Category Archives: Gumotex Seawave

I used a Seawave for 5 years

Seawave 2: fitting a footrest tube

Owning several Gumotex IKs with the rubbish footrest pillow (left), I came up with my footrest tube idea years ago. It’s since been copied (or maybe just implemented) by many manufacturers.
In a kayak, a footrest isn’t something you rest your feet on while watching Netflix. You lightly brace against to stop you sliding down in the seat and to improve you’re connection with the boat. To that end it wants to be solid, not mushy.
I was never really that happy with my Seawave’s drainpipe arrangement: an adjustable strap running forward from the seat and a counter-tensioning elastic pulling from the bow to keep the tube in position. Too many straps, with entrapment and aesthetic issues. All I really needed to do was glue on a couple of D-rings either side of the footrest, but I like the idea of reversible (non-permanent) modifications.

Then I remembered a clever idea someone passed on to me: straps threaded through a small piece of plastic pipe. You can buy them ready-made to jam into car doors to lash stuff down. As was suggested, these anchor straps could also jam into the cavity/channel you find on most tubed and even FD-S IKs with removable floors, where the floor meets the sides to make repositionable/removable lashing points. Also, they are dead easy to make.

As footrest tube strap anchor points they work especially well because the tension on the strap is sideways (towards the bow) for better jamming, and they can be slid forward along the channel when paddling two-up and beyond the adjustability of the strap. And best of all, no tedious 2-part D-ring gluing required.

Seawave 2: what’s the damage?

Seawave main page

Though not totally convinced by the boat, I planned to buy the new Gumotex Rush 2 in the early summer of 2020. I sold my old Seawave easily but by the time I dithered, UK lockdown discounts had ended. Soon availability of Rushs everywhere dried right up, along with so many other IKs which saw prices shoot up.

Eventually it transpired the Rush wouldn’t be available before spring 2021 (was there some flaw with the new design?). Needing a boat for a book cover, with help from a Czech chum as a go-between, I bought a second-grade Seawave direct from Gumo, saving 15% on the CZ price (Gumo won’t sell these specials outside CZ). This was just before the price went up to nearly €1300. As predicted, Gumotex prices have risen across the board; the Rush will be €1500 for spring 2021!

Defects … are only of a visual nature (abrasions, patches, larger amounts of glue, stamp imprint, etc.) and do not affect the driving characteristics and life of the boat.

Rather unnervingly, the exact nature of each boat’s damage is not specified by Gumotex. It’s the luck of the draw. On unpacking the new boat it took me a while to locate a barely visible patch on the side (left). It may not even be a hole (hard to believe how that could happen in the factory), more likely a scratch or a nick down to the scrim.

Anyway, I’m happy with my Seawave, one boat i don’t mind owning again until something better comes along. The only difference I can see between my old one are grommet/ports for the rudder kit on the stern demi-deck. The new fabric also feels oddly tacky, like TPU, something I’m sure will go away.

The seats and footrests are the same old over-weight rubbish. Gumotex aren’t making any innovations here. Just as with my first Seawave, before the boat got wet the seats went straight on to eBay for fifty quid, bringing the price down a bit. I refitted my proven packraft seatbase/SoT backrest idea.

The useless footrest cushion got chopped down into spare Nitrilon patches and oral valves. For a useless, low-psi item, inside it looks amazingly well made. I plan to re-fit my footrest drainpipe system, and have a great new idea about how to fit and adjust it. More about that soon.

I took the chance to re-measure the Seawave. Yes, it really is just 30” / 76cm wide and yet looks huge in the corridor – the only place in our flat it can be inflated.
And it weighs 19kg with everything in the bag, Ditch the seats (965g x 2) and footrests (411g for both), add a single SoT/packraft seat and a mooring line, and the 4.5m Seawave is a genuine 16kg on the water. Pretty darn good.

An interesting thing was pointed out to me about the Seawave and other tubed Gumboats: they are effectively made from just two big sheets of Nitrilon (plus deck pieces): the red outer/lower and the grey inner/upper (above). They touch at the edges of the floor and join in a flat seam on top of the sidetubes. Simplicity, I like that.

While out, I also had a chance to properly try out my Ortleib RS140 wheeled duffle.

