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11-05-2007, 06:27 PM
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#1
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Registered User
Country: uk
Location: surrey
Occupation: Railway staff
Boat make: P23, P21, R20, RingRanger 25, Sabre
Engines: 225promax, xr2, EFI tuned, 6.2 mercruiser, suzuki 140 lol
Cruising area: littlehampton
Join Date: Aug 2005
Location: surrey
Posts: 358
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cavitating
my p23 with 225promax cavitates like mad when you give it some wellie, at any speed, its on a stainless steel leg running a four blade?
my dad said he found on here, sommin about different legs can do that?
any advise?? because it nearly cought us out in the chop last week, it was really rough tried to get back in over the chop it was just cavitating flat out and bogging down? but when she bites she does really shift?
any ideas
thanks
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speed speed and MORE SPEED!
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11-05-2007, 06:34 PM
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#2
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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Lewis aint cavatation when the engine is over revving/slipping not bogging out?
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Class 3C Mono EPA National speed record holder 95.35 mph Avg!
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11-05-2007, 06:38 PM
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#3
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Registered User
Country: uk
Location: surrey
Occupation: Railway staff
Boat make: P23, P21, R20, RingRanger 25, Sabre
Engines: 225promax, xr2, EFI tuned, 6.2 mercruiser, suzuki 140 lol
Cruising area: littlehampton
Join Date: Aug 2005
Location: surrey
Posts: 358
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yeah it might have just been the conditions on sunday made it feel like bogging out, but we get loads of revs and not much action? just curious, is it proped wrong?
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speed speed and MORE SPEED!
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11-05-2007, 06:50 PM
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#4
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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Maybe? When its flat what are the revs like? Got a jack plate? Engine to high?
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Class 3C Mono EPA National speed record holder 95.35 mph Avg!
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11-05-2007, 07:15 PM
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#5
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Registered User
Country: United kingdom
Location: West Sussex
Occupation: Grease Monkey
Interests: Makin my boat faster!
Boat name: S.B Racing
Boat make: Ocke mannerfelt canopied B23 / Zapcat
Engines: Merc 200XS Gen 2 / Tohatsu 50
Cruising area: littlehampton/Southampton
Join Date: Jan 2005
Location: West Sussex
Posts: 2,656
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Speak to cronky mate he knows his stuff.
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Class 3C Mono EPA National speed record holder 95.35 mph Avg!
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11-05-2007, 09:19 PM
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#6
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Registered User
Boat make: Phantom 23
Join Date: Mar 2006
Posts: 1,693
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What height is the engine? could you get a pic of the engine trimmed level with a peice of wood or something flat coming off the bottom of the v to the gearbox.
what prop do you have?
an offshore leg influences the prop to slip less as insted of all the exhaust going via the prop allowing it to spin up, the exhaust is released via the open exhaust
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12-05-2007, 09:26 AM
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#7
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Registered User
Country: England
Location: Plymouth
Boat make: Fletcher Arrowflyte
Engines: Mercury 75
Join Date: Nov 2004
Location: Plymouth
Posts: 402
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Cavitation is when the water 'boils' on the surface of the prop blades, meaning the prop doesn't bite/grip properly. It's usually caused by damage on the surface/edges of the prop blades & can be diagnosed by the fine pitting on the blade surface caused by the 'boiling' water.
Ventilation is when air is sucked down from the surface onto the prop, again causing it to slip. This is usually due to the engine being too high or trimmed out too far. Generally the anti-ventilation plate above the prop should be level with the bottom of the transom but higher performance boats like yours usually have it set slightly higher for less drag & more speed.
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12-05-2007, 09:53 AM
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#8
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Registered User
Country: uk
Location: surrey
Occupation: Railway staff
Boat make: P23, P21, R20, RingRanger 25, Sabre
Engines: 225promax, xr2, EFI tuned, 6.2 mercruiser, suzuki 140 lol
Cruising area: littlehampton
Join Date: Aug 2005
Location: surrey
Posts: 358
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thanks for getting back to me, it does it slightly when trimmed in aswell, i heard it does it to build revs, apparently the prop on it is for higher top end rather than accel
and she does have a nice rooster!!
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12-05-2007, 09:59 AM
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#9
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Registered User
Country: UK
Location: Weston Super Mare
Occupation: Electrical Engineer
Join Date: Mar 2004
Location: Weston Super Mare
Posts: 6,351
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I'd have thought you would want to be trimmed right in when rough anyway
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12-05-2007, 11:45 AM
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#10
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Registered User
Country: uk
Location: surrey
Occupation: Railway staff
Boat make: P23, P21, R20, RingRanger 25, Sabre
Engines: 225promax, xr2, EFI tuned, 6.2 mercruiser, suzuki 140 lol
Cruising area: littlehampton
Join Date: Aug 2005
Location: surrey
Posts: 358
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oh yea i knw, im was just saying in perfect conditions having the boat trimmed just right, she gives a nive rooster. which i dont knw why i really like
is it worth trying another prop? also she wont rev past 6,000-6,200 rpm, isnt it supposed to rev to 6,700??
