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25 April 2008, 02:23
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#1
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Member
Country: USA
Town: near baton rouge
Make: avon
Length: 5m +
Engine: 90hp etec
Join Date: May 2007
Posts: 44
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5.4m searider engine height and offset?
ok, i have a short shaft etec 75 and a 5.4m searider.
i know why they have offset, is general reccomendation for the 5.4m searider still 1"? mine is dead center.
what height does the "cavitation" plate need to be. im trying to run a "maiden voyage" tomorrow, and mine is SEVERAL inches above the bottom of the "v". i am starting to wonder if my searider was/is set up for a longer than 20" shaft?????
can i cut the transom and lower the motor? what "too low" whats avg water line height from the bottom of the v at the transom to the water line?
please, help asap....
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25 April 2008, 04:37
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#2
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RIBnet admin team
Country: UK - England
Town: Swindon
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 239050687/235055163
Join Date: Jul 2005
Posts: 8,881
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Sounds odd. Got pics?
Does the transom have a cut out?
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25 April 2008, 07:10
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#3
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Member
Country: UK - England
Town: Scillies
Boat name: Freedom
Make: Searider
Length: 5m +
Engine: Yam 2st 90
Join Date: Jan 2007
Posts: 335
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I'm with Nos. Only way a short shaft is going to fit is if the transom has been cut down which means you will ship a lot of water.
Ian
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25 April 2008, 08:14
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#4
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Member
Country: UK - England
Town: Bristol
Make: Avon
Length: 5m +
Engine: Yamaha
Join Date: May 2006
Posts: 1,853
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searider transom
agree with Nos, these pics might help
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25 April 2008, 08:25
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#5
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Member
Country: UK - England
Town: Bristol
Make: Avon
Length: 5m +
Engine: Yamaha
Join Date: May 2006
Posts: 1,853
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thought these pictures might help too!!!
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25 April 2008, 08:46
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#6
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Member
Country: Netherlands
Town: Holland
Make: Brig F360S
Length: 3m +
Engine: Yamaha 70hp
Join Date: Jan 2008
Posts: 85
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As far as I know there are only 20" (longshaft), 25" (extra longshaft), 30" (ultra longshaft) E-Tec 75hp. What could be the problem is that you're transom is 25" and you have a 20" shaft on your engine. I won't cut out the transom, but fit a setback on you're transom so that you easily can lower and raise the engine without cutting.
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25 April 2008, 11:48
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#7
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Member
Country: USA
Town: near baton rouge
Make: avon
Length: 5m +
Engine: 90hp etec
Join Date: May 2007
Posts: 44
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hmmm.. im confused. im positive my motor is 20", and its on the lowest (as in motor is as low as it can go) setting. so the searider is supposed to have a 20" shaft or 25" motor?
ill update. going to get it at the boat shop now....
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25 April 2008, 13:57
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#8
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Member
Country: Other
Town: Lima-Peru
Boat name: Nautile
Make: Sea Rider Boats
Length: 4m +
Engine: Tohatsu 18 /30 HP
Join Date: Sep 2007
Posts: 764
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Quote:
Originally Posted by mcinfantry
ok, i have a short shaft etec 75 and a 5.4m searider.
i know why they have offset, is general reccomendation for the 5.4m searider still 1"? mine is dead center.
what height does the "cavitation" plate need to be. im trying to run a "maiden voyage" tomorrow, and mine is SEVERAL inches above the bottom of the "v". i am starting to wonder if my searider was/is set up for a longer than 20" shaft?????
can i cut the transom and lower the motor? what "too low" whats avg water line height from the bottom of the v at the transom to the water line?
please, help asap....
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Get yor engine specs, some manuals mentions best engine height performance between boat's bottom to anticavitation plate. Your engine leg length must match your rib transom height. Had a tremendous amount of water splashing against the leg and into the sib's interior, in my case have risen the transom, now inside the engine range distance and solved the problem for ever with excellent water performance.
Don't think you can apply this principle to ribs as you do with sibs because of the deep v hull. Anyway there might be information available on best performer height tollerance distances, or ask the manufacturers. Maybe need a long shaft 20" engine to match your rib's transom height. Cutting down a perfect horizontal transom is a hell of a job than rising it.
Happy Boating
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25 April 2008, 14:35
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#9
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Member
Country: Netherlands
Town: Holland
Make: Brig F360S
Length: 3m +
Engine: Yamaha 70hp
Join Date: Jan 2008
Posts: 85
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Quote:
Originally Posted by Locozodiac
Get yor engine specs, some manuals mentions best engine height performance between boat's bottom to anticavitation plate. Your engine leg length must match your rib transom height. Had a tremendous amount of water splashing against the leg and into the sib's interior, in my case have risen the transom, now inside the engine range distance and solved the problem for ever with excellent water performance.
Don't think you can apply this principle to ribs as you do with sibs because of the deep v hull. Anyway there might be information available on best performer height tollerance distances, or ask the manufacturers. Maybe need a long shaft 20" engine to match your rib's transom height. Cutting down a perfect horizontal transom is a hell of a job than rising it.
Happy Boating
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There is no such thing as a best height for outboards, that's different from boat to boat, and even the kind of prop you uses changes this. If you use a standard aluminium prop, you're prop starts cavitating inmediatelly when it rises slightly above the water. A 'normal' SS-prop can drive nearer the surface, inches above it if you want. Special propellors like choppers or cleavers made for extreme speeds are usually with one half above and with one half under the water surface...
In think the case here is: engine has a standard longshaft 20", the transomheight is 25", so you need to lower the engine somewhat for normal applications. What you can do is mounting a bracket, in order to lower your engine without cutting in you're transom. As a 'bonus' it gives you a somewhat higher topspeed. I suggest measuring you're transom and talk with some blokes at the boatshop about the mounting of a bracket.
Something like this:
http://continuouswave.com/whaler/ref...ate549x640.jpg
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25 April 2008, 16:57
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#10
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RIBnet admin team
Country: UK - England
Town: Swindon
Boat name: WhiteNoise/Dominator
Make: Ballistic 7.8/SR5.4
Length: 7m +
Engine: Opti 225/Yam 85
MMSI: 239050687/235055163
Join Date: Jul 2005
Posts: 8,881
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Post a pic of the transom. I can give you a definitive answer then. The twin engine 5.4 seariders don't have a cutout AFAIK.
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