Slackrafts

See also:
Who makes packrafts?

To the untrained eye a cheap vinyl beach toy looks like a real packraft. Until you paddle one.

Several years ago I persuaded various paddling chums to buy cheap vinyl rafts. If I’d known these boats were around earlier, they’re something I may have tried myself before buying a $1000 Alpacka. Check out my posts on the Intex SeaHawk 1 and similar dinghies here and here.

To the untrained eye a PVC beach toy looks like a real packraft – until you paddle one. For the money spent there’s little to lose, although there’s much to be lost when the thing develops a leak as you cross the Solway Firth or rupture it while glancing off a blunt twig.

Knowing what I now know, having done multi-day tours with mates in France, Scotland and Australia in slackrafts, my feeling is that the heat-welded seams of these vinyl cheapies is actually fairly reliable: it’s usually the material – a soft PVC vinyl film with no fabric core as found in a proper packboat, which lets them down when they snag or get abraded.

This needs to be clearly understood:
slackraft material is like a thick bin bag or the blow-up globe: a plastic film.

sur-row

A proper packraft is like a tent or tarp; plastic coating on a woven fabric core like a tent or a cag. The woven core stops stretching as you inflate it and so enables higher pressures, while the coating makes it airtight. A slackraft will also be airtight but because pressures can’t be high, will always be mushy, under-inflated blobs.
That, and the excessively wide hull that’s actually designed and shaped for rowing (above) are the main flaws. For kayak-style paddling you effectively propel the boat ‘backwards’ with the squared-off stern pointing forward, because the additional volume to give paddler buoyancy is designed into the rounded bow (much as the original ‘fastback’ Alpackas designed it into the stern). You can sit at- or on the stern of a slackraft (we’ve tried all ways – see video below), but there’s little draught there. Depending on your weight, you may swamp the boat.

sev-abkids

My Alpacka Yaks have been ten times better than all these boats put together, but are they worth what was then 25 times the price? The answer is probably yes, and even more so now TPU packrafts from China are half the price of an Alpacka. My Alpacka will last 28 times longer and certainly give 32 times more paddling enjoyment. At the end of our Australian Fitzroy River (adventure, experienced sea and WW paddler Jeff, couldn’t wait to see the back of his Bestway. At the bridge he gave it away to some local kids (left).

Paddling stern first doesn’t help, but another reason these boats paddle slowly is because they’re limp and over-wide – typically achieving 60% of a new-shape Alpacka’s top speed, as we found in the Kimberley (3kph v 5kph), above. Width means stability, safety and wholesome family fun. Most buyers of these kind of boats don’t give a toss about speed as the idea of day-long paddles, let alone overnight touring is patently absurd.

There’s not much you can do about the limp pressure because, lacking a stretch-proof fabric core, pure PVC expands like a party balloon until it bursts. These pool toys often have crude guide marks on the hull (left) to make sure you don’t over-inflate them. Proper packraft material doesn’t stretch so you’d notice. When they’re full, they’re full and most manage that with just lung pressure. If two of you pick up an Alpacka from either end with a backpack inside it, it stays pretty rigid. An Intex or Bestway will fold like a lilo.

I got an email from Narwhal showing me how he’d cut off the outer chamber of his £32 Sevy Super Caravelle to get a much lighter, noticeably narrower and more compact boat. The squared-off stern stern is reduced too. You could do the same to an Intex, Bestway or similar.

Cutting off the outer hull

As you can see from the generic Sevy graphic left, the outer hull is not the main bulk of the buoyancy, despite what appearances suggest. Of course, no matter what Sevy claim, it’s still made of PVC vinyl, but I get the feeling the ‘Super Caravelle’ range is to the plain Sevy Caravelles what the ‘Sea Hawk’ brand of Intex is to their cheaper pool toy- and lake boat ranges: a slighter thicker PVC with multiple chambers, to satisfy some nominal US NMMA marine safety certification. It has an I-beam floor too, but you’ll still have to be a lot more careful with it than a proper packraft.
Warranties are typically 90 days but if it lasts longer than that you automatically get a telegram from the Queen. You can get a bit blasé to a proper TPU packraft’s toughness. It was so nice on the Fitzroy in Australia to treat my Yak almost like a hardshell, while Jeff had to nurse his Bestway all the way, and still had three flats.

