Strange air floor leak

[Tommy c]

I have an air vee floor and it's sprung a leak.
The starboard floor chamber is loosing all it's inflation within 15 mins BUT the leak is on the port side halfway from bow to stern on the inside where the side tube and floor meets.
It's where the joining tape starts and ends.
Can someone please help advise if and how to repair

[909]

I'd apply heat, peel back the seams. Clean 3 times, scuff, glue 3 times, apply heat again then re-apply the seams.

After the repair, ... if you want .... it would be a good idea to add an additional patch on top of the work you did extending at least another inch or so in each direction for added strength

[Tommy c]

So should I use a 2 part glue or the 1 part that is supplied with the repair kit?
What's baffled me is it's the starboard chamber leaking but from the port edge of the port tube/floor seam??

[Tommy c]

I emailed boatworld and they suggested using a product called stormsure pvc glue
Can anyone give any feedback on this product?
Thanks

[Fenlander]

Tommy this is an odd one.... and seemingly impossible... but it's happening.

Before any repair thoughts you need to work out how this is happening.

First off in your images... what is the location of your close up image? In the broader image there are fresh bubbles at the area between floor and tube just below the valve... is this the location of the close up? In that second image there are bubbles between the two floor sections... is it leaking there too or is that just foam?

When these boats are made by design they would construct two separate high pressure floor slabs and then with tape sections attach them inside and out down the centre line then again with tape glue the outer edges to the tubes and rear to the transom.

If the starboard tube is losing air yet the bubbles are appearing at the port side location below the valve there is only one way this could happen. The starboard floor slab must have developed a failure somewhere under the tape that joins it to the boat and the air is travelling to the point of least resistance... that join in the tape port side.

The problem here is those joining tapes are meant to seal against water and hold the boat together... but they way they were glued on never designed to hold the high floor pressure back.

So no point in sealing the exit point as you would still have a faulty starboard side floor panel which will no doubt cause the leak to appear at the next weakest point along the joining tape.

I can't remember was this SIB bought new or used?

I would appreciate a current or past owner of a similar air floor design just checking through my logic of how this leak is running through the construction but I can't think of any other way.

[Limecc]

Maybe a stupid suggestion here.
Would it be possible to put the tube under suction and get the leak to draw in some liquid latex or glue? Excess can be wiped away before it goes off.

[Mattster]

Originally Posted by Fenlander

If the starboard tube is losing air yet the bubbles are appearing at the port side location below the valve there is only one way this could happen. The starboard floor slab must have developed a failure somewhere under the tape that joins it to the boat and the air is travelling to the point of least resistance... that join in the tape port side.

Agree with this. The leak must be happening somewhere along the edge of the starboard floor panel and travelling in a void between the upper and lower joining tape, until finally exiting on the port side. Attending to the leak at the point of exit is pointless.

The problem is that the leak could be literally anywhere on the edge of the starboard panel, so finding it is going to be tough. I wonder if pumping it and then listening very closely and intently as you move your ear around the edge of the panel might be one way to start?

[Fenlander]

>>> Would it be possible to put the tube under suction and get the leak to draw in some liquid latex or glue?

Problem is the leak source seems to be at least 2m away from its exit point. As the leak is from a HP section the only chance of a reliable repair is to find and repair the actual point of failure... bit of a nightmare in truth.

[Tommy c]

So I blew it all up the other night to wash it down after a little sea trip.
The sib is transported to and from the water on the transom wheels.
The sib is inflated and deflated on a tarpaulin, wrapped up and then wrapped again in the tarp and left in the van.
After I blew up for its wash down I went in for my tea and when I came back the starboard floor panel was flat.
Re inflated and proceeded with a bucket of soapy water outside proved fruitless. Turned it over and bubbling quite bad from the point in the photo on the port edge.
As you pump the bubbles increase with every stroke.
The leak is on the port side where the joining tape from side tube attaches to the floor panel.
The joining tape does not overlap at its start and end point.
The close up is with the side tube deflated to gain a better access view.
This morning I re checked and the port floor panel has lost pressure and has a very minor bubbling leak at exactly the same point on the starboard tape.
Makes it even more mind boggling.
When I emailed boatworld there was no explanation just a suggestion to use the stormsure product.
The leak is coming from the crease in the joining tape, not the full width of the tape
Oh and yes, I bought it 2nd hand and was only used a handful of times from a guy who had sold up everything to live on a narrow boat and I do believe he is a genuine guy to the point where I can see his travels on FB and everything tallies in

[Fenlander]

So now it seems both air floor panels have failed?

I would double check that neither valve leaks so adding an element of false diagnosis. But if both floor panels have failed the hard truth is it’s either a huge amount of work to repair that may or may not see success.... or sadly it’s a scrapper.

My worry is if you can see the bubbles blow up at each pump stroke it sounds like a failed seam on the air floor not just some small problem. This massively increases the difficulty of any repair and the result would need to be spot on or not safe to go back on the water.

[The Gurnard]

Hi Tommyc ..just my thoughts for what they are worth .. so take it with a pinch of salt if you wish as I could be wrong.

I think I can clearly see damage to the tape in the close up photo of the bubbles. The stitches are burst and the PVC tape has in fact torn where the last two stitches were just before the tape join. I would lift the tapes at this point and hopefully you may find your leak behind the tapes here. The leak being caused by whatever burst the stitching and caused some stitches to rip the tape.



If both sides are loosing pressure..check the stitches in the same area on the opposite side..are they broken too ?

The bubbles coming out from the opposite side when you pump may simply be caused by the two air floor panels pushing against one another and having the same effect as an internal tube baffle. Example pump up one side ..and it presses against the other side which in turn pushes some air out its leak. Just a guess though.

[Fenlander]

That would be brilliant if that were the leak location so well worth a thought. To add to the stitch situation I remember a while back someone seeing these apparently missing and untidy stitches on a new Honwave of the same design. Answer was the tape is stitched together during the construction and glue process but then they cut all the stitches for the finished job.

[The Gurnard]

Ok..I was not aware the cut the stitches away Fenlander. I have not had a stitched SIB before so wouldn’t know. Its still worth lifting the tapes at this position ? because it it is air travelling along from somewhere else..I doubt its worth lifting everything to find out where its travelling from. If its there then its at least found..but could it give enough access to repair ? I imagine a high pressure floor will need a good overlap of a well glued patch.

[Fenlander]

It’s a real puzzle and the sort of thing you’d love to have in front of you to make sense of it.