Category Archives: Tech

Make Your Own Hypalon D-rings

See also:
Inflatable kayak glues and repairs
Repairing a Gumotex Seawave
MYO alternative to D-rings

You can get Chinese PVC D-rings dirt cheap on eBay but genuine hypalon D-rings (not PVC claiming to work on hypalon) cost a lot for what they are. Once you factor in the price of two-part glue, it adds up, especially if you have a few to fit.
It’s fairly easy to make your own D-rings for your IK to attach gear, thigh straps, footrest mounts and so on.

You can buy metal D-rings by the sack-load online, as well as round PVC or Hypalon patches. (‘Hypalon’ is pretty much the same synthetic rubber as Gumotex Nitrilon and Grabner Nordel). Or buy an off-cut (above right) for much less and cut your own. A D-ring doesn’t have to be round but it’s better if corners are rounded. You will notice how unusually hard it is to cut this stuff with scissors or a blade. The fibre core is tough: good for zero-elasticity in an IK.

Pictures below show how to make your own D-rings.
Go to this page for how to apply any patch, step-by-step.

Sticking to the Rules
I needed to fit some tube-top D-rings to properly support a second backrest in my Sunny 2020. I found a stray, opened tin of Bostik 2402 two-part in my kit bag, but with an expiry date of 2009. Back then I only owned this original Sunny and looking it up, 2402 turned out to be for rubber boats. Perhaps I bought it more recently but didn’t notice the expiry date. In the tin the glue was still liquid and unseparated, but the little bottle of Bostik D-10 hardener had long since evaporated. Digging around, I also found an opened bottle of PolyMarine hardener. Comparing chemicals showed they both contained Diphenylmethanediisocyanate, one of the few words that’s too long for a Scrabble board.
I mixed the wrong-brand hardener with the 11-year old glue 25: 1 and the bond looked as good as anything.

How to repair a ‘hypalon’ kayak

See also:
Inflatable kayak glues and repairs
Make Your Own D-rings
MYO alternative to D-rings


Hypalon is a cool-sounding word and although not made anymore, has become a generic term for the similarly durable synthetic rubber-coated fabrics still in production, like Nordel and Nitrilon. Once upon a time all rafts and were made of hypalon, then less expensive Asian PVC came on the scene. More about IK fabrics.


The other day, while lashing the Seawave to a chopped-down trolley, the bag sagged under its own weight and rubbed on the sharp edge of the hard plastic wheels which wore through the pack and then the boat’s hull (left) ;-((

The trolley had worked fine with my UDB drybag in New Zealand (below left), but that was partly because you can fully inflate a UDB via its one-way oral valve, transforming it  from saggy sack to firm travel sausage.

Ironically, just two days before I damaged my Seawave I’d snagged a BNWT Orlieb RS140 (right) on ebay.
I’d been eyeing up this non-rigid wheeler duffle for a while as a versatile Seawave transporter plus a reliable on-water drybag/buoyancy aid.
With a bag like this, an IK or whatever you got can be transported easily across any wheelable terrain, or carried as a holdall or on its backpack straps if you’re strong enough.

With enough practice applying D-rings, let along bike and moto punctures over the decades, I was confident I could do a bomb-proof repair on my Nitrilon Seawave. In a way, I was even a little chuffed that my 5-year old IK was earning its first battle scars. Plus, in my experience rubber-based IKs like Gumotex, NRS and Grabner glue more reliably than PVC boats. Shiny packraft TPU is even easier: you can just tape it, but packrafts are low-psi boats not normally inflated with mechanical pumps. My adapted Seawave side tubes run 4 or 5 psi.

Things you will need

The right two-part glue (below left)
Solvent (MEK, Toluene) and rag
Sandpaper or abrasive foam sanding block (note: Toluene eats foam plastic sanding blocks)
Masking tape
Small brush or wipe-stick
Tyre repair roller (right)
Well ventilated space to do a good job

