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Old 29 August 2007, 10:07   #11
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Country: UK - Scotland
Boat name: Wildheart
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No PTT on mine , but echoing the "load postitioning" comments, I have 2 30L Hulk tanks, and although my speed is only "perceptively" more when I empty the bow tank first, the handling is far more responsive & wheel lighter. (must get a GPS.....)

I have also played with the pin position, and can also agree with the trim up comments, granted I have to fiddle about in the water whilst hanging over the transom to make the adjustment! I've left mine in the top notch, although do occasionally bring it down one hole if I'm solo with only one tank aboard.

Granted it's a relatively small RIB, so loosing 30L of fuel from the bow does raise the nose quite a lot!
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Old 29 August 2007, 10:46   #12
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Originally Posted by bedajim View Post
But slower
4 bladers knock a few mph off the top end but give better low end thrust and supposedly a more "stable" mid range (can't say I noticed that bit)
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Old 29 August 2007, 13:38   #13
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thanks for the advice & I looked at the ob setup today, it sits on about the middle or lower hole. If raising up a hole or 2 gives faster top speed, what is this at the expense of? thanks, donīt want to rush into raising it & finding itīs more unstable at mid range, which is where we are mainly using it.

Cheers all
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Old 29 August 2007, 13:42   #14
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Rising it up will give you less acceleration and more ventilation of the prop in turns etc. having said that it all depends on the boat - some like the outboard higher than others. That is why some people use a transom jack.
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Old 30 August 2007, 04:25   #15
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Originally Posted by RibinSpain View Post
thanks for the advice & I looked at the ob setup today, it sits on about the middle or lower hole. If raising up a hole or 2 gives faster top speed, what is this at the expense of? thanks, donīt want to rush into raising it & finding itīs more unstable at mid range, which is where we are mainly using it.

Cheers all
There seemed to be zero ill effects from relocating the engine to the top hole. It actually changed the noise of the engine, it went from sounding sort of "drowned" to sounding quite "rorty" and powerful.
Don't forget I did this in combination with a new 4 blade SS prop - I never tried the standard ali prop once the engine had been raised but suspect the SS prop was an integral part of the set up. I would talk to Steel Developments if you intend to raise the engine, tell them what you have, engine revs etc and see what they say.....
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Old 30 August 2007, 07:17   #16
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Quote:
Originally Posted by RibinSpain View Post
thanks for the advice & I looked at the ob setup today, it sits on about the middle or lower hole. If raising up a hole or 2 gives faster top speed, what is this at the expense of? thanks, donīt want to rush into raising it & finding itīs more unstable at mid range, which is where we are mainly using it.

Cheers all
What hole the engine is set to is irrelevant surely? what you need to look at is the cavitation plate in relation to the bottom of the transom. if the cav plate is about an inch above the bottom of the transom then you probably won't want to raise the engine any further without risking cavitation however if the cav plate is at the same height as or lower than the bottom of the transom then you may be in a position to do so.

Am i right in saying this?

Chris
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Old 30 August 2007, 07:25   #17
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What hole the engine is set to is irrelevant surely? what you need to look at is the cavitation plate in relation to the bottom of the transom. if the cav plate is about an inch above the bottom of the transom then you probably won't want to raise the engine any further without risking cavitation however if the cav plate is at the same height as or lower than the bottom of the transom then you may be in a position to do so.

Am i right in saying this?

Chris
I think you are right in what you are saying, but because I had exactly the same boat/engine package then I guess the engine would sit at the same height on his boat as mine hole for hole ?
The top hole did put the cavitation plate right level with the bottom of the V
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Old 30 August 2007, 10:16   #18
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I assume we are all talking about the same adjustment here? The pin is the one that the engine "sits" against when pushing the boat along, and the anti- lift catch engages on? Raising the cav plate above the transom surely would involve unbolting the engine from the transom & puting in packing pieces / drilling more holes to raise it?

I ask because altering mine will simply alter the engine angle relative to the transom, or put another way, alter the vertical thrust angle of the engine. Being a SR, if I tuck it to the bottom hole, then as the transom in far from vertical it means the prop is trying to cimb out the water, stern gets pushed up, and the bow goes down. (quite unnervingly so!) The top / second top holes mean the engine is vertical - ish and so something approaching equilibrium is met!

I reckon mine needs another 20 or so horses to get it planing enough to get it high enough out the water enough to worry about the prop popping out, chine walking and all the other nice problems you guys have been talking about! What's your Engine like in the HP dept compared to the boat's rated max? If you're miles awaylike me then I guess that's one of the reasons you've not had any ill effects?
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Old 30 August 2007, 12:47   #19
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mine is 115hp boat is rated for 150hp and feels like it could easily handle more though I would not like to add a hell of a lot more weight on the stern and then be in a following sea...
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Old 30 August 2007, 14:24   #20
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Quote:
Originally Posted by 9D280 View Post
I assume we are all talking about the same adjustment here? The pin is the one that the engine "sits" against when pushing the boat along, and the anti- lift catch engages on? Raising the cav plate above the transom surely would involve unbolting the engine from the transom & puting in packing pieces / drilling more holes to raise it?
No I was talking about raising the engine vertically up the transom which on larger engines is done by moving the transom bracket up a hole as they have about four holes to choose from.
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