Gumotex Seawave glued seam failure

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Kalif
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Gumotex Seawave glued seam failure

Post by Kalif »

Greetings All,

I haven't been on this forum for a while, but thought I'd drop in to share some of my experiences from a very eventful short trip yesterday.

A friend of mine in his Sea Eagle and I decided to go for a 'social distancing' paddle in Tomales bay. The weather was perfect, 61-65F, with just enough breeze. The water was cold as usual there, but there were some brave swimmers around. About 3 hrs. into our trip, just before we got to Marshalls beach, I felt a huge bump, just behind my seat on the starboard side. My first thought was a that a great white, huge sea lion or another large animal hit the kayak. I turned around, didn't see anything, so I headed for the shore (not slowly). As I was approaching the beach, the kayak was deflating on the right side and the bottom. Upon inspection, I realized that nothing hit the kayak, but what I felt was a great re-distribution of air inside and between the bottom and right chambers. Basically, a seam where the bottom and right chamber meet inside had come completely undone/unglued. There was also a small hole in front, on the outside of the hull, at the end of a glued seam where the two chambers meet.

I could not believe that after only 5 years of fairly light use, it would have such a catastrophic failure, that could compromise safety, had it happened in the middle of the bay. Without the bottom and one of the chambers, an inflatable kayak is not really seaworthy enough to make any progress under a paddle. I didn't know that the bottom and side chambers are actually one big tube that is glued inside to create apparently separate chambers. That's a big safety issue, as I experienced. What puzzles me most is that I do not over-inflate it and use it in not so hot areas with mostly cold water. I have owned many gumotex kayaks over time and have a lot of experience in inflatables and sailing, safety at sea, etc. I still think that Gumotex boats are fantastic, for a variety of reasons, but this was eye-opening in many ways, as one doesn't really expect a mayor failure of this sort to happen.

I wonder, if anybody has ever had similar experience, which I assume must be quite rare. The boat was purchased from boatpark in Czech rep. in 2015,before it was for sale stateside. I got a very good support from them and will try to reach out to see what they suggest. I don't know if it's beyond repair, as the issue itself is inside the tubes. Only a small hole that could be patched is visible from outside, but wouldn't solve the problem one bit. I believe INNOVA offers some sort of repair, so will have to get in touch with them too. It's way past warranty, but I hate to throw it away, if it can be repaired somehow.

I have followed a blog at inflatablekayaksandpackrafts.com and I'm familiar with the mods that make the whole boat withstand even higher pressure, so what happened yesterday, just doesn't make sense to me. Sure, after five years of folding and unfolding, the seams/glue/etc. may become weak (it's the seams that are a weak point, unless it's been vulcanized), but I've owned so many of older Gumos, that were much older and nothing ever remotely similar happened.

If anyone has any thoughts, suggestions, experiences that are at least similar, please chime in, if you have a moment. Or if you have any idea how to go about the repair.

Thanks and happy (and safe) paddling

Photos:

https://photos.app.goo.gl/qxgRNpAVmCWJ75gN8
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ChrisvonS
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Re: Gumotex Seawave glued seam failure

Post by ChrisvonS »

Sorry to hear of your Seawave disaster. That would be quite unnerving alone at sea.
Before I finished reading your post I assumed you'd left it out in the sun, as happened to my 2-day old Feathercraft Java once (lesson learned!).
But clearly you are an experienced IK owner and the conditions on that day at least, were not scorching.

I have heard of it happening before.
A Greek SW owner had the side blow on a hot beach (despite reducing pressures) but managed to get it repaired and then fitted side PRVs as I did.
See his comments here:
https://inflatablekayaksandpackrafts.co ... x-seawave/
I don't recall him explaining the floor/side blew into eachother.
I didn't know that the bottom and side chambers are actually one big tube that is glued inside to create apparently separate chambers.
This would be news to me too, though I don't know exactly how these boats are assembled.
There is definitely a seam floor-to-side so it's not all one piece, internally glued.

In the graphic below I wonder if SWs are assembled as left – not so good and hard to beleive in engineering/safety terms.
(The sandwiching could be switched: side-wrapped-by-floor, but you'd think PRV-protected floor-into-side - as shown – is safer.)
Or as right, so that should a floor or side seam separate, the other chamber is not affected.

Image

I sawed an irrepairable old Semperit IK in half once to see how the I-beams were made.
(https://inflatablekayaksandpackrafts.co ... k-autopsy/)
But I didn't look too closely at the sidetube/floor join.
Below is the best photo I took, but doesn't really help.
Looks like a single piece of fabric, floor-to-side, with a very thin glued seam (this was a low psi boat).
Image

Do you think the leak (slit) happened with the bump or later?
I can see the sides/floor failing internally, but not enough to blow a hole out the side.
It's not like the side/floor pressure difference is huge.