STEP 1 • Match up a patch from your collection, ideally identical fabric. For a small hole extend the patch at least an inch.
STEP 2 • Clean the punctured area and patch surface with solvent and wipe dry. This time all I had was brake cleaner spray, but ordered some toluene for next time.
STEP 3 • Sand down the two surfaces and then clean and wipe again with solvent. Avoid touching these cleaned surfaces with your fingers.
Some colour coming off is a good sign you’ve removed any sheen or patina.
STEP 4 • Position the unglued patch and mask the perimeter with tape to avoid excess residue and to help with positioning. If the patch is not perfectly symmetrical (like above) mark it – but make it bold – I still got it wrong!
STEP 5 • Mix up some two-part Hypalon (Nitrilon; EDPM) glue. It’s rare than one-part glue works as well, but Aquaseal has worked for me, gluing a skeg-patch to a Grabner.
I found some mini brushlettes in my repair kit box – they must have come free with some glue.
STEP 6 • Brush on the glue thinly to the two surfaces. With Polymarine you then to wait 30 mins for it to cure/dry, then apply another coat and wait till touch dry (5-10 mins). Here’s their full guide:
You can see I made typical errors: mixed up too much glue (but better too much than not enough)…
… and applied too much glue on the patch…
… but a just-right thin later on the hull.
STEP 7 • With the deflated boat repair positioned on a firm surface like a hard floor or better still, draped over a wooden stool, carefully lay the glued patch over the damaged area…
… then – STEP 8 • peel off the masking tape and ROLL DOWN HARD moving from one edge to the other and again at 90° and again diagonally with your Baltic pine-handled roller, making sure the edges have stuck down. It won’t hurt to roll again in 20 minutes and again after an hour to make sure the two parts have well and truly bonded till death do them part. And actually, only about 25% of the glue was wasted.
In 12 hours the repair is cured and ought to last the life of the boat. Never do that trolley thing again!

Pumps for inflatable kayaks and packrafts

Inflation valves and PRVs are here


Your inflatable packboat needs a pump to get going and to top-up once on the water. These functions may be best performed by two different pumps. It seems the era of the bellows footpump (left) is over and even low-pressure IKs now come with barrel pumps.
A plastic-bodied barrel or stirrup pump is light but bulky so not something you’d want to tour with. They’re usually used for pumping up high volume/low pressure things like rafts, lots of IKs or kite wings. Some pump air on both up and down strokes to fill your boat more quickly but may automatically or manually switch to downstroke-only to attain higher pressures. They work best on flat, firm ground where you can stand on the stirrup plates and get stuck in. The Bravo 4 RED pump above is still only about £20 and will pump up an IK in 5 minutes.


I got a Bravo 6 with my Seawave once but found it hard work – who knows why. The cheaper Bravo 4 does claim to be an ‘R.E.D’ (‘reduced effort device’) and I can confirm this isn’t some gimmicky acronym. Like a Bravo foot pump, the other port on the Bravo’s handle can be used to deflate or suck air from an IK so it rolls up good and flat; you can see creases forming in the hull as you suck it down.

I left my Bravo 4 RED at home one time so bought a Sevylor RB2500G barrel pump (below left) for a tenner off ebay. Same size as the Bravo barrels, it well for the awkward topping-up of my Semperit’s lilo plugs. It came with push-fit, lilo-plug and bayonet adaptors and sucks as well as pumps. But pumping up my Seawave from flat was exhausting towards the end: I actually got out of breath and had to rest. Morale of this fascinating story: get a Bravo 4 RED and the right adaptor for your boat.

Not all barrels have a built-in pressure gauge which is obviously dead handy in getting the right pressure without needing to faff about using a separate manometer (see below). It’s worth an extra tenner to get a built-in gauge, especially with DS boats, or you can fit your own manometre: see bottom of the page.


The K-Pump Mini (above right) is a handy top-up pump or compact 600-g travel pump. It took 15 minutes to fully inflate up my Seawave; the push-fit nozzle works on any IK with one-way spring valves. You have to press the body of the pump against the valve. Using it a lot one time, I got the feeling it might break something or wear out the seal (which needs regreasing once in a while). I also now use the K-Pump to top up my Nomad S1 packraft which is too big and long to inflate firmly with just its airbag. Fuller review of the K-Pump Mini here. Hard to find in the UK, the long, and slim US-made K-Pump 200 (right) may also be suited to DS applications.

Left, the Bestway Air Hammer is an upside-down barrel pump which comes in three sizes and costs from just £6 on eBay. If you don’t want to paddle with your full-size barrel pump, the smallest Air Hammer could work as a compact top-up pump, like the K-Pump below but a tenth of the price.

