Tag Archives: tpu kayak

Preview: Aquaglide Cirrus 150 TPU hybrid kayak

I hope to be testing a pre-production version of the Cirrus later this year

See also:
TPU The Mis ing Link
Hybrid IK Buying Guide
IK Fabrics

Nearly two years ago I predicted TPU IKs could be the next step and wrote:

[synthetic rubber is good but] … Packrafts, meanwhile, are mostly made from TPU (as well as PVC), a different sort of polymer coating which has many of the benefits of synthetic rubber: odour-free, smooth texture, light, UV resistant, supple (crease-free), not environmentally toxic. But, like PVC, it too can be heat welded. Since Alpacka got the ball rolling, there are now loads of brands banging out TPU packrafts. In this time the fabric and seam technology have proved themselves to be as durable as PVC or rubber, and capable of running higher pressures too. As someone on the internet observed: ‘Thermoplastic Polyurethane (TPU) is the link between rubber and plastic’.

Now that TPU packrafts are well proven, it could be time to ditch PVC and make TPU IKs, assuming the costs can be bearable. The benefits are principally nothing less than a huge reduction in weight.

Aquaglide Cirrus TPU IK
On the face of it the new Cirrus IKs seem to be copies of Aquaglide’s three PVC Chelen models (120, 140, 155) – never seen one but they look to be a decent hybrid. The PVC ‘155’ 15-footer weighs a hefty 42 lbs (19kg) and I bet will fill a large suitcase. Although that weight’s unverified, it actually compares well with other long hybrid PVC IKs and even my old 4.5-m Seawave at 17kg. But unlike a Nitrilon rubber Seawave, in my experience the rolled-up bulk of big PVC IKs can be off putting.

The press release claims the new Cirrus 150 will weigh just 18 lbs (8.1kg); a staggering <50% reduction on the PVC Chelan. Price is said to be $1700, $400 more than the 155 Chelan which today goes for £1150 in the UK. The boat is 15 feet (4.57m) long, 35 inches (89cm) wide and claims to handle 600 lbs (272kg). You won’t need a wheel suitcase (left; Sandbanks) to cart a Cirrus around.

According to the video above, the tubes are double-coated 70D nylon TPU. This sounds low compared to a packraft’s typical 210D hull, but remember denier is thread weight not coated fabric thickness (’70 x the weight of silk’). In the UK IronRaft sell 70D TPU and this MYO chap used it too. It’s at the very lightest end of the scale; 70D PU-coated nylon is what Supai use, though I’m not sure you can compare PU coating with TPU. The fact that the Cirrus will be double coated (most packrafts are now single coated) ought to provide extra support (more rigidity/less sag) without needing to resort to seam-straining higher pressures. One good thing about PVC is that it’s innately stiff once pumped up – good for performance if not packability.

In the vid you can spot the floor pressure is rated at 0.41 bar (5.9psi) and the sides take a healthy 0.21 (3psi) which ought to be enough to give a rigid form without ruptures.

Unlike the Chelan, there appear to be no ‘have-your-cake-and-eat-it’ closeable self-bailing ports which I suspect have dubious value outside of white water paddling to which a 15-foot IK is ill suited. You just get the usual drain port in the back when flipping the boat over will achieve the same purpose. The floor is removable too according to a video comment; a huge benefit for quick rinsing, drying and cleaning. And we’re told the whole boat fits into the shoulder drybag as pictured below.

Price was always an issue with more sophisticated and less widely-used TPU, but now everything everywhere has become expensive, perhaps this matters less? Radical economic analysis apart, let’s hope this starts a trend towards more TPU IKs for folk who want the benefits of a lightweight tandem packraft like my current Sigma TXL, but in spacious and faster IK form.

Let’s end with something else I wrote two years ago:

A few years ago I predicted that full drop-stitch IKs would become the new thing. This has happened and has driven IK design and sales a long way forward. But, PVC aside, I’m still not convinced by the boxy profiles and packed bulk of FD-S IKs. Until FD-S forms can evolve (as the Itiwit X500 has shown), I think hybrid, drop-stitch floors (D-SF) are certainly the way to go, if an IK is to stay undecked, unlike the X500.

There will always be a demand for cheap vinyl or PVC IKs but I predict the next big thing in high-end IKs will be TPU, including removable D-S floors in TPU. TPU is now well proven with packrafts and blends the heat-welding benefits of PVC with nearly all the better attributes of ‘hypalons’.

Thanks to a couple of IK&P followers who spotted and passed on news of Aquaglide’s new Cirrus range of hybrid TPU IKs.

TPU Inflatable Kayaks: the Mis ing Link

See also:
Advanced Elements 2021 AirFusion Evo
Aquaglide Cirrus 150
Zelgear Igla 410 (soon)

Pictures from Zelgear and