Mirage i11s forming bubble in top of kayak

My Mirage i11s has a bubble that has formed on top just in front of the drive position. What would cause this, should I be concerned, and is there a way to repair it. The kayak holds air and doesn't appear to have any leaks. I would post a photo of the bubble, but not sure how to do that. TIA.

May be failed drop-stitch. There are hundreds of fibers linking the panels together. Without them... the boat would be a big ball.

https://suponthefly.com/drop-stitch/#:~:text=Drop%20Stitch%20construction%20is%20what,to%20make%20inflatable%20airplane%20wings.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Thanks Matt. I was concerned that it was sort of like a laminate, and that the inner piece had leaked into the outer piece. However, learning that about "Drop stitch", I'm sure that's what it is. Is there anything I can do to keep that bubble from getting any bigger, or will it likely stop wtihout growing any further? If I knew how to post a photo, I could post a photo of it. But the bubble is basically only about 6 or 7" in diameter, just in front of the drive unit mounting hole. Colby

No experience with this myself. I'll as Jacques to comment if possible.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

post a photo, so we can see what this is exactly - sure it's only cosmetic - wonder why this occurred - only thing I can imagine is it was left inflated - out in the heat - when you do that the pressure can rise tremendously and cause issues - always leave in shade while pumped - never leave it inflated over a long period - follow manual for care instructions. Only guessing - I have no idea what the damage is or what has caused without many more details and photos - work with your dealer locally for help.

I'm not sure where I can post photos here, so I'm using these from my C-Brats profile.

http://www.c-brats.com/albums/album3141/IMG_1436.jpg

http://www.c-brats.com/albums/album3141/IMG_1437.jpg

Looks like age related - heat - pressure... that is a failure of the drop stitching in that area... weird that only bubble on deck - should be also bulging on bottom as well in same area... there isn't a fix for this - just manage as-is. You didn't say how old it is - or where it's kept (location, & how it's stored... ) not left pumped up out the the sum long term

I'm guessing it's gotten hot and expanded.

I normally store it indoors (inside our house) and deflated. I do take it along on my boat for several days at a time, where it's left inflated. However I don't believe it's overinflated as I usually only inflate it to about 2.5 psi. I don't believe there is any bubble along the bottom. Just the top.

I almost missed this due to it not being posted in the inflatable section. Maybe the bubble is surface delamination from still connected drop stitching. Can you poke the bubble down and feel a harder surface? There may be a pinhole leak under but not including the upper skin.

Anyway regardless of the cause, how about pouring inflatable dinghy boat sealer into the valve? There have been accounts of using this successfully here; I guess you wrench open the valve and pour it in and rotate the hull all around to coat inside. Put valve back in, inflate, and maybe rotate some more.

Sounds messy, but the alternative of replacement may be challenging. My inflatable got the slow leaks and I haven't been able to source a replacement Hobie for years.

Did a little more researching, and closer inspection of my kayak today. I don't believe there is anything wrong with the drop stitch, as the bubble is only on the top. No bubble on the bottom. Also, I can press down on the bubble and feel more solid material under it. When I inflate the kayak, the bubble forms relatively slowly compared to the rest of the kayak inflation. Also, when I press down on the area, it sounds and feels like some tackiness between the bubble and the material beneath it. Somewhat like delamination where the inner and outer material was glued together. Not sure if I need to try to repair anything, or just leave it alone. I did mark the outer diameter of the bubble with a marker, so I can watch to see if it grows anymore. As for dumping some kind of sealer in the valve, I would assume that would make quite a mess every time I go to deflate the kayak.

Note to administrators, perhaps you can move this to the inflatable section for me. I'm new to the forum, and had a hard time figuring out how to make this post initially. Thanks.

Yikes, that sounds dangerous to this naive person. So if it is just what I suspected, the bubble lets go and your main chamber gets a slow but sure leak. I guess you still have side chambers, but your seat and pedals can lose all positional stability and you crumple up, maybe only limping home if you have a double ended paddle.

Do a search on this forum for toobseal; it doesn't stay liquid but with luck/skill makes a permanent inside seal. They are under different names, say from West Marine. It probably will gum up in the drop stitching, but maybe it starts thin enough to route it from the valve straight to the bubble area. Then replace valve and try to inflate before the stitching gets stuck and permanently prevents inflation (yikes - cure worse than the disease?).

UPDATE: maybe cut the bubble widely open and cover with water to find leak bubble. Then glue back together. No great solution comes to mind, but maybe helps to talk about possibilities...