Inflatable Kayaks Dropstitch

colbysmith

colbysmith

Active member
My inflatable Hobie has developed a bubble, and I'm not sure why. I have also discussed this some on the Hobie forum, and one response said it may have something to do with the drop stitch. Not sure I understand exactly how it all works, but trying to figure out if the bubble is an issue that a air leak could form from, or if it's just cosmetic. Anyone more educated about this? Colby

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the inflatable floor (high pressure) drop stitch, is hundreds of strings which tie the top and bottom surfaces (re-inforced) of the hull or floor. If these threads break, there will be a bulge. Not sure that is what you have. I know that Hobie can recondition their boats. I sent my single sit inside back for repair under warrantee.

I would call/email the Hobie factory and see what they say-

worry is what is going on underneath.
 
Hi Bob. I did email Hobie, but really didn't get much of a reply.

Thanks for reaching out to Hobie regarding your Mirage i11s. From what I can determine, the air bubble looks cosmetic and may not impact the structural integrity of the boat. I am unsure how this occurred, although we would recommend to ensure you're storing your i11 out of the sun, heat, humidity and at least partially deflated. Hobie offers a self repair step-by-step guide for Hobie Inflatables, and here is the step-by-step guide below, as well as the recommended materials for this process. Here is a link to the video outlining a patch process in case it is helpful: https://www.youtube.com/watch?v=vmjdyhu_sVc
Click to expand...

The youtube video has nothing to do with repairing this bubble, but rather how to patch a leak...

I have gotten a little bit more information from the Hobie forum, but not much. It is well out of warranty now, and they no longer manufacture this model. I'm still doing some research but at this point don't think the bubble is growing. Colby
 
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.
 
This may be a little extreme, but you can put some HH66 glue with a syringe into the bubble, then press it down--you will probably have to put a small patch over the entrance of the needle or hollow structure you use to convey the glue.

The other option is to send the boat back to Hobie and get it repaired. I did that with my. sit in 9' Hobie and they basically with thru the boat, fixed and upgraded it. (IF anyone is interested in a 9' sit in--it has only been used a few times and I need to "move it". Really good deal for someone.
 
This may be a little extreme, but you can put some HH66 glue with a syringe into the bubble, then press it down--you will probably have to put a small patch over the entrance of the needle or hollow structure you use to convey the glue.

The other option is to send the boat back to Hobie and get it repaired. I did that with my. sit in 9' Hobie and they basically with thru the boat, fixed and upgraded it. (IF anyone is interested in a 9' sit in--it has only been used a few times and I need to "move it". Really good deal for someone.
Click to expand...

Thanks for the suggestion Bob. The syringe and HH66 might be worth doing. I just wonder if it would work with whatever is currently in there that feels tacky. I have written Hobie again with pretty much the same information as what I wrote above. So far I'm not over impressed with their customer service. To often they more or less refer me back to the seller. (Maybe I should call the marine shop that I purchased it from, but I don't think Kayaks are their primary business. They just happened to have a few on the side, but I don't think they service or are knowledgable about them. Maybe I'm wrong.) Perhaps tomorrow I'll try calling the dealer, and if no help there, I'll try calling Hobie. Email doesn't seem to work well with them. Colby
 
Interesting reply from Hobie tech. I'll bet they have seen this before. I am not surprised that this is the outer layer only. I don't know how the drop stitch are attached, but they may pass thru a layer, which is then attached to the "outside layer" My guess is this can spread--but you have it marked.

From their answer we can assume that you cannot leave the boat inflated in the sun--but that you have to let some pressure out if it is sunny or hot, after you use the boat, and then add pressure when you are ready to use it. If that is the case, then it makes the boat difficult to use as a dinghy.

Based on what they say--I would agree that it would be best to cut his open, fine the pinhole (?) and repair it--then you can spread the glue and put the top deck back on. You have to have some hard object to allow rolling the repair upper layer. HH66 is a contact type of cement, so if done properly you don't have to clamp it. I just used a wooden roller when I made the camper "canvas" enclosure for the back of the 25. Two part glues may be stronger, but when I did "destructive testing" the fabric pulled apart before the glue line failed. After you have sealed the bulged layer, you may want to put some PVC fabric over the incision.
 
I have a Bote kayak. It has similar bubbles on the sides where a D-ring patch is attached to the surface. I really don't think anything of it.
 
