec 41
Engines: 2x625's+ From Uncle Sam
Cruising area: Solent
Join Date: May 2007
Location: Hampshire
Posts: 2,522
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Drag from the Sponsons (At least that's what I think - for whats its worth - Which may not be much - but who cares) 
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12-02-2008, 09:36 PM
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#3
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Registered User
Occupation: Champion Pie Eater
Boat name: On The Rocks
Boat make: Ring 21 marshan 17 four winns horizon, hydro 3 pointer, f2 cat, backdraft 22
Cruising area: Way up norf and Sarf coast areas
Join Date: Apr 2007
Posts: 1,619
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Could it be a side wind or overcorrection,
Jon will know.
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12-02-2008, 09:38 PM
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#4
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Registered User
Country: UK
Occupation: dog breeder
Interests: boats, cars,film.f1 and anitques/paintings
Boat name: tba
Cruising area: south coast France and med
Join Date: Apr 2007
Posts: 1,062
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It could simpley be a gust of wind, at those speeds only a few inches are in contact with the water surface, so running with onl props semi emersed the craft will wander at the slightes bit of wind!!!!!!!!!!!! me tinks 
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12-02-2008, 10:18 PM
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#5
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Registered User
Country: Ireland
Location: Dublin
Occupation: Boatbuilder
Boat make: Hydrostream V-king, 650SS OCR ,Ring 21, Ring 18, Phantom 18.
Engines: 300Hp Mercury 2.4, 130 Yamaha, Bridgeport EFI, XR6, Merc 200.
Cruising area: Malahide, Dublin
Join Date: May 2004
Location: Dublin
Posts: 1,803
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Watch the back of the tunnel, looks like the tunnel tab comes down and lifts the back a little too much.
Alan
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12-02-2008, 10:23 PM
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#6
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Registered User
Country: England
Location: Hampshire
Occupation: Credit Crunched
Interests: Rally Driving
Boat name: Double 2 Shirts
Boat make: Planatec 41
Engines: 2x625's+ From Uncle Sam
Cruising area: Solent
Join Date: May 2007
Location: Hampshire
Posts: 2,522
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It Happens to me at that sort of speed - its sponson drag - trust me - im a Lawyer 
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12-02-2008, 10:46 PM
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#7
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numbskull
Country: United Kingdom
Location: South
Occupation: none
Interests: none
Boat name: Leviathan
Boat make: Phantom 28
Cruising area: South Coast
Join Date: Mar 2004
Location: South
Posts: 15,959
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Looks to me like he runs across a slight 3/4 swell, maybe from a spectator boat.
__________________
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"I Agree with everything you say really!" - John Cooke to Jon Fuller - 26-01-2013
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12-02-2008, 11:30 PM
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#8
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Registered User
Join Date: Mar 2004
Posts: 6,891
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80% or so of the boat's lift could be aerodynamic at those speeds.
There ain't much sticking in the water, so only a minor disturbance (swell as suggest by Jon for example) is needed to unbalance the rig. Especially if one of the "dart flights" (skegs) momentarily breaks the surface.
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12-02-2008, 11:34 PM
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#9
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Registered User
Join Date: Mar 2004
Posts: 6,891
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What you're talking about is the classic cat getting big air, coming down 1 side, sponson drag massively decelerating that side which puts the boat into a sharp turn & high side. Unsure what impact driver input would have to save it, but my theory is keep yer foot down and steer into it.
Quote:
Originally Posted by Pash 1
It Happens to me at that sort of speed - its sponson drag - trust me - im a Lawyer |
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13-02-2008, 07:34 AM
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#10
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Registered User
Join Date: Mar 2004
Posts: 1,016
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Quote:
Originally Posted by Pash 1
It Happens to me at that sort of speed - its sponson drag - trust me - im a Lawyer |
Trust me?... Lawyer?...Hahahahahaha....
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13-02-2008, 10:27 AM
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#11
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Registered User
Country: UK
Location: Windermere
Join Date: Oct 2005
Location: Windermere
Posts: 559
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Prop Walking
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13-02-2008, 01:20 PM
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#12
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Registered User
Country: Spain
Join Date: Sep 2005
Posts: 1,726
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Looks to be one hell of a ride!
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13-02-2008, 05:17 PM
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#13
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Senior Member
Country: netherlands
Location: Mijdrecht/holland
Occupation: truck repair
Interests: fast boats/porches
Boat name: bernico cat
Boat make: bernico 26 cat 2x 2,5,s
Engines: merc,s 2,5 EFI,s
Cruising area: ijselmeer
Join Date: Dec 2005
Location: Mijdrecht/holland
Posts: 382
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Me think it has to do something like Alan said ,it looks like it is packing so much air , the whole boat was pushed upwards so much that all the weight was just overcome by the pressure in the tunnel,and causes to lift the lightest sponson first ,and lifted possibly the prop out of the water which causes that strange unwanted change of direction.....
When driving on the edge ,you just want your props in the water ,if the prop comes out ,it can make your day real bad.
It could also that they were testing propellors with different stern lifting abilities,or changes in the drive height ,dunno what sort drives ,could be #6 ,s or BPM drives .
Was that the boat that ran 202 mph ?
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14-02-2008, 12:31 AM
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#14
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Registered User
Country: Ireland
Location: Dublin
Occupation: Boatbuilder
Boat make: Hydrostream V-king, 650SS OCR ,Ring 21, Ring 18, Phantom 18.
Engines: 300Hp Mercury 2.4, 130 Yamaha, Bridgeport EFI, XR6, Merc 200.
Cruising area: Malahide, Dublin
Join Date: May 2004
Location: Dublin
Posts: 1,803
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Quote:
Originally Posted by sterling
Was that the boat that ran 202 mph ?
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It's the Bacardi Silver boat
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