Also, where it that slit? Looks familiar. Somewhere up front?
I've looked at my 100s of SW photos but can't see it to get a context.

I wonder if cumulative over-heating of the sides over the years slowly weakened the seams?
Or the boat was glued up on a Monday morning after a big fat Czech wedding ;-(

I think you should contact Gumotex in CZ to ask what may have happened.
They may no help but i think any IK manufacturer would want to be aware of failures and their circumstances.

I suppose a repair would require ungluing the seams with a strong solvent like MEK, then carefully regluing.
A good RIB shop ought to be able to do that.
Or maybe theboatpeople.com down in Danville. Not far from you?


btw, does anyone know what has happened to Innova website?
It's been like this for months.
"We are sorry. This website is in the maintenance mode. Please come back later."
[maybe they only do FB now?]
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Kalif
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Re: Gumotex Seawave glued seam failure

Post by Kalif »

Hi Chris,
Thank you for your helpful reply. I have followed your very website for a while now. All very good stuff.

It could be that the seam between the chambers looks like the left side of the sketch you made. Definitely not like what the right side of the sketch shows, as the chambers are now connected inside. It could be how the bottom and the sides are glued, but thinking that the higher pressure is in the sides, it is possible be that the red part goes inside the blue-colored bottom, given what it felt like when it happened.

Here are some answers:

Do you think the leak (slit) happened with the bump or later?


I was about 200 yards or less from the beach and after the bump, which I later understood to be the pressure equalizing between the bottom and side chambers, it started deflating slowly. By the time I reached the shore (a few minutes) it almost fully deflated through that slit. So, I would guess that it all happened at the same time. There are no obstacles in the water there and it wasn't an animal hitting the boat, as I didn't see anything. It sure felt like it though.

Also, where it that slit? Looks familiar. Somewhere up front?
I've looked at my 100s of SW photos but can't see it to get a context.


It is about 1 or 2 feet back from the tip of the bow on the bottom of the right (starboard) side. It is not a hole, but the end of the glued seam where the side chamber meets the bottom (that's the place where round side chamber becomes narrower and goes into that vertically-slabbed shape to form the pointy bow). It looks like the end of that seam just came undone due to pressure. I'll try to get some better pics of that. Basically, the kayak is fully intact, barring that small seam. If I could put some temporary tape on it, I could basically inflate it and take more pics. However, when deflated, I was able to feel that the side chamber and the first rib of the bottom have now become one chamber for the length of about 5 ft, inside the bottom of the boat. Those 5ft run from the slit, which is near the bow, all the way back to roughly behind the center seat. Behind that, all seems to be fine towards the stern.
The problem is that in order to repair it, one would need to open the chamber completely on the top seam, creating more damage than there currently is. The real damage is inside, but I hate to throw away the whole thing, if there is a way to fix it.
So far, I have only written to boatpak, but received no response. I'll send a full description to Gumotex too, but would prefer to find someone locally in the US to fix it. I'll contact The Boatpeople to see what they think. They have a very good write-up on various materials used in IKs.

The issue is if one needs a factory-size tools for gluing all that together or whether it is within the DIY domain. The seam is 5 ft. long, after all, and all inside the boat, without the access to it. What do you think?

I wonder if cumulative over-heating of the sides over the years slowly weakened the seams?

I was thinking the same, but I don't really use it in extreme heat and I only inflate it so it is firm enough not to sag in the middle. I stopped using the gauge I got from boatpark with the boat, as it is inaccurate, in the wrong direction. It doesn't show the right pressure. If I inflate the bottom until the PRV kicks in and than measure it with the gauge, it shows just a fraction of 0.2b, which makes no sense. I usually go by touch, making sure it's not over-inflated. I know it's not the best method, but looks like you've been running much higher pressure, with no issues.

I'll have to do more inspecting of it and post more pics soon.
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ChrisvonS
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Re: Gumotex Seawave glued seam failure

Post by ChrisvonS »

So the side tube is glued to itself and the flap-seam covered by the edges of the floor.
Now we know. If it's all well bonded at the factory I can't see there being that much difference which way it's done.

I wonder if your boat got poor bonding. Badly mixed glue/went off/who knows.
It does sound as if you've been as careful to avoid over-pressure.
For years I never owned a manometer, I just footpumped my Sunny until the floor PRV hissed, then inflated the sides to 'feel' the same.
If anything, it was always on the side of caution.
Now I know Gumboat sides can handle more.