Tested: Tyre pump adaptor for inflatable kayaks

You may have seen these bayonet/car tyre adapters on eBay in recent months (left). The bayonet end clamps into your IK’s raft valve (won’t work on Boston valves). The other end is a regular Schrader valve like on your car/bike wheel. Attach that to your 12-volt Halfords tyre compressor and you can inflate your IK from your car battery. No more of that effortful, back-breaking pumping!

Me, I’ve never seen the value of electric pumps for IKs. You can only use them near a power source and how hard is inflating an IK with a good barrel pump anyway? It seems some think it is

The difference between tyres and IKs:
• a car tyre is a low volume running high pressure (~30 litres @ ~30psi)
• an IK has high volume but runs low pressure (3 chambers of 50–160 litres @ ~3psi). Drop-stitch has less volume but runs much more.

That’s up to five times more volume in an IK but at a tenth of the pressure. I would guess the swept volume of my better-than-average car pump (left) is 3–5cc. My Bravo RED 4 barrel pump is 2 x 2000cc (it pumps on the up and the down stroke).
Even if my 12-volt compressor whizzes along at 1001rpm, it will still take a long, long time to fill a 160-litre IK floor. But for a fiver, I thought I’d prove myself right.

The easiest way was to pump my Seawave’s floor to the point the PRV purged at about 3psi. The actual psi is immaterial but it’s consistant.

No surprise: it took less than a minute to pump up the 160-litre floor with the barrel. With my car tyre pump it took over 7 minutes.
And if you want say 4psi in the sides, or a 10psi drop-stitch boat, the duration of the tyre pump (or effort with the barrel pump) rises exponentially. It will take forever with the car pump adapter and I think the tyre pump would auto shut-off or burn-out before it reached anywhere near 10psi.

I read about portable USB rechargable electric pumps like the Pumteck or Sunta (left) on amazon from just £15. These are great for pool toys, air beds and other low-pressure items which just need a shape, not rigidity.
The Pumteck claims an obscure pressure rating of 4.5 kPa which sounds impressive but translates to just 0.65 psi or 0.045 bar. That is slackraft presure; there is no worthwhile IK that runs such a low psi, so all it will do is save you the easy initial pumping. For a typical 3-psi IK you’ll still need some sort of manual pump to top off and on a D-S IK, forget it. If your back can’t handle a barrel pump, get a Bravo foot pump.

Five years with a Gumotex Seawave

Seawave Index Page

Darn. I put my Seawave on eBay to ‘test the water’ and it went within hours.
Still, it’s an excuse to show some of my favourite Seawave shots in five seasons of fantastic paddling. What a great boat that was. So great that, with nothing better available at the time, in October 2020 I bought another Seawave (left).

Preview: Gumotex Rush 1 and 2 IKs

Gumotex Rush (D-SF)

Interesting discussion
Another detailed online review
All Rushs out of stock till March 2021
See also: Zelgear Spark 450
A D-S floor Seawave is due end of 2021

Gumotex are moving on up with hybrid drop-stitch technology, originally showcased in 2019’s Thaya which is basically an old Solar 3 with a D-S floor to make it more stiff. The new-for-2020 Rush 1 and 2 (left) is the ‘Swing Evo’ mentioned in that Thaya article.

The new Rush models came out in April 2020, just as the pandemic hit and lockdowns/shutdowns spread across the world. It’s also said there was some kind of quality control calamity at the Gumotex factory which led to many completed boats getting shredded. As a result, stock of Gumotex IKs dried up over the summer when post-lockdown IK demand went ballistic. Other IKs came back online but the Rush was put to the back of the queue. At the end of 2020 all boats got the rumoured price hike, with the R2 going up to €1500, even though they will not be available till March 2021.

‘Hybrid’ is a cool word for a kayak which isn’t a Full D-S like a Sea Eagle Razorlite and many others. They’re assembled from three flat drop-stitch panels making boxy hulls (right) which, according to the graphics on this page, may be sub-optimal in choppy waters. Me, I think a full-width flat floor is as much to blame, but the Rushs get round this with raised side tubes.

Derived from iSuP boards, D-S has become a blessing to IK floor design which hitherto had to use I-beams of parallel tubes (left) which complicates assembly and is prone to ruinous rupture if over-pressured, unless fitted with a PRV or the IK is exceptionally well made.

A Gumotex hybrid IK (below) retains the regular round side tubes of a classic IK for better secondary stability (afaiu) but features a D-S floor for much-needed rigidity. However, unique to Gumo, D-S end-panels are also used on the bow as well as shorter and less obvious panels at the stern.


