Tag Archives: cheap sevylor packraft

Testing the Sevy Slackraft

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I got round to trying the Sevy ‘packraft’, a cheapo PVC dinghy with the outer hull cut off to make it less wide and hopefully more functional.
Compared to the single-chambered Alpacka, blowing it up takes a while. The floor is made of two interlinked ribbed chambers which require a ‘spike’ beach ball inflation adapter that fits on the end of the K-Pump (right). The main chamber fills quickly enough with the K-Pump – a one-way Boston valve ensures you get a good fill of the elastic material and it’s always a surprise to see it stay that way according to the SevyGauge™.

Even then, on the riverbank alongside the Yak it did look very small and rather low in draught so that even with a dry suit, I wasn’t convinced I wanted to get in off a steep, muddy bank. So I set off upriver to Sluice Weir in the Yak, towing the Sevy and intending to shoot the chute for a bit of fun. On the way I spotted a striking blue bird – never seen one of those before. Do you get bluebirds in Kent in mid-winter?

I got in the boat as gently as I could but it didn’t take long to have an inverted Archimedean revelation: the mass of the paddler was nearly equal to the peak buoyancy at the rear of the craft. That’s partly why Alpacka came up with the fastback tail in 2011. Unlike Archimedes, I didn’t jump out yelling ‘Eureka’. I just sat still thinking ‘is it spilling over behind me and if not, why does my back feel cold?’ I took a couple of pics behind my back (below) to establish plimsoll levels, then set off slowly across the pool, with the trusty Alpacka tender bobbing along behind in case the Sevy sank.

This was not relaxed or efficient paddling like in the Yak. I arched forward trying to offload the stern while pulling gingerly through the water for fear of initiating a possibly catastrophic water-bounce that would fill the boat. The Sevy sagged feebly under the weight of my butt and feet, just as I’d seen Jeff’s do on the Fitzroy. However Alpacka do it, it’s the rigidity in their hulls that makes them as good an airboat can be. The multiple coatings on the non-stretch fabric must have a lot to do with that. As expected the short, round Sevyslackraft yawed quite badly, even with the Alpacka in tow to act as a rudder. But that always happens first time out in one of these boats until you adopt a smoother technique. Either way, I was relieved to be wearing a drysuit.

As I bimbled around trying not to sink, the nearby weir boom opened up without warning and suddenly the Medway was kicking out a current such as it had not seen since the end of the last Ice Age. I could barely make headway in the Sev so allowed myself to be swept back to the canoe portage pier where I hopped back into the Yak. Within just a few minutes the river had risen 6 inches or more. I thought it had appeared rather over-full upstream in Tonbridge where I had driven through earlier.
Anyway, the 5-minute Sevy Slackraft trial were complete. To paraphrase Right Said Fred, I’m…  Too Hefty for My Boat, although it will make a nice packraft for the Mrs who’s a little over half my weight of 95kg + winter ballast.

So, packboating newsflash: the Sevy blow-up boat is not for bloaters like me. But as it’s so light I could still see a use for it as a tow barge for a bike or an extra huge payload (not that you could realistically walk with such a load). Maybe a really long river stage, or one where you want to be well equipped on arrival with a huge tent or something.

Skinning the Sevylor slackraft

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Slackraft river trials
Slackraft sea trials

As promised, I’ve invested in a Sevylor Caravelle PVC dinghy. Cost: £34 delivered complete with pump, oars, repair kit, manual in ten languages and a box which is bound to come in useful one day. The heavy-duty Super Caravelle model, as modified by Narwhal, is out of stock in the UK until next summer, although an Intex Sea Hawk is the same thing and can be ‘skinned’ of its outer hull (as in the graphic, right) in the same way to make a lighter, narrower and nippier ‘PVC packraft’ – see bottom of the page. That’s the purpose of what is being done here, in case you’re wondering.

Pre-skinned and rolled up, the Sevy was about the size and weight of a proper Alpacka packraft, but awaft with that dizzying scent of PVC which takes you back to Mallorca in the late 1960s. Fully inflated, it’s too wide to take seriously, but it stayed like that long enough to enable the outer chamber to be surgically removed with a bread knife. Unfortunately, it’s on this outer chamber that the half-decent ‘high volume’ Boston valve is fitted – all the rest (2 floor chambers and the inner hull) get poxy, beach ball-style push-in valves which, in the latter case, take a while to inflate due to the pencil-thin aperture. Perhaps the Boston can be grafted onto the inner hull; what’s the worst that can happen? I’ll find out soon enough as it also took so long to deflate the remaining hull by squishing the push-in valve I decided to cut it out there and then and slap on the Boston valve from the trashed outer hull over the hole (above left). This was the first time I used MEK solvent to clean PVC. This stuff is pretty damn potent and ‘cleans’ the PVC a bit like paint stripper removes paint! Tellingly, it’s also known as polystyrene cement and has uses for welding too, so use it sparingly on PVC pool toys or they’ll dissolve before your eyes.

The squidgey little foot pump (right) is very light, but slow, especially when trying to get enough pressure into the main chamber for the slide-marker to move down and line up with the ‘A’ on the SevyScale™ (below left). This is a pressure guide so you don’t burst your new pool toy – easily done with thin, stretchy PVC and sharp words. But by chance the Sevy valve plug fits neatly onto the end of my K-Pump which is much quicker at inflating. The Alpacka air bag sort of screws into the Boston valve too, but you need a K-Pump to get max pressure.


Testing the newly glued on Boston valve, the boat was losing air, but it didn’t look like the glued-on valve was at fault. As it happens the bath was full so a check revealed a tiny, half mil hole near one of the seams underneath. I’m fairly sure I didn’t jab the boat with the knife while skinning it, so it must have come like that or my carpet is sharper than I think. Lesson: test all chambers in your cheap pool toy before running a coach and horses through the warranty by attacking it with a knife – that’s if you can be bothered to send it back instead of dab some glue on the hole, should it also be faulty.
The oars are mere fly swatters as previously noted. It’s possible they could be joined together into a packrafting paddle, but why bother; there are decent Werners and Aqua Bounds under the bed so the oars can join the scrapped outer hull at the local dump.

It has to be said, once skinned it’s 36″ (91cm) wide, 60″(152cm) long, and no more than 12″ high at the bow, so there doesn’t look to be a heap of buoyancy left over for the likes of bloated boaters like me, but the floor also holds air unlike an Alpacka so a spell on a river will reveal all. As mentioned, if it’s enough to stop me sinking, I may invest in gluing a spare sheet of tough nylon onto the base. It may add weight but will make the Caravette unstoppable; that’s unless a sharp-clawed bird lands on the deck or it gets splashed with MEK.

With half a dozen attachment points cannibalised from the outer hull and glued onto the stripped-down packboat with some Bostik 1782 (right), it now weighs 1550 grams; about half the weight of my current Alpacka Yak and about half the volume once rolled up. So compact, it could even make a flat-water towing platform for the Yak – for carrying a bike for example, as I’m not sure it would so easily fit on the bow, especially with camping gear.

River trials will follow shortly, or I may well head straight out to Rannoch Moor for an overnighter with Intex chum Jon who lives up there – see the vid above from last summer. He has also been inspired to skin his SeaHawk 1 bloat into a purposeful packslab. Might be good to take the Yak as a spare up there; if Loch Laidon freezes up round the edges the ice spikes might be too much for our pool toys.

Slackraft river trials
Slackraft sea trials