High pressure pumps

More and more IKs now feature super-rigid, high-pressure drop-stitch hulls – either just floors or the entire hull which runs 2–5 times higher pressures than regular IKs. Your old Bravo footpump will blow its brains out trying to reach the typical 7-10psi.
Barrel pumps with slim and long bodies (as opposed to some of the shorter, stockier examples above) will put out less volume (D/S IKs have less volume anyway) but can attain higher pressures. You don’t need a super high-pressure iSup board pump. Some of these pumps may be double action, but at a certain psi will become single action to help gain higher pressures. I beleive the Bravo Alu 4 R.E.D (0.8 bar) works like that.
Whatever you get for your D/S IK, make sure it is rated to comfortably exceed your D/S boat’s pressure rating by say 50%.

Left: Bravo Alu RED <£20 • Middle: Bravo 110 >£40 • Right Itiwit (Decathlon) £20

Suited to low-pressure (non-dropstitch) IKs the once-popular Bravo bellows foot pump looks a bit crap, but lasted well, was fairly travel-compact and was easy to use without doing your back in. Occasionally the yellow tube split near either end if packed too tightly, so needed taping up (left) or cutting down and got shorter and shorter over the years. as mention, the bellows era seems to have passed.

Left: Kokopelli Nano pump: fold-out feet, screw-off handles, switch for one-way pumping as pressures increase, manometer in the handle.
Right: twice the volume Bravo Alu 4 with auto one-way switching (so it says). Bayonet valve fitting on the Nano keeps the valve open and so is for static manometer readings. With the push-fit adapter on the blue pump DIY manometer only reads as you pump and open the valve.
Both are better than soggy footpumps.

After many years a crease in the back of the bellows wore through, though that’s also easily fixed with duct tape. It’s a shame the Bravo pump is a tight squeeze into the Gumotex drybag’s outer pocket. If you use a Bravo footpump very frequently it just plain wears out, so if you’re using the car to get to the water get a barrel pump.


Pressure gauge (manometer)
Until I got a Grabner which has no PRVs but ran a relatively high, 0.3 bar (4.3 psi), I never bothered with a pressure gauge (manometer, left) and just pumped up by feel.
Since then I got a Gumotex Seawave and fitted PRVs to all chambers. That means I didn’t need a pressure gauge to get the right pressure, I simply kept pumping until each PRV hissed: the boat was then at operating pressure.
With high-pressure D/S IKs you probably do want a pressure gauge as the boat will perform best at the right pressure which may be higher than you’re used to.

Add a manometer dial to a plain barrel pump

I got myself a new Brave 4 Alu R.E.D barrel pump (left) rated to 0.8 bar (typical D/S pressure). It was under £20 without a gauge. The next similarly rated barrel with a gauge worked out at nearly fifty quid. That’s inflation for you.

Then I decided a gauge probably was a good idea in case my next IK doesn’t have full PRVs (quite likely; most don’t). I couldn’t find a way to fit my handheld manometer (as pictured far above) neatly, but on ebay saw manometer dials at various displays and with rear (behind) rather than bottom inlets for a fiver (right)
I chose one which displayed up to 1 bar / 14.5psi. Whatever boat I get next, D/S or otherwise, it won’t be higher than that, and anyway the Alu 4 is only rated to 11.6psi (0.8 bar).
The easiest place to drill the hole is into the hard plastic end of the hose by the handle (below). The brass thread will screw into the plastic hole easily enough, but a dab of glue does no harm. Now, finally I can measure as I pump.

Alternative to D-rings for IKs


Michael S from BC came up with a good idea for securing stuff, seats or thigh straps to the floor of your IK without resorting to gluing on expensive D-rings – something that takes application and the right glue to do well.
He suggests the cavity formed between the floor and the sides when you pump an IK up can be used to jam in short tubes attached to tape loops. Example left is a Sea Eagle DS, but I know the Gumotei and other IKs I’ve owned form a similar space along the sides.


Pictured below are some Sherpak Quick Loop tie-downs which go from less than $10 a pair on amazon US. You can buy Thule ones too for six times as much. The idea is you shut them in under your car’s bonnet, tailgate or doors (right) to help lash on stuff including boats.

But they could also be lodged in an IK’s floor/side cavities as you pump up, and of course can be positioned anywhere and slid forward or back.


It’s possible the 1-inch diametre tubes shown may be too big, so make your own using smaller conduit from a hardware store, or just a shore-side stick and washed up rope.
Neato mosquito as my Kiwi mate used to say.