A word about this fabric paraphrased from here:
Nitrilon-Dropstich is composed of a core of 1100 dtx polyester fabric made up of two sheets joined by a mass of threads exactly 10 cm long. Unlike regular PVC-based iSuPs and D-S kayaks, the durable elastomer plastic coating is not glued to the fabric, but ‘pressure-impregnated’ which eliminates delamination risks more common with bonded PVC coatings. An additional layer of polyester-reinforced Nitrilon is vulcanised to the floor bottoms making them double thickness.”

The Rushs differ from the Thaya (1st gen Gumo D-S) with the panels forming a more ‘hydroformed’ bow, another weak point with regular blunt-nosed tubed IKs. The Rush’s bow makes a water-slicing wedge sharp enough to cut ripe avocados.
The semi D-S side tubes are more complex than a D-S floor attached to two round side tubes (like the Thaya and some AquaGlide IKs, for example) and explains the high price.

The vital stats on the tandem Rush 2 are said to be 4.2m long x 82cm wide. Compare that to my Seawave at 4.5 x 78; the Seawave has an 11% better length/width factor (LWF) of 5.77 vs 5.12 over the Rush 2, but those are my Seawave measurements. The side tubes are said to be 19/20cm on the Rush compared to 22 on my Seawave. This and the length may contribute to the load rating dropping to 195kg vs 250 on the longer Seawave. That’s still plenty, unless you’re hauling a moose carcass out of the Yukon.
The official weight varies between 15.5 and 17kg, depending on where you look online. The higher figure is the same as my modified Seawave with packraft seat mod.

Pressures are another obvious difference with the Seawave. The 6cm D-S floor runs at 0.5bar (7.2psi), actually a modest level for D-S, but an IK doesn’t need to be as stiff as a iSuP board.
The slimmer side tubes now 0.25 bar or 3.75psi (same as the Seawave). Well, that’s according to the table from the online manual shown below. Many outlets still list 0.2 sides and so did the Gumotex website until mentioned it to them.

0.25 is a bit higher than normal IK pressure but not quite as high as 0.3 in a Grabner, a Zelgear Spark or the 0.33 bar on my modified Seawave. When you combine that with the stiff D-S floor, the 0.25 sides must make the Rush IKs Gumo’s stiffest IKs by far. The difference is, I added PRVs to my Seawave sides before running them at 50% higher pressure to automatically protect them. The Rushs don’t have any PRVs which explains the warning in the manual, above right. It’s odd but worth remembering that my super-stiff Grabner Amigo didn’t feature any PRVs either, not even in the floor. Quality of construction (gluing assembly) must have a lot to do with it.

When you add any colour you want as long as it’s black, you do wonder if no PRVs is a good idea, because in the sun black things get hotter, faster. Black may be great for Cockleshell saboteurs, not so good for visibility at sea and it kills photos stone dead.
It’s true the Innova-branded Swings in North America have long had black hulls and no one complained. But they run 0.2 bar so need help in stiffening up in the hot sun. They also have fixed decks in red. Many Grabner IKs are now made with black exteriors too (right).
One assumes the Rush’s grey, lowish-psi D-S floor can handle increased pressures from passive solar heating, especially as it’s in the water most of the time. But the black side tubes will get taught which becomes a nuisance to manage (or worry about), even if tubes/cylinders handle high pressures better than flat slabs.
In fact, as you’ll see from the comments below and elsewhere, Gumotex have found black is not notably worse than red or green in absorbing solar heating and dangerously over-pressurising. And if you’re that worried it would be just as easy to install PRVs in the Rush side tubes, as it was on my Seawave.

Because a D-S floor is flat, one imagines it will hinder effective tracking, despite having a skeg at the back. The flat hull will plane over the water and wander off to the sides like a packraft – the so-called ‘[windscreen] wiper-effect’.

So, similar to Sea Eagle‘s patented NeedleKnife Keel™ (right), Gumo added a more discrete ‘keel hump‘ under the bow (left) to compensate for the lack of old-style parallel I-beam floor tubes which added a directional element. You can see from the overhead image above that this keel hump is mirrored on the floor inside the boat, either by design or need. This protuberance makes a high-wear point on the IK in the shallows so it’s just as well the floor is double thickness Nitrilon, as mentioned above. It’s the same on any boat. On my Seawave I pre-emptively added a protective strake – a strip of hypalon – to the central tubed rib, though to be honest it never got much wear as i try and be careful. Mine was hardly worn in five years of mostly sea paddling.

