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Old 24 April 2008, 21:23   #1
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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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Old 24 April 2008, 23:37   #2
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Sounds odd. Got pics?

Does the transom have a cut out?
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Old 25 April 2008, 02:10   #3
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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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Old 25 April 2008, 03:14   #4
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searider transom

agree with Nos, these pics might help
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Old 25 April 2008, 03:25   #5
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thought these pictures might help too!!!
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Old 25 April 2008, 03:46   #6
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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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Old 25 April 2008, 06:48   #7
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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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Old 25 April 2008, 08:57   #8
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Quote:
Originally Posted by mcinfantry View Post
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....
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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Old 25 April 2008, 09:35   #9
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Quote:
Originally Posted by Locozodiac View Post
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
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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Old 25 April 2008, 11:57   #10
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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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Old 25 April 2008, 22:54   #11
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Originally Posted by Nos4r2 View Post
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.
got back a couple hours ago...

ok, its more than 1" higher than bottom...... but the mount touches the transom. ran the boat, and it runs strong... i forgot my gps, BUT, with a stainless prop (i dont know size) and two men on board, 450#total and 25 gallons fuel, yes..... 25 gallons, the speedo showed 45mph max speed. 44 was easy to hit.....

so.... in turns she cavitates more than i would like, but ill run it tomorrow and get used to it.. plus ill have more passengers..... and of course the gps.
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Old 03 July 2008, 08:49   #12
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just to put this up for future reference for searider guys...

as received from avon
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Old 03 July 2008, 16:26   #13
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Hi there,
looks to me, that you have a transom for twin engine .

Mike
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Old 14 August 2008, 09:26   #14
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Wiyh the anti-ventilation plate set 1" above the hull bottom, I think your engine and transom are perfectly matched.
The speed seems good too.
If you wanted to increase the top speed and overall boat behaviour, I would suggest to use a Powertech SS prop, PTR3 or OSN3 with the right pitch to go to the max power rpm
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