Once peeled of its excess (above), suddenly Narwhal’s bloat acquired proportions one could do business with, even at the cost of a little buoyancy. Like most people, he’s 15-kilos lighter than me, but his pack in the photos was a deliberately heavy 25kg which is 10kg more than you’d carry in the field. And a great side benefit is you get to lose all those naff pool-toy graphics and branding! That alone is worth at least £29.95 inc. VAT. As Narwhal explains:

I did this with my 32 quid Sevylor Super Caravelle this summer – ran the Lugg and parts of the Wye and Severn on it, crap water levels but still satisfying. 
Rucksack has over 25kg in so it’s severely weighing me down as a deliberate test as I’m just on our pond.
Weight is now 1680 grams [3.7lbs – my modified Yak is about double that] with excessively and messily glued attachment points, it was 1596 before attaching them.

sev-topview

New Measurements:
Tubes are roughly 8 1/2 inches in diameter.  [Alpackas are 10″]
Length – 163cm or 64 inches  [My Yak is 88″, old Llama was 80″]
Width 83cm / 33 inches  [Most Alpackas are 36″]
Inner length – 107 ish cms / 42″  [Yak is 46″, Llama 51″]
Inner width – 43 cm ish / 17″ [My Yak/Llama 14″]

sev-frontal

I’m 5’11 and 78kg and I was sitting a bit wonkily, did get back in to check it’s not always like that. You still need an effing huge and annoying pump if you want to inflate it nicely, but it handles so so much nicer than before. Now I need to get myself a wetsuit and take it out in the east of Scotland, my new habitat. You might even be able to scavenge some pfds out of the two sausage-chamber keels that get cut off too [see graphic above]. Didn’t think about that; they stay intact so it’s possible.

On the Ardeche Steve and I did talk about cutting off his outer chamber to speed the boat up. It’s now clear from the Sevy graphic that that doesn’t mean you lose masses of volume and so, buoyancy. And of course you can use that excess material to beef up the vulnerable areas – under the heels, the bow and stern and probably the butt. Or cut out and re-use the mounts as Narwhal did.

Packraft historians will see that Narwhal’s cut-down Super Carousel bears a passing resemblance to the legendary Sevylor Trail Boat (left) – the Lost Prince of Slackrafts. It’s no longer made because subsequent US safety regs required multiple chambers to gain type approval. Clearly designed to paddle narrow bow forward, and not row, the Trail Boat looks like one of them Al-Packers! And is that an elbow valve I see in the top left corner? That suggests that it could be lung inflated or topped up. There’s another one on the yellow thing – a seat?

The question is, is it worth the effort to still have a fragile-skinned ‘packraft’, even if it’s quicker than its multi-chamber donor blob? It could be if you’re baulking at ordering a £500 TPU packraft. And at least Sevylor is a dedicated inflatable boat maker and not a Chinese, anything-you-like-in-PVC factory. After all, way back in the 1950s Sevylor were among the original inflatables. As Narwhal observes, he’s ended up with a 1.6-kilo slackraft (a kilo less than my Alpacka) including glued-on attachment points, and that can still carry a hefty load. The draught looks a bit low which means easy swamping for heavy folk, but that only matters if you’re not dressed right or are where you shouldn’t be in a £30 paddling pool.

Anyway, for thirty-odd quid I couldn’t resist it and ended up with the thinner Caravelle (14 gauge not 16g – a fraction of a mm). If nothing else it made a nifty guest boat and as I have a sheet of ‘ballistic nylon’ lying around I glued that onto the floor.
For the real thing I [had] my Alpacka Yak, which after Australia has proved itself a tough old boat. But then for what I paid, so it should be.

Thanks to Narwhal for the photos and the idea of trimming an over-wide bloat into a super cheap pack raft.