Rushs can be fitted with optional decks (green on the R1, above, red on the R2, below), using the same velcro system as the Seawave, with those horribly bulky alloy spars (right) supporting the decking (surely a flexible rod like tentpole material wouldn’t be hard to make). I read on other reviews that they’ve greatly improved the coaming (hatch rim) so that spray skirts attach more securely.
The footrest appears to be the usual rubbish cushion adjusted by strap and seats can be moved to a variety of positions, too.
Seats are now solid foam, but the base looks too thin and low to me. A stiff foam backrest (with side bracing straps) is good, but an inflatable seat base is much more comfortable to sit on because you can vary the pressure and so the height. Unlike anything inflatable, foam eventually loses its cushioning. But an inflatable seat just doesn’t need to be made of hefty hull-grade hypalon, as on other Gumo IKs (more in the vid below). But anyway, a seat is easily changed to suit your prefs. More on IK seats here.

Below, a review of a Rush by Austrian Steve. Can’t understand a word but some observations: I like his convertible Eckla Rolly trolley/cart/camp chair; also love the lovely long canoe chute at 20:40. Have to say though, I winced a bit at some boat dragging here and there. Do the right thing, Steve; it only weighs 12kg! Note also this shortish boat seemed to track pretty well without a skeg – the frontal keel-hump may be effective in leading it by the nose, after all. But in the comments Steve admits the stiff, flat floor slaps down hard on wave trains coming out of rapids and I suppose would be the same at sea. It’s a drawback of flat, raft-like D-S floors.
See this for an easily translatable written review also in German.

The price of an R1/R2 has already jumped from a hefty £900/£1200 to €1150/1500, plus decks going from £200/310/370 (tandem). There’s also a rudder kit (price unknown) which will be similar to the Seawave unit. IMO it’s not so useful, even on the longer R2. But like decks, some may like the option.

As you can tell, I was comparing the Rush 2 with my 5-year-old Seawave and wondered if it might be time (or an excuse) to change. An unprecedented five years of ownership proves there’s nothing wrong with my Seawave [I sold my Seawave in May then bought another in October].
What are the benefits of a Rush 2? Black is not such an attractive or useful colour for a boat, and neither is losing a foot in length or 50kg in payload over the Seawave – at least at sea. On a river the greater nippiness from less length will have benefits, but for that I have a packraft. As for greater rigidity, it looks pretty good in this clip but my adapted HP Seawave was very good compared to the lower-pressure Gumboats, and it seems the speed (see below) is no greater. Being a bit shorter, I wouldn’t expect it to be.
The word is a Seawave with a D-S floor will be out at the end of 2021 but that will begin to approach Grabner prices. Gumotex had a bad summer in 2020; either due to lockdown shutdowns followed by very high demands for IKs, or as I read elsewhere, a failure in the PES core during testing which saw them ditch hundreds of boats. Who knows, buy by the early autumn of 2020 supply was creeping back, except for the exotic new Rushs.

Good owner’s review (in French)



Kayaking the Swanage Stacks

swanmap

Ten minutes after a paddling away from a tranquil Swanage seafront bathed in a Turneresque light (above), we found ourselves battling a stiff breeze rolling off the Ballard Downs on the north edge of Swanage Bay.
The odd whitecap scurried by, a sign that the IK Limit was not far away. This felt like more than the predicted 10mph northerly. We dug onward, and once tucked below the cliffs the pounding eased. The northerly was probably amplified as it rushed down the south slope of the Downs and hit the sea. We’d paddled through that turbid patch – a bit of a shock before breakfast. What would it be like once out in the open round Ballard Point? Mutiny was afoot.

“Let’s see how it is round the corner, then decide,” I informed the crew.
“Aye aye, cap’n sir.”

We eased around the corner expecting the worst, but were greeted by a magical sight: a line of 200-foot high chalk cliffs receding to a distant group of stacks and pinnacles glowing in the soft morning light and all soothed by a gentle breeze.