Inflatable Kakak autopsy

Semperit main page

Performing my cutting-a-kayak-in-half trick gave me a long overdue chance to see exactly how they’re put together, as well as other stuff, like why it was failing and how well certain glues stuck.

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hypalon fabric

The neoprene inside
I used to assume it was the same coloured coating inside the boat as out; it’s just simpler. But of course, the diagram left is clear: what’s outside and what’s inside an IK hull is not the same stuff. There’s no need to waste UV-resistant hypalon coating (or colouring or that matter) inside the boat’s benighted chambers. All it needs to be is the same durable and airtight coating, and neoprene – the brown rubber-like coating left – does that fine.
I bet I’m not the only one to mistake ‘neoprene‘ as simply that closed-cell sponge used in wetsuits or laptop sleeves. In its solid form it’s a durable synthetic rubber, but I presume lacks the full-on UV resistance of hypalon which DuPont invented shortly after.

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I-beam floor
As mentioned here, an inflated vessel will seek equilibrium by attaining a rotund form, be it tube or sphere. A flat inflated plane such as an airbed or an IK floor needs to be a series of parallel tubes – or just a non-inflated sheet, like packraft and white-water raft floors. It also works the other way with bed mattresses. The springs and foam must be constrained by straps or whatever to keep the spring mattress flat.
So this is an IK I-beam floor (left): probably the same tough core of nylon or polyester scrim, but without the impermeable hypalon and neoprene coatings of the exterior panels.
Note the pre-folds or creases to help the Semperit pack flat. I imagine modern IKs do the same, but it all explains the necessary attention to detail which makes ‘tubeless’ IKs like this so labour intensive, compared to ‘bladder’ designs like Aire.

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Twin side-tube IKs like this Forelle, the Incept and Grabner Holidays, have two smaller tubes one on top of the other, rather than one fat side tube like my Seawave (left, red) or Amigo. It gives the same buoyancy, more freeboard (above water height), a slimmer profile (more speed) or make more volume inside (easier packing). The red Seawave on the left is 82cm wide; the Semperit is 72. It makes the boat look a whole lot better too and overall because it’s also no less stable, I’d say it’s the best design for an IK, but it also needs I-beam sections to constrain the two side tubes.

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I can’t say I could suck air through the scrim easily, but I’m pretty sure it’s porous – I didn’t find any transfer holes to allow air to flow between adjacent tubes – they might be a weak point.
When an IK like this is over-inflated (or left in the sun) and is unable to purge through PRVs (none on the Semperit), you imagine it’s this scrim which either tears apart, most probably at the T-join where it’s glued to the neoprene. I tried tearing sections of scrim by hand;  impossible where it was uncut, but as soon as you nick it with a knife it would tear quite easily, like thin cotton cloth. This fabric was at least 40-years-old and had one or two patches of mildew, but was still tough and the whole assembly of the boat has held together amazingly well over the years.

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Where mine failed
Inspecting the fatal second leak alongside the earlier repair, it seemed air was pushing through where two sections of I-beam scrim butted against each other. Perhaps the old coatings stretched differentially here or were just worn out.  It did look like the hypalon was simply flaking away.
I could have fixed that leak but, as mentioned, another would probably pop up whack-a-mole style somewhere else, quite possible while at sea in either my- or a new owner’s hands.

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Glue test
I repaired the big original ‘L’ tear with a 5″ round patch of hypalon and two-part glue (above and left). I then patched a down-to-the-scrim scratch under the hull with one-part Bostik 1782 (left). I used the same glue to repair the initial new leak inside (bubbling water, above).

Although I’m pretty sure they’d have lasted, I could easily pull off the Bostik patches by hand. Pulling off the big round Polymarine’d patch was another matter. It just so happened I’d sawn through the round patch but, only once I got some pliers under a lip (above left) was I able to separate it from the hull. As you can see in the big image below, either the ancient orange hypalon coating of the IK, or the newer red hypalon of the patch separated from their respective nylon cores – the glue’s bond was stronger than the actual hypalon coatings, new or old.


I get a bit lazy about having to faff about with two-part glue, and I also wonder if I ever guestimating the 25:1 ratio correctly. But as you can see, this stuff sticks. If you absolutely, positively want it to stay stuck, use two-part adhesives.
I still don’t know if the second part curing agent merely speeds up the drying process, or is chemically integral to creating the very strong bond. I’d think it’s the latter, otherwise why bother.