I wasn't overly concerned with the bubble. Until I read the other persons post. My bubble is very close to the plastic rim where the peddle (Mirage) drive is placed. If that seam there was to let go, I would lose air pressure in the main body. Not what I'd want to happen while kayaking away from shore in deeper water! So at this point I'm a little leary about using the kayak in colder water away from shore. It'll be interesting to see what the next reply from my dealer or Hobie is. These Kayaks aren't cheap, and if Hobie isn't going to stand behind their product, you can bet I'll be honest with others about that fact, and will likely replace this Kayak with another Sea Eagle Kayak like my wife has. Or perhaps switch to more of a dinghy like the Kaboats. Colby
 
Not really sure where to go with this reply, other than to say I guess Hobie feels 5 years is a normal life span for the I11S Mirage Kayak used recreationally... Colby

Inflatables are susceptible to heat and over-pressurization... and heat causes over-pressurization too. Inflatable products using glues are subject to glue degradation and failure from age and heat. This is an issue across the board with other companies. There are restrictions on better (but toxic) glues (EPA) I believe and this can limit the choices companies can use. Our product is unique in that we also have a well that the materials have to bond to. No mechanical connection should be required.

Unlike rotomolded and thermoformed products, inflatables can degrade just sitting in storage as the glue materials age and succumb to heat. 5 years depending on conditions and level of use is actually pretty good. I have been to the Caribbean and seen mountains of inflatables that have failed in use by charter companies.

Inflatables offer many advantages in weight, storage, and transport space required... but they do have limitations in lifespan. One of the reasons the warranty on inflatables is less than on other products.

We don't do repairs here at our facility, but there are companies that do in many areas of the country. I would contact those kinds of people (if your dealer is not able to help) for the best help in handling a repair.

_________________
Matt Miller
Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
 
There have been inflatables which have lasted a long time. For example I had an Avon RIB and it was over 20 years old, and still in good serviceable condition when I sold it--no patches, no busted seams, but some fade in the outer Hypalon skin.

My son buys a 10' Costco dinghy every 6 years for running around Dana Point harbor. , and has an older Avon he uses for serious work.

The good Achilles also lasted many years.

When Zodiac started buying up other companies and went to PVC, there was a marked decline in longevity.
 
There have been inflatables which have lasted a long time. For example I had an Avon RIB and it was over 20 years old, and still in good serviceable condition when I sold it--no patches, no busted seams, but some fade in the outer Hypalon skin.

My son buys a 10' Costco dinghy every 6 years for running around Dana Point harbor. , and has an older Avon he uses for serious work.

The good Achilles also lasted many years.

When Zodiac started buying up other companies and went to PVC, there was a marked decline in longevity.
 
I have to laugh at the continuing discussion on the Hobie Forum. The "Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA" last post says he was just giving his two cents, that he's not really an inflatable guy... Colby
 
Well I finally got the nerve up to cut the surface bubble that would form on my Hobie Kayak when I inflated it. I cut an H in the bubble, put a lot of the H66 glue in there, and then placed a patch over that. So far it looks to be holding, and no bubble. The top layer is just a laminate over the inner layer that holds the dropstitch. I couldn't really tell where the leak was at in there, and I suspect it may be close to where the center black plastic piece is that the peddle drive mounts in. Colby


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I will never recommend Hobie's inflatable Kayaks again. They will not stand behind their product, and even go so far as to state that getting a couple years of use out of their Itrek 11s is actually pretty good. Reading the Hobie blog it appears others have also had the same delamination issue around the drive hole. One guy stated that unfortunately the Hobie Mirage Drive inflatable is more or less a disposable unit, sadly not long lasting. Hobie offers no repair service or recommendations for repair. I love the Mirage drive and may end up going with a Hobie Hard Shell kayak, which seem to be made better. Still overpriced however.... And, apparently their newer inflatable kayaks weigh a little less, as they use material 1/2 as thick as their older kayaks! I sent an email asking of their new kayaks will last any longer, and they've failed to reply. That lack of a reply speaks volumes!

The bad mood came from getting the Hobie out for this months first trip of the season, and finding another large bubble. This time on top and bottom so I'm assuming it is failure of the drop stitch. I no longer trust this kayak in deep, cold waters. It's basically become a pool toy!

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This is the top side.

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This is the bottom side.

Colby
 
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