OLYMPUS DIGITAL CAMERAIt was only a mile from here to Handfast Point aka: Old Harry, passing several stacks, arches, caves and slots. Ever the goldfish in its bowl, I’d got distracted before looking up tide times, but judging by yesterday evening’s paddle around Brownsea Island in nearby Poole Harbour, it was a couple of hours into its southerly ebb. We arrived at Harry’s about mid-tide but with still just enough water to paddle through most of the arches as well as some narrow slots which were already running too fast to tackle against the flow (below). A bit of a tidal race swirled past the Point, but nothing dramatic.

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I’ve been planning to do Swanage for years and it was even better than expected. It must have been packed out yesterday on the bank holiday, but today, before 9am we had the place to ourselves. It’s a fascinating geological formation and all the better explored from a paddleboat.

Lit by a rising sun and on the top half of the tide must be ideal timing for a visit here. All up, it was only a two-hour roundtrip from Swanage seafront and in similarly good conditions would be easily packraftable from the north off nearby Studland beach.

Hope to paddle this again, one time.PS: Little did I know that this summer 2019 paddle would be out last sea paddle in the Seawave. Not since my original Gumo Sunny on which I learned and did so much, have I owned an IK for so long and had such fun times. What a great boat that was.

Urban kayaking: East London

The plan was simple. Put the IK in at Limehouse Basin where I finished up last week, and take an easy canal-paddle up around what are collectively known as the Bow Back Rivers threading through the Olympic Park, then portage over Three Mills Lock onto what becomes Bow Creek. Here, we’d ride its tight meanders on an ebbing tide down to the Thames at Trinity Wharf. Hard left and, keeping on the north bank (naughty), for what looks like an easy beach take-out at Lyle Park, a mile downstream.

bowmap

The whole 8-mile run included just two locks to portage. Compare that to 13 locks and two closed tunnels for the similarly long Regents Canal I pack’ed last week.
Things didn’t get off to a great start, but next day we were back and on the water before 8am. We set off up arrow-straight Limehouse Cut. Dating from 1770, it’s London’s oldest canal, built to evade the Lee River’s final twisting meanders on Bow Creek which we hoped to paddle on the wat back. (Very detailed history of this river). Two miles on, a thick mat of spongey duckweed backed up around Bow Creek Tidal Locks. Tendrils of weed caught on the paddles and flicked all over the boat.
eastlondonBow Creek ebbs and flows right alongside the near-stagnant Limehouse Cut/Lee Navigation, but this was surely once a single river system. The River Lee’s (or Lea) source is in the hazy Chilterns of north Luton, and reaches the Thames via Bow Creek, 42 miles later. The Lee River Navigation is paddlable from at least Hereford (Mile 27.5). In England, a ‘navigation’ in fluvial terms means a public right of way for all craft, with a precedent going back centuries. Not all rivers in England are a navigation.
This whole underused wasteland between Strafford and Hackney was massively redeveloped for the 2012 Olympics, including the two new tidal locks mentioned. Before that, on the spring tide you could paddle up Bow Creek all the way to Hackney Marshes for some fish and chips. But while great for towpath activities, it seems the developers behind the refurbished network of waterways and new bridges didn’t consider paddleboat access either side of the locks. Odd, seeing as it was the Oh Lympics and all.

deli

Our first trial came at Carpenters Road Lock (booking required a week in advance). It has a unique radial design with gates lifting a bit like a bulldozer blade. The CRT is very proud of it. Even though it’s permitted, as a single kayak I wouldn’t expect to use this or any lock; portaging is always quicker. But I would expect it to be fairly easy to get out and portage around a lock, just as I did 13 times or more last week on the Regents Canal. Maybe I’m going soft, but clambering up a 12 feet of rungs set in the canal wall, hauling the boat up, and then carrying it half a kilometre to the next accessible put-in doesn’t encourage paddling. What next; the cliff climbing finale from Deliverance (right)?

Two miles downriver at Three Mills Lock, (which I read was closed for repairs) we had to get up an even-higher ladder jammed behind a derelict? barge. To access the tidal stretch downstream of the lock, the only way was another long wall ladder, but it was behind temporary barriers. I could have wandered on to the Channelsea River to look for an easier put in, but where it joined Bow Creek (right), a cable or pipe to the crane floated across the surface, blocking the way. On a wild river you portage as long as necessary, sometimes miles. But either side of a lock on an urban waterway, how far do you go?


To be fair I’d timed the tide all wrong. I thought (correctly) that mid-ebb could be a fast run on the Bow, but in my greed for speed I’d failed to appreciate that at the tidal extent (the lock and adjacent Three Mills Island, left, 3 hours before LW at Bow Creek mouth), mid-ebb has already gone shallow. You’d need ropes to get down to a boat.
I suppose the easiest way to do Bow Creek is to paddle up with the tide and then let it take you back –  this must be what local hardshellers do. With a packboat you can dodge such backtracking. But not here it seems. And whichever direction you do it, once you’re in Bow Creek, I don’t think it’s easy to get out of the high-walled channel.
Our East London paddle occurred during a mini-heatwave with temperatures up in the mid-30s. What better place to be than on the water. But not in it: that morning the news reported a staggering three drownings yesterday, all on the Thames and all separate incidents.
Lacking the hoped-for thrill of the Bow Creek finale, the route we took wasn’t so interesting from the water, though would be a nice walk or cycle if you’ve never seen the Olympic Park in real life. From the water, you see a lot of high rises or backs of factories or construction to make more of the former. Even with its dozen or more portages, I found the Regents Canal much more diverse and interesting.

Below, some pictures from our day out.

Limehouse Basin 7am.
A week earlier, covered in duckweed.
A normal-height floating jetty on the east side of the Basin. More of these needed upriver.
Thick weed clogs Bow Docks which drop to tidal Bow Creek for the Thames. But there is no easy way to access Bow Creek from the bank. You must book the lock in advance.
Three Mills Island complex – there’s been a tidal mill here since Saxon times they say. There’s a cafe.
Under the Bow Flyover. The Lee is the notional boundary between the East End and East London. In some pubs it pays to know the difference. Aabout 1200 years ago in Alfred the Great’s time, it was the frontier between Danelaw (Vikings) and Wessex (Anglo Saxon England).
Loads of building all around. London will be utterly brilliant when it’s finished.
How deep is a canal, you ask? This deep, but often less on the sides.
Belladonna and blackberries.
Old Ford Lock (Lee River Nav) to the left. Just after, Hereford Union canal leads back west to the Regents Canal near Victoria Park. We follow the Swan right under the footbridge along the Old River Lea, passing below the stadium. Note the two different spellings of Lee/Lea, Ley being the original Medieval spelling. I realise that nearby Leyton + Leytonstone have the same derivation.
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Nesting heron.
Carpenters Road Lock. How do you get up there? How indeed.
Actually quite easy out of an open IK. Don’t drop the lead!
We could have turned south here under this bridge and taken City Mills River back to the Lee River Nav just north of Three Mills Island and so back down to Limehouse (see map below). A closed loop with no locks which would be an OK canoe or even a SUP. You can rent Moo Canoes at Limehouse.
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Instead, we portage for 500 metres to the Waterworks River. A superb trolley surface.
9am – time for brekkie in a park before crossing the bridge. There are a couple of snack huts here.
Round the corner from the lock, yard-high put in on the west side of Waterworks River. Gate by the steps locked for no reason so down the ramp past a site entrance. Below the bridge is a short ladder and the gravel riverbed is only a few inches deep.
The Swan Highway Patrol.
The famously elegant Mittal sculpture – and some twisted red thing on the right.
Once a quick way to tart up old flats, cladding removal now in progress.
You want your water bottle or what?
Awkward and mucky take-out at Three Mills Lock. This is where your 3-metre lead comes in handy.
Good thing with IKs: light and bouncy.
I walked off for a recce all the way down to Bow Locks but found nowhere to put in – not even ladders. This spot above was about the easiest place, but still required clambering over fences to get to a walkway 9 feet above the bank scrub. With all the attendant construction and secretive film studios, you’d need to be quick to dodge the hi-viz jobsworths. This point is just north of the Three Mills complex where…
…you’d pass almost immediately under the Mill building. There’s a very shallow weir at low tides; maybe nothing at higher water.
View downstream on the bridge above that mill race. This is 3 hours before LW at Bow Creek mouth, but even at HW access is still awkward.
Reluctant to retrace the nearby Lee Nav back through the weed morass and down the Cut to Limehouse, I wipe off the duckweed and roll up.
We set off for the hot two-mile walk back to Limehouse.
Wouldn’t be an urban paddle without one of these!

How to repair a ‘hypalon’ kayak

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

lm-pumper

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.

sw-holes

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

Patch
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: http://www.polymarine.com/advice/hypalon-adhesive-how-to-repair-inflatable-boat-tubes
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!