There’s more about glues and repairs here.

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Other stuff
The distinctive marine plywood bow has lasted fine – no warping at all and the rivets are still intact.
It may have been an early design solution to easily joining the three sections of the hull in a nice sharp point, though they managed that join easily enough at the back. Maybe it was as much for protection and a frontal tracking aid.
I now have enough hypalon patches and D-rings to see me out. Other images from the autopsy below.

Semperit Mori

Semperit main page
Read the IK autopsy.


A couple of days after trying out the Semperit I noticed a scratch on the hull bottom (left) so decided to pre-emptively patch that with Bostik 1782 (less faff than 2-part). It looked like an old scratch which had opened up by reusing the boat.
I reinflated a day or two later, but a few days on noticed the floor was flat. I pumped it up again – air was hissing from a crack in the hypalon coating inside the boat, more or less under the seat (below; colours enhanced for clarity).


This seemed a bit odd. The boat hadn’t been over-inflated or left in the baking sun, and there wasn’t any obvious rubbing in the two hours I’d used it, though I suppose this is a high-wear area and an old boat.

I suspected general, age-related delamination or entropic porosity. The outer orange hypalon coat can be rubbed or cut down to the fabric core, as with the hull scratch I’d just repaired. But inside should be an airtight layer of neoprene. No way of checking that without open boat surgery.
To be honest, it’s what I half-expected from a 40-year-old IK, which is why I’d kept the refurb to a minimum. I suspect sudden use after many years possible neglect had accelerated decay. I see the keel-strake is coming away too, as are some other black patches holding the rusting D-rings.


I’ve experienced similar deterioration when buying old vehicles for long trips. They seem like a bargain and had a solid ‘they-don’t-make-’em-like-they-used-to’ reputation in their day. But reviving them, or just asking them to perform as they once did, can lead to a string of failures until it’s just not worth it (left). Much depends on how they’ve been maintained over the years. I recall writing in one of my books (or maybe here): “you can’t give your old gran a pair of trainers and expect here to run a marathon without having a heart attack“.

I patched the wear-hole with more 1782, reluctant to waste good two-part Polymarine. Pumped up and filled it with water: all good, but an anomalous perforation somewhere else can’t be ruled out.
That’s another thing I’ve learned with old cars and bikes: you replace the clapped-out engine then the clutch goes; you replace the clutch and the gearbox goes; you replace the gearbox and so on… The strain of refurbishment gets passed to the weakest point. An IK will get you to shore on two chambers, especially if it’s just the floor that’s gone. I had that once with the Incept. Out with your pals on a warm summertime river, that’s no drama. Elsewhere, alone with the wind picking up; not so trivial.

There’s a such a thing as hypalon paint (right) to revive old boats, but that goes for at least £100 a litre – possibly worthwhile on your cherished RIB; not on this old IK. If the hypalon is delaminating from the woven nylon core, paint won’t save it. You’ve got to know when to call it a day, and that day may have come for the old trout.


A few hours later the floor was soggy – this time it had let go a few inches up from the recent patching – the ‘clutch going after the engine’. Up to then I’d been considering putting it back on ebay with a clear semperit caveat emptor. But then I decided sawing it in half would be more fun. I always wondered what an I-beam floor looks like.

Semperum Mare (Semperit at Sea)

Semperit Forelle main page

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No doubt about it; since flogging my much-used Sunny in 2011, followed by a flawed experiment with a Feathecraft Java, I’ve become spoiled by high-pressure IKs like my fast Incept K40 (based on the Forelle’s design), the brick-hard but slower Grabner Amigo and my current lightly modified Seawave. Just 25-60% more pressure makes all the difference, especially once the boat gets usefully long.

I only had my K-Pump Mini to inflate the Forelle after its repair and mods. I’d hand-pumped it up as hard as I dared but was probably a bit too cautious to not over-stress the old trout. Getting in I was reminded of that uninspiring slackrafty squidginess. I should have topped it up after putting in the cold water, but anyway there’s no easy way to accurately check the pressure off lilo plugs (I tried jury-rigging my manometer). Presumably in the 70s the idea of using tough, one-way rafting valves on IKs hadn’t been thought of yet.