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speed speed and MORE SPEED!
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12-05-2007, 11:58 AM
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#11
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Registered User
Boat make: Phantom 23
Join Date: Mar 2006
Posts: 1,693
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What prop do you have at the momeny?
all the props, engine heights etc have still slipped abit just something you have to put up with, after all it only slips for around 3 seconds then throws you back in your seat
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12-05-2007, 12:27 PM
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#12
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Registered User
Country: uk
Location: surrey
Occupation: Railway staff
Boat make: P23, P21, R20, RingRanger 25, Sabre
Engines: 225promax, xr2, EFI tuned, 6.2 mercruiser, suzuki 140 lol
Cruising area: littlehampton
Join Date: Aug 2005
Location: surrey
Posts: 358
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its currently on a four blade, unsure of pitch.
it slips for longer than three secs! also my old xr2 on ring 20 never used to, well not tht much anyway,
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speed speed and MORE SPEED!
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12-05-2007, 12:29 PM
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#13
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Registered User
Boat make: Phantom 23
Join Date: Mar 2006
Posts: 1,693
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are you trimmed right in when its slipping?
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12-05-2007, 02:41 PM
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#14
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Registered User
Country: uk
Location: surrey
Occupation: Railway staff
Boat make: P23, P21, R20, RingRanger 25, Sabre
Engines: 225promax, xr2, EFI tuned, 6.2 mercruiser, suzuki 140 lol
Cruising area: littlehampton
Join Date: Aug 2005
Location: surrey
Posts: 358
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yeah, it happens at all angles of tilt!
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speed speed and MORE SPEED!
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12-05-2007, 03:20 PM
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#15
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Registered User
Boat make: Phantom 23
Join Date: Mar 2006
Posts: 1,693
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Is the prop damaged at all?
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12-05-2007, 07:09 PM
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#16
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Registered User
Country: England
Location: Birmingham
Occupation: Scratching
Interests: Big Dinners
Boat name: Never Enough
Boat make: Seaquel 600xs
Engines: 225hp Merc ProMax
Cruising area: Anywhere! I prefer Weymouth
Join Date: May 2005
Location: Birmingham
Posts: 3,232
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As this happens in all trim conditions it may be that the hub is slipping.
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I got jumper cables!
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12-05-2007, 07:13 PM
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#17
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Registered User
Boat make: Phantom 23
Join Date: Mar 2006
Posts: 1,693
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Quote:
Originally Posted by MrRob
As this happens in all trim conditions it may be that the hub is slipping.
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How can the hub slip?
If the hub was broke he would have no drive or no prop
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12-05-2007, 07:16 PM
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#18
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Registered User
Country: England
Location: Birmingham
Occupation: Scratching
Interests: Big Dinners
Boat name: Never Enough
Boat make: Seaquel 600xs
Engines: 225hp Merc ProMax
Cruising area: Anywhere! I prefer Weymouth
Join Date: May 2005
Location: Birmingham
Posts: 3,232
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Quote:
Originally Posted by PuppiesBalls
How can the hub slip?
If the hub was broke he would have no drive or no prop
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As the hub of the prop gets old and worn they can slip. I had to have my old Laser II rehubbed when I 1st had it as it slipped like a bastard.
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I got jumper cables!
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12-05-2007, 07:38 PM
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#19
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Registered User
Boat make: Phantom 23
Join Date: Mar 2006
Posts: 1,693
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Ahh i understand
I just had the image of the Flowtorque hub in my mind and couldn't see how it could slut
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12-05-2007, 08:36 PM
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#20
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Registered User
Country: uk
Join Date: Nov 2006
Posts: 308
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Quote:
Originally Posted by TheOrs
Cavitation is when the water 'boils' on the surface of the prop blades, meaning the prop doesn't bite/grip properly. It's usually caused by damage on the surface/edges of the prop blades & can be diagnosed by the fine pitting on the blade surface caused by the 'boiling' water.
Ventilation is when air is sucked down from the surface onto the prop, again causing it to slip. This is usually due to the engine being too high or trimmed out too far. Generally the anti-ventilation plate above the prop should be level with the bottom of the transom but higher performance boats like yours usually have it set slightly higher for less drag & more speed.
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YES Great somebody else has this correct.
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