When the side/floor seam popped maybe the mild explosion caused the outer slit to blow.
I would pump up the good side tube and see if you can spot the floor join seam separating anywhere.
If you can, boat may be a write-off.

I am sure Lee at BP will have ideas.
Either you dissolve the seam bond and reglue – there must be a solvent/technique for that which won't disssolve the Nitrilon too.
Or you need to perform open kayak surgery and make a long incision in the side tube to clean and glue the failed seam from the inside.
Then put a long strip patch – say 4 inches wide – over your access incision. (Easy to buy hypalon offcuts on ebay I find).
Having worked with two-part hypalon glue, I can tell you that stuff sticks for good. See autopsy link. Get a tyre roller tool.

Knowing what I know now about proper gluing, I might risk DIY had I the space.
Otherwise, get a RIB shop or BP to do it.
It's definitely a boat worth saving, assuming outsourced repair is economical.

I sold mine early summer and really miss it (and having an IK in general).
Luckily the mate to whom I gave away my (I thought worthless) Sunny in 2011 has offered to give it back as kids are gone and it's long unused.
A 20-year-old Sunny went on eBay yesterday for £325!
People here are gagging for IKs and prices have shot up due to poor post-lockdown supply, staycations and a good summer, I'd guess.

To paraphrase Robert Redford: 'All is [not] Lost! ;-)
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ChrisvonS
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Re: Gumotex Seawave glued seam failure

Post by ChrisvonS »

Have a look at this post on the main French IK forum from 2018.
https://www.forum-kayak.fr/index.php/topic,11988.0.html

Looks like an identical blown seam and chamber co-joining.
While on land drying, luckily.
His boat was a 2015 so also well out of warranty.

"What worries me is that after the explosion of the sausage, the bottom also deflated. I have the impression that the weld between the bottom and the flange has come off over the entire length of the boat.
I still have nightmares in which I wake up to the sound of the "detonation
" ...

"And there I really have to take my hat off because Gumotex simply made the decision to replace my kayak with a new one."

Fyi: replacement may have been helped by the fact that the French Gumotex importers have an unusually good reputation, are into their Gumboats and have a close connection (including design input) with Gum in CZ.
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Re: Gumotex Seawave glued seam failure [added]

Post by ChrisvonS »

ChrisvonS wrote:
Tue Aug 11, 2020 5:08 am
So the side tube is glued to itself and the flap-seam covered by the edges of the floor.
Now we know. If it's all well bonded at the factory I can't see there being that much difference which way it's done.

[Added: actually I've since learned that the inner-surface (uncoated natural rubber? 'neoprene'?) to inner-surface bond is chemical not glue, and stronger than glue. So it makes sense to seal the side tube seams like this - inner to inner - as they can get more stress: hot and taught, even on the water and have no stock PRVs. The floor is always protected by the PRV]

I wonder if your boat got poor bonding. Badly mixed glue/went off/who knows.
It does sound as if you've been as careful to avoid over-pressure.
For years I never owned a manometer, I just footpumped my Sunny until the floor PRV hissed, then inflated the sides to 'feel' the same.
If anything, it was always on the side of caution.
Now I know Gumboat sides can handle more.

When the side/floor seam popped maybe the mild explosion caused the outer slit to blow.
I would pump up the good side tube and see if you can spot the floor join seam separating anywhere.
If you can, boat may be a write-off.

I am sure Lee at BP will have ideas.
Either you dissolve the seam bond and reglue – there must be a solvent/technique for that which won't disssolve the Nitrilon too.
Or you need to perform open kayak surgery and make a long incision in the side tube to clean and glue the failed seam from the inside.
Then put a long strip patch – say 4 inches wide – over your access incision. (Easy to buy hypalon offcuts on ebay I find).
Having worked with two-part hypalon glue, I can tell you that stuff sticks for good. See autopsy link. Get a tyre roller tool.

Knowing what I know now about proper gluing, I might risk DIY had I the space.
Otherwise, get a RIB shop or BP to do it.
It's definitely a boat worth saving, assuming outsourced repair is economical.

I sold mine early summer and really miss it (and having an IK in general).
Luckily the mate to whom I gave away my (I thought worthless) Sunny in 2011 has offered to give it back as kids are gone and it's long unused.
A 20-year-old Sunny went on eBay yesterday for £325!
People here are gagging for IKs and prices have shot up due to poor post-lockdown supply, staycations and a good summer, I'd guess.

To paraphrase Robert Redford: 'All is [not] Lost! ;-)
inflatablekayaksandpackrafts.com

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