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In this under-inflated state and with a slight breeze, tracking away from a headwind was tricky, though I knew that new boats require a quickly acquired knack. As expected, the crumpled keel strip didn’t really do much, perhaps that’s why the Forelle 2 came with a rudder mount. As you can see there’s some taco-ing (folding) going on below me – and this was before lunch!  Without a skeg or a rudder such sagging won’t help good tracking either.


My over-pressure caution was understandable, but thinking it over, I decided the Semp was under-inflated. What this boat needed was a better pump. A couple of days later a £10 Sevylor stirrup pump turned up (I left my super-duper Bravo kite pump down south) and I whacked in what felt like Sunny pressures. With the position of the lilo tubes tucked under the stern cover, and the need to yank off the hose adaptor while pinching the tube to stop air escaping, and jam in the lilo plug, it’s a bit awkward. These plugs really do grip/seal well.

That’s another great thing with running calibrated PRVs on all chambers: you just pump away until they hiss and the boat is correctly inflated while being protected from over-pressure. No need for manometer faffing.

Semperit at sea 2

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Semperit Forelle 2; afternoon refurb’


Here in the Summer Isles the reliable May sunny spell is about to end. It’s been great for solar panels with strong afternoon easterlies, not so good for day-long IK-ing. Suilven mountain even caught fire. Yesterday, before it picked up we nipped out in the Seawave to Eilean Fada Beag (below) and listened to the birds. By the afternoon it was blowing hard.

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High time to patch up my latest IK: an old Semperit Forelle 2 I picked up in Cornwall. The boat was sold with some classic paddles which went straight in the bin, as well as a big tear in the side (right). Plan is to patch that hole, then see if it still holds air.

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Semperit is an Austrian tyre manufacturer who’s still in business. Afaik, their IKs were a bit of a short-lived rubbery diversion in the 1960s. If my 40-year-old boat has no other more awkward leaks, I’ll rig it up and take it for a spin. But first, I scrubbed off a couple of decades of crud and let it dry.

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I wondered about sewing up that L-tear before patching it – the Forelle’s hypalon seems pretty thin, but decided to just slap on a 5-incher. I’ve glued on loads of accessory patches but have never actually had to repair a hole in a hypalon IK in all these years. So I took note of the NRS repair video here: rough up hole and patch: wipe clean with solvent; apply two coats of glue and when knuckle dry apply the patch and roller the living daylights out of it.

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Watching that vid, I saw they used a much better tool for pressing down patches; an ash-handled Sealey TST15 tyre patch roller, unless I’m very much mistaken. The knurled metal wheel embedded in the wooden handle can lay down much more pressure than the wide plastic lino roller I’ve been using.
Just before I did that, it occurred to me stray glue may squeeze through the tear and glue the insides together. Don’t want that nein danke so, with no better ideas, I stuck a bit of paper in there. Seems to have worked.

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With glue left over, I thought I may as well stick on couple of floor patches for a seat base and a footrest tube. As these are non-critical fittings I used any old D-rings I had: a woven nylon one and probably a PVC. I’ve glued PVC to hypalon before for other fittings.

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With them in place I couldn’t resist rigging up the old Trout with a rope-and-pipe-lagging backrest, an old Alpacka packraft seatbase; a drainpipe footrest tube and a lead. All stuff I happened to have in my IK box of bits or found in the barn among the rat droppings. I jury-rigged the K-Pump for nozzeling but haven’t pumped it right up to 2psi as I’m letting that big patch cure for a bit.

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Looking round the repaired boat I see it has rudder mounts; not sure I’ll need one on a 3.56m boat. There are six D-rings on top of the double side tubes but they don’t look like they’ll take the backwards strain of a fabric backrest  Forelles came with wooden backrest bars, (like Grabners who took over Semperit) and which I’ve found prone to bending when used with a firm footrest tube.

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There’s also a squished up full-length keel strip along the bottom. If it works for tracking it will be nice not to have the usual skeg-grounding aggro in shallows or on land. But maybe that keel will slow down turning which is why they have the rudder attachment? We shall see. With twin side tubes the Forelle is just 70cm wide – that’s <28″. But with a thin floor and me sat low in the high sides I’m sure it will be stable enough.
Gumotex still use them for their seats, but the ‘lilo plugs‘ on the three chambers are a bit of a faff for getting a good charge of air.

If the Semp proves viable, I may replace them with proper IK valves. Or I may just leave them as they are. Three £15 Gumotex valves + a £20 PRV will cost the same as the boat, and the lilo plugs can be regarded as their own ‘total loss’ PRVs – when the boat gets too hot they pop! And anyway, there’s no room to fit a big IK valve in the floor as the tubes are too close together. Knock-off Halkey valves go for 7 quid; I might stick a couple in the sides and leave the lilo plug in the floor.


I put it back in the barn with my other restoration project for a couple of days. When I came back it was limp but not draped over that cabinet like a wet pizza. I pumped up and it stayed firm enough, though I’ve forgotten how mushy an 0.2 bar IK feels. It reminds me why I seriously took the idea of trying to increase the rigidity of my old Sunny before getting other IKs. At the beach I filled it with water and stones – no obvious leaks, (or so I thought). A testament to 40-year-old hypalon and glue.

Have to say too, once pumped up, for an IK the old trout is not bad looking. I think the discreet upsweep of the bow, that plywood ice breaker and slender twin tubes make it look a lot less of a bloat than some. Sea trials to follow.

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Does your inflatable kayak need a deck?

Whatever you read here, as much as anything, choosing an IK with a deck is more about personal preference than function.

j2 swil

Most inflatable kayaks are like canoes and have no deck. A few like the Gumotex Framura and Swing, or the Grabner Explorer and Decathlon X500 and some Advanced Elements have fixed decks. Others have zip-back or removable decks.


Above, a yellow Incept K40 with a zip back deck, the one time I used it like that. And later, when I bought my Seawave (above left and below) I got the optional fully removable deck thinking it might be handy. I tried it once, took some pictures, never used it again and eventually sold it.


Other optional deck IKers have said the same: nice to have the option but never actually use it. Both these boats needed fibreglass or alloy spars to support the deck from below and keep it convex to make water run off. It all just adds to more stuff and set-up time.

For me, one of the big attractions of an open IK is it’s so much easier to hop in and out – even from deep water you can easily crawl back abroad which makes it safer. It’s easier to pack or unload the boat (below), as well as dry, clean or work on it.
Any touring luggage will surely be in dry bags anyway and better touring IKs have plenty of attachment points. Best of all there’s no need to faff about with spray skirts and cags to match, and I find it’s so much more agreeable to paddle in the open air and not feel hemmed in. If it’s cold or inclement, I wear a drysuit.


If you come from hardshell or folding kayaks you might think a deck’s a good idea, but length-for-length hardshells are heavier, less stable and less buoyant than IKs. All that means they slice through waves better and sit much lower in the water so need to allow water to wash over the decks. Also, with a hardshell, knee blocks on the underside of the front deck are crucial in the way the paddler interacts with their boat, creating a solid connection for bracing or pivoting against the swell. For better or worse, raft-like IKs are wider and less tippy. Using thigh braces and a solid footrest (below) is about as close as it gets to improving that ‘sat on a log’ IK feeling; you can’t realistically brace your knees under an IK’s fabric deck.


IKs sit higher in the water than a hardshell and swamping only occurs in rough seas or white water, especially in less stiff, low-pressure boats, as I found with my Sunny in Western Australia (below). Rough seas aren’t really suited to IKs, at least not alone, and full-on white-water IKs like the Gumotex Safari, Hyside Padillac or the NRS MaverIK have self-bailing floors so what comes over the sides drains away. But even an unbailing IK will still float when full of water (as I also found in WA), so a bailing pump (left) or more simply, a sawn-off plastic bottle scoop (left) are handy things to carry if out at sea for a while.


The ability to roll is an important skill if using a hardshell in rough water, but you’ll need taut thigh straps and quite a hip flick to roll a typically wider IK, with or without a deck. In an IK, if you capsize you just fall out then flip the boat back over if necessary and crawl back on. With a fixed deck IK that becomes much more awkward (below), just as it is in a hardshell without help, as we found one wet weekend. Solo, a paddle float is essential. Without one I couldn’t do it – and that was practicing in nice calm conditions (below). In dire straits I’d have unzipped the K40’s deck to get back in.
About the only thing I do miss with a deck is somewhere handy to mount nav aids, cameras and other useful stuff in front of you. I get round that with a pfd with pockets and Peli box or a waterproof packbag between my knees.