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Old 22 April 2011, 18:06   #1
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first trip of the year!

Hi all,
First trip of the year today with my new outboard.

Setup is a 3.2m airdeck with a 9.9hp 2 stroke.

At full speed the boat sort of buckles/bends in the middle, and then after a while straightens out again.
Could this be that the air floor isn't inflated fully? Any suggestions please.

Also again when flat out every now and then water comes over the transom into the boat.
Is this just part of the fun of sibbing or is this a curable issue?

Thanks.
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Old 22 April 2011, 18:33   #2
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There was a suggestion on here that Prowaves were prone to this but I doubt it.

Check that your pressures are right. You need a gauge! Deck/keel pressures can be quite high, if you don't have them at the recommended pressure, it won't work - end of.

Water over the transom shouldn't be an issue, unless you're throwing shapes. It might be an engine trim issue or loading.

Check the pressure and trim and see how it goes...


I'm getting mine in the water tomorrow, first time this season - looking forward to it
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Old 22 April 2011, 19:47   #3
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Quote:
Originally Posted by lockieboi View Post
.


again when flat out every now and then water comes over the transom into the boat.
Is this just part of the fun of sibbing or is this a curable issue?
sooner or later your going to get your arse wet in just about any sort of inflatable
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Old 22 April 2011, 20:46   #4
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Hi Mate,
I had the water over the transom issue when I first used my Zodiac. I was a little new to things then and tried running it with the beaching wheels in the up position. That worked!!
The warping issue is definitely pressure related. If you're using an electric pump, some of them cut off early when the pressure in the valve hits the "correct" amount of Bars, even though the tubes may not be. Try a foot pump with a decent gauge and see what you get.
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Old 22 April 2011, 21:38   #5
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Thanks for the replies.

I will try the wheels as I did have them at 45 degrees.

Can anyone recommend a pressure gauge? I have a foot pump already but it doesn't have a gauge.

Thanks.
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Old 25 April 2011, 09:49   #6
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Took the boat out again yesterday and by pumping it up a bit harder stopped the bending in the middle.

I folded the wheels into the up position but I am still get water over the transom when flat out.

Can anyone help with this? Could it be that the outboard is to low/high? (It is a short shaft.)

Thanks.
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Old 25 April 2011, 11:11   #7
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I got mine opened up properly yesterday and ran it in a range of conditions. She sprays water up in a fan towards the inside of the cone ends. It sounds like your situation. It wouldn't bother me though.

Your engine shouldn't be too high.

Pressures on the QS are (from memory):
11psi in the airdeck
6.4psi in the keel
3.6psi in the toobs

It's as tight as a drum like this - way more than one would pump in without a gauge...
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Old 25 April 2011, 15:48   #8
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Nice looking boat I like how the wheels are mounted low, makes them stealthy.

As to the water over the stern, run it full out and let us know where it is spraying from. Do you also have anything mounted to the transom other than the wheels? IE: transducer for a depth sounder. Often the depth of outboard is just a hair too deep. Do you have trouble with cavitation aka prop blowout? Usually signifies the motor is too high, or trim is wrong.
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Old 25 April 2011, 19:24   #9
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When running it flat out water sprays back at the transom from both sides.
(hard to explain but sound right in my head.)

Nothing else on the transom just the wheels.

It doesnt bother me as such only the amont of water taken on board.
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Old 25 April 2011, 19:53   #10
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looks superb!!
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Old 25 April 2011, 20:25   #11
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Doel fins should stop that!! Distributes the water better

Peter ~ askboatsandoutboards4sale@sky.com ~ 07930 421007
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Old 25 April 2011, 20:37   #12
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It could be a trim issue, Dolefins could help too and for 20 quid not a pricey test.
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Old 25 April 2011, 20:41   #13
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Thanks.

I have got some hydrofoils i took of the outboard when i got it!!

Will put them back on!

How should the trim be setup? Or is it a trial and error sutuation?

Sorry for all the question. Bloody newbies!!
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Old 25 April 2011, 20:48   #14
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Quote:
Originally Posted by Bighag7 View Post
It could be a trim issue, Dolefins could help too and for 20 quid not a pricey test.
Except that he'll have to drill four holes in his cav plate...

My engine, on the other hand, came supplied with doel fins and holes, thanks to the previous owner. I must pop them on and see what happens. If the OP wants to hold off for two or three weeks (I have an Appointment in Scroatland this w/e) I'll report back before he resorts to the bench drill.

______________

Edit - oh wow - you too. Fair nuff - we'll both test 'em then so!
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Old 25 April 2011, 20:50   #15
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Hi Mate,
It's trial and error old fruit. Sometimes I have to change my trim depending on how many people I have onboard and I have Dolefins fitted.
Is the prop original? Some props cause peculiar vortexs that push the water in odd directions if they aren't specific to your engine.
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Old 27 April 2011, 12:28   #16
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Or muck about with the trim pin - changng the angle of the cav plate relative to the direction of travel can make all the difference, and it's a free test.

Just as a sanitry check, you don't have a longshaft engine on there?
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Old 27 April 2011, 12:55   #17
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You could try lifting the engine up a bit a common mod with the Aerotec I have as you get the same thing happing with water over the transom!
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