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Old 24-03-2006, 04:33 PM   #1
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Twin Engines

As some of you know I have twin 4stroke 115hp Yamaha (one counter rotating) engines on my rib. I am looking at replacing them... mainly so I can get a new 3 year warranty (and of course to get a bit more speed/faster acceleration )

A certain engine sales company up north has told me that if my engines are under 200hp then I do not need to worry about having one of the engines counter rotating - I just wanted to verify that this is the case?

Also, on another note, does anyone else have any other suggestions about things I need to consider when getting new engines? Someone mentioned to me before about offsetting them to get better handling/speed?

Thanks

Ben
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Old 24-03-2006, 04:38 PM   #2
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That means the dealer doesn't have any left handers in stock!

Load'a bollix, you definitely want counter rotating motors.

Engine offset isn't something you need to worry about with a twin instalation (unless they're both right handers, in which case I wouldn't know where to start )

JF
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Old 24-03-2006, 04:44 PM   #3
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Quote:
Originally posted by Jon Fuller
That means the dealer doesn't have any left handers in stock!

Load'a bollix, you definitely want counter rotating motors.
Thought so, barnet marine seem to know what they're doing with R*bs

The engine offset I was told about was for twins, was told they could both be slightly offset against each other - im not sure what the reason was.... maybe to stop the flow of water from the prop's affecting each other ?
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Old 24-03-2006, 05:06 PM   #4
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Quote:
Originally posted by benc
was told they could both be slightly offset against each other -
I don't really understand that! mebbe i'm stoopid, but they can't exactly be on the same centerline can they? .....maybe it's a 'RIB' thing.
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Old 24-03-2006, 05:18 PM   #5
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Ok ok, I'm no good at explaining things

What I mean is that the left engine would be slightly tilted to the right, and the left engine slightly to the right, to move the propellers away from one another...

I can't remember who I was talking to about it... I'll shut up now
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Old 24-03-2006, 05:35 PM   #6
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Quote:
Originally posted by benc
...What I mean is that the left engine would be slightly tilted to the right, and the left engine slightly to the right, to move the propellers away from one another...Ok ok, I'm no good at explaining things
You got that right. I think you mean the right one tilted to the left. Anyway, I recollect that from somewhere but I've no idea what the thinking is. I've a feeling it was something to do with those South African catamaran ribs.

You might want to toe them in or out a tad to preload the steering.
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Old 24-03-2006, 05:40 PM   #7
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Quote:
Originally posted by jw.
You got that right. I think you mean the right one tilted to the left. Anyway, I recollect that from somewhere but I've no idea what the thinking is. I've a feeling it was something to do with those South African catamaran ribs.

You might want to toe them in or out a tad to preload the steering.

its a busy day in the office, have actually got some work to do, is due on the 15march :O ah well, thats what I get when trying to bring 4 teams together to get a simple thing done! bloody "big" companies!!!


could have done it all myself, but no... we have to use our legacy software to do this, and this other bit of code to do that... and so it goes on and on until we spend 10 times as long getting old things to work in a long way as it would take to write it from scratch.....

*rant over*


thanks jw
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Old 25-03-2006, 01:45 AM   #8
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Quote:
Originally posted by benc

I can't remember who I was talking to about it... D
You were talking to Adam Wheeler/ Radar from Zapcats
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Old 25-03-2006, 01:46 AM   #9
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Ah thats it!
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