Funny you should say that Bern, I have a honwave 3.8 and guess what? The port side air floor leaks! Now I sourced a leak under the trim tab and after painstakingly pealing back the pvc revealed a cut, like a sharp blade had caught it but not properly penetrated it. Yippee I thought so I applied a line of adhesive the length of the cut (only 15-20mm) and left it to dry with the intention of giving it another key and gluing the flap back over. That done I inflated it up to 0.4bar and hurrah! BUT! After checking 2hrs later the blooming thing had lost pressure😢 Now I've lathered it in soapy and revealed more bubbles coming from where the air deck is overlapped and meets the sponson below where the forward tube section is. My dilemma...... it could well be travelling the length of the boat and taking the easy way out? Next step.... peel back the tape a little and re-glue then do the same at the stern and at least contain it? Shame you can't put anything to seal from within. It's not life threatening and takes ages to go so low as to spoil a days fun, because 5mins with the pump and we're off again..... it's just a pain.
I've seen others with the same problem....it's a bugger innit?