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07-07-2017, 11:31 AM
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#1
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Registered User
Country: England
Location: Lymington
Boat make: Technohull 888
Engines: Verado 300
Cruising area: Solent
Join Date: Jun 2017
Location: Lymington
Posts: 26
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Stepped hull trim advise
Hi, can anyone give me some advice. I recently got a Pascoe SR8 with a stepped hull. Ive done some work to it such as new shock mitigation seats so can go quicker if chop. But I can help but feel that there is more speed in it. I can get 56-57 knots but after that, the back end gets very light and then have to back off the power.
Has anyone go any advice with stepped hull trimming, engine heights, ballast etc..
Thanks
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08-07-2017, 09:45 PM
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#2
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Registered User
Location: West Coast of Norway
Occupation: naval architect
Interests: surface piercing props, stepped hulls, air entrapment hulls
Boat name: none
Boat make: PetterTintorera
Engines: Yamaha 90
Cruising area: West Coast of Norway
Join Date: Sep 2005
Location: West Coast of Norway
Posts: 888
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what prop and engine height?
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09-07-2017, 02:06 PM
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#3
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Registered User
Country: England
Location: Lymington
Boat make: Technohull 888
Engines: Verado 300
Cruising area: Solent
Join Date: Jun 2017
Location: Lymington
Posts: 26
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It's got a Solas 15 ⅛ x 23 and as far as can tell, the cavitation plate is about 2" above the bottom of the keel. It's hard to tell as the boats in the water. With the current setup, the engine hits its max RPM with about half an inch left to push the throttle forward. When that happens, the engine looses power until it goes down to about 4,000 rpm then begins to climb again.
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15-07-2017, 10:19 AM
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#4
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Registered User
Country: england
Location: southampton
Occupation: engineer
Interests: lots
Boat make: scorpion 8.1
Engines: 250HO
Cruising area: solent
Join Date: Mar 2004
Location: southampton
Posts: 1,353
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Which sr8 is it? I'd expect more speed. My mate had the one with air holes in the steps and it used to max out around 70-72mph from memory. He had an old tuned merc on it.
If he lifted the engine too high on jack plate it got pretty loose. It had a bow tank but he never needed it, I think they run level cause of the step hull like a b24
I'll ask him what prop and height he ran, it was a pig to plane though as cavitation.
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16-07-2017, 08:00 PM
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#5
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Registered User
Location: West Coast of Norway
Occupation: naval architect
Interests: surface piercing props, stepped hulls, air entrapment hulls
Boat name: none
Boat make: PetterTintorera
Engines: Yamaha 90
Cruising area: West Coast of Norway
Join Date: Sep 2005
Location: West Coast of Norway
Posts: 888
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Quote:
Originally Posted by James_Levitt-Cooke
It's got a Solas 15 ⅛ x 23 and as far as can tell, the cavitation plate is about 2" above the bottom of the keel. It's hard to tell as the boats in the water. With the current setup, the engine hits its max RPM with about half an inch left to push the throttle forward. When that happens, the engine looses power until it goes down to about 4,000 rpm then begins to climb again.
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I would lift the engine much more and get a nice cleaver. Maybe contact Mr Pascoe for advise.
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17-07-2017, 09:27 AM
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#6
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Registered User
Country: England
Location: Lymington
Boat make: Technohull 888
Engines: Verado 300
Cruising area: Solent
Join Date: Jun 2017
Location: Lymington
Posts: 26
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Is he on here do we know? I tried emailing him a couple of weeks ago but didn't hear anything back. Anyone have his email the could pm me?
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17-07-2017, 12:27 PM
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#7
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Registered User
Country: england
Location: southampton
Occupation: engineer
Interests: lots
Boat make: scorpion 8.1
Engines: 250HO
Cruising area: solent
Join Date: Mar 2004
Location: southampton
Posts: 1,353
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Don't think he is on here. Is urs same boat?
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17-07-2017, 12:58 PM
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#8
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Registered User
Country: England
Location: Lymington
Boat make: Technohull 888
Engines: Verado 300
Cruising area: Solent
Join Date: Jun 2017
Location: Lymington
Posts: 26
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Quote:
Originally Posted by glen76
Don't think he is on here. Is urs same boat?
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Yep, I think mine was the SR8 used as a demo bare hull. I saw his in Yarmouth the other day. He's done his up a bit more though. He reckoned he got 80mph out of his. I'm only getting 67mph! He has a verado 350 on the back but way more weight on board and a much heavier engine.
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