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Slackraft Sea Trials

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Chopping down my Sevy pooltoy into a slackraft lost too much buoyancy to take my gross weight, but it works fine for the Mrs who’s about half my weight. So on a very calm, sunny morning – realistically, it’s inshore limits – we took the Sevy out to the Bay for a swim. I’d glued on an extra outer covering of ballistic nylon to save the vulnerable floor, as we had planned to take it down the Escalante river in Utah a couple months back, but it was way too hot for that when we got there and since then, as you may know, much of the US has been suffering a terrible drought.


As often, the first paddle in a short boat like this sees the operator yawing from left to right like a crowd watching a ping pong final. After a while, though the paddling technique adapts to reduce this effect, but even then the boat is still much slower than an Alpacka. This Slackie is only 28″ wide by 56″ long – 2:1 – (my Yak is 88″ x 36″; 2.44:1) and the Mrs found the best trim was sitting in the middle, even if this meant nothing to lean back on and was not sustainable. Next time out we’ll take a fishing buoy or something to lean against, although I do wonder if some sort of trailing skeg – a board sticking out the back rather than an under hull skeg like on an IK– might help subdue the yawing and so direct the effort in a straight line rather than zigzags.

My Alpacka skims along just like it always does; what a great boat it is. Annoyingly the backrest is leaking again from the twist valve base, even though it’s been glued up once. I find you do need that backrest to sit correctly in the boat, so another repair is due.
We dipped about, followed the river channel and out to sea and on to the rocks. As the tide turned we headed back up the river, against the flow the slackboat soon slowed to a near stop and it was faster led on its string through the shallows until a tailwind helped blow us back to our shoes, by now stranded some 200m from the water’s edge in just an hour.


A post-sea trail inspection showed that my carefully glued floor was coming away from the Sevy’s PVC hull like damp wallpaper; that may have explained why the boat got so slow coming back. The Evo Stik didn’t take to the hull at all, or if it did, seawater soon dissolved it. At the time I was trying to save on my nice Bostik 1782 which I used elsewhere on the slack boat with no problems. Anyway, it’s not worth wasting any more glue on this boat. And who knows, perhaps the ribbed floor which has been exposed again may help restore some tracking. We’ll see next time. We’ve half a mind to repeat last year’s fabulous Suilven triathlon, but this time in a boat each.

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.