Zodiac 340 losing air at sea...

[Max...]

Very strange.

Fastroller 340 owned it a few years now, still in mint condition. But for the first time today after 30 mins light chop maybe F3 noticed starboard and front tube deflating slowly but enough to force us back. Pumped it up but once out again after more wave hopping same thing. Ended up pretty soft.

Baffle may be leaking internally so not sure which tube/valve is faulty. However, we then left it on the beach and it seemed fine maybe very slight loss, bouncing at sea seems to be effecting the issue.

Back home I've smothered soapy water all over, no sign of any damage or leaks from the valves or tubes.

Help!

[Locozodiac]

If keeps deflating, should have a well hidden air leak, could be around floor fabric where joins against tubes ? On the market can find a product that's poored inside air valves and seals all air leaks, works well...

Happy Boating

[Max...]

Update, floor out, in the garage, slighty over-pumped up to 4 psi, leak detector sprayed all over the seams etc, bounced up and down on the tubes and still no obvious leak. A *minute* sign of a bubble by one seam but less gas escaping than a gnat's fart...

Any ideas...?

[S4Simon]

Okay an overview of Zodiac leaks in general. For a boat to lose pressure within an hour the hole would have to be the size of a fish hook puncture This type of hole would not produce any bubbles during a soapy leak test as the air is pushing out too fast. It would produce a large audible hissing sound and the craft would lose pressure within the hour. If you've found some small hole where bubbles appear over a couple of minutes this would cause the craft to defalte over 3-4 hours. With regard to valves on the Zodiac 340 the craft has two valves as such. The main screw in valve and the top screw on cover. The main valve will always leak at a fast rate - that's just what they do. The top screw on cover is designed to create the airtight seal. In your case I would expect that this top cover was not on tight and thus you lost pressure pretty quickly. And because the baffle inbetween the two tubes is curved, losing pressure in one will cause a slight deflation in the second. As you mentioned that when you got back onland and pumped back up with no signs of a major leak, I would suggest that the top screw on cap to the valve was not on properly in the first instance. Nothing really to stress about. :-)

[Max...]

Hi Simon, thanks for the post. I'm familiar with the Zodiac valves and have changed them before - no issues there - as you say the inner valves generally leak a small amount and the outer cap is the main seal - these were all fitted 100% properly and not leaking.


Obviously I double checked this after the first time out yesterday but as per post above the same thing happened second time out.

I've got an accurate guage, details here:

http://www.rib.net/forum/f50/adaptin...sib-42375.html

I've had my ear all round it in a silent garage yesterday to listen for hissing and absolutely nothing.

As a comparison the keel has a small leak (always has - you can hear it and see it bubbling) but even with the obvious leaking if I pump that up to say 3.5 psi it will still be 3 psi two days later.

This morning (having left it for 12 hours with just under 4 psi all round the three chambers are still showing a little less (3.75 psi or so) but all consistently including the port tube so I put that down to changes in atmospheric pressure or just the slight loss through the valves. After 30 mins at sea the starboard tube yesterday would have been down to 1.5 psi...

[S4Simon]

I'd next check for leaks where the airfloor hits the tubes. ie keep the floor deflated and apply the soapy solution in that inner lower area.

Next question is. What order Do you pump up - Port, bow and then starboard. If this is the case then a deflation in the starboard will cause a slight loss of pressure in the bow. Which means you can focus just on the starboard tube.

[Max...]

Floor is completely out - I've checked *so* carefully along all seams, floor tubes - really nothing to see, no leaks - used proper leak detector spray as well as a very close ear. Nothing!! Only thing I can think of is the flexing at sea is opening something up but I cannot recreate it...

Boat stays inflated for storage and transport all the time I don't pack it away.

[frankc]

Is the floor and keel connected by a tube so that both are filled with air through the same valve? My dealer had one in for repairs and told me he had seen problems where the tube connects to the floor or keel.

[Fenlander]

No Frank Max's boat is the type with a normal low pressure sausage keel under the air floor. The keel has its own valve.

This is a puzzle Max and despite trying to think it through there is nothing that comes easily to mind. I thought valves I have to admit like Simon as those in that era of Zoadiac will easily let down if the outer seal isn't perfect. I'm thinking the valve suround is rigid where the cap seats so no amount of flexing would lose pressure there.

I don't suppose anyone is pressing on a valve in bumpy conditions? Clutching at straws really with that.

How about flexing the boat while under a garage test. Support it front and rear and carefully apply your weight (or a child) in the middle. Turn it upside down and do the same.

Remind me of the chamber arrangement. Is it main tubes x2 and bow as the 3rd?

[S4Simon]

Well obviously here's an excuse to take it out for a run again. This time inflate the starboard tube last, so that if that tube does start to deflate it will not affect the bow.

I've never seen a hole fix itself on a Zodiac so I still believe it comes down to that starboard valve cap causing a one off issue.

And yes 2 mains and a front bow valve.

[Max...]

Thanks chaps, appreciate the input.

David - yes, valves to port, starboard and bow.

Its still up at pretty much the same pressure now for 16 hrs so it is odd. I'm out again Saturday so will see then and be sure to take the pump with me, as you all know the effort in getting everything ready and going out (dragging the family ) means the last thing you want is issues on the water.

I've checked all the outer valve rubber seals - all good and in perfect working order. Trying to manually 'flex' or distort the valve housing causes no leaks.

[Max...]

Oh well, a final 'pressure' update - down maybe 0.25 psi or less all round now another day on so it cannot be a tube hole, will see how it goes at the weekend and I'll carry the pump on the boat this time like I used to...

[S4Simon]

You won't have any issues.

Now that your taking the backup pump. :-)

The boat knows your moves.

[Max...]

Took the backup pump Saturday, 25 NM round to Beachy Head, some kneeboarding and playing in the waves later when the wind was up and yes it was perfect, no issues. Last time out must have been the valve cap loosened or similar. One cap is quite easy to turn compared to the others but kept an eye on it and all was well. Hit 17.9 kts too 1.5 up, you gotta love that little Tohatsu. 9.8.

[whisper]

Is it the warm air in the tubes cooling down when in the water?

[Max...]

No, when this happened in the OP it was much more significant than that, all OK now though.

[Fenlander]

Glad it was a nil cost "repair" Max. Such things are still worrying though while you try and get your head round what could possibly be the cause..