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Old 22 September 2006, 19:35   #11
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Quote:
Originally Posted by Nasher
The plan is to purchase a bare hull and tubes, probably with a small cabin, around 7.5 - 8.5M then build it up myself. Including putting the engine in.

I'm looking to put an inboard diesel in around 300HP and hoping to keep it to around 1.5 to 2l a mile at cruising speed. - Go on, tell me its not possible.
Nasher, if you can push it, go for 9.5mtr.

I'm getting a little better than 1 mpl. and that's over a period of 1500lts of fuel. That's 8.5mtr and more than 3 tons with some fuel and crew.

Here are a few pics of drives and transom shields. They may give you something to work on. The Bravo looks to be just about level with the hull bottom but none of the Volvo drives are. There is somthing else I might mention re outdrive v outboards. There is a limited angle of trim above which you can't run the engine. It's determined by the angle the U/J's bend through. For the Volvo, and I'd guess for other drives too, there is also a lesser angle where the engine can be running but only at limited revs for the same reason. That angle isn't particularly high.
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Old 22 September 2006, 19:59   #12
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Call me ignorant here someone but what hull profile would you need to mount the intake for a jet drive? I've never actually seen a jetboat intact and out of water where I could look that closely.
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Old 23 September 2006, 12:46   #13
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JW

Thanks for the images, I've downloaded them to study later.

Nos4r2

Good question, I'd also be interested to see.

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Old 23 September 2006, 16:25   #14
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Originally Posted by Pete7
is it though ? how do OD and VTs Ribs manage? hence the desire to take one for a test drive, or even a trip in Pressmans Carson
the second time we saw O/S she was parked in the middle of a tarmaced public road without a trailer, thankfully the stern drive lifts clear enough to park her on dry land.

Pete
Pete you are most welcome, the boat is in the marina at Hythe so whenever really it may dispel some of the negative comments
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Old 23 September 2006, 16:30   #15
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Call me ignorant here someone but what hull profile would you need to mount the intake for a jet drive? I've never actually seen a jetboat intact and out of water where I could look that closely.
These are the best i have!!
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Old 23 September 2006, 18:19   #16
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Quote:
Originally Posted by pressman
These are the best i have!!
Holy cr4p what is that beast of a thing?! Got any more pictures? I just made a sex wee!

-EDIT- Just did a search for more pictures, double sex wee! Amazing machine my good man, maybe if I win the lotto....
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Old 24 September 2006, 03:50   #17
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Originally Posted by pressman
These are the best i have!!
That boat is pure sex


So, based on what I can see(and pure conjecture):-

If you want a single jet you'd need a flat on the keel towards the stern (like a planing pad) to mount the intake-or twin jets a la Pressman?

I'm guessing but twin jets like that should suck downwards less than a single jet with the same output due to being mounted at an angle?

Would splitting the intake of a single jet to either side of a deep V hull mean a noticeable decrease in efficiency and would it be feasable to do this and still keep the impeller below the waterline?? Obviously it'd cause some loss of power- everything's more efficient if it only goes in a straight line...

I'm assuming you have to have the impeller below the waterline at rest to at least some degree to get it to pick up water properly?

Am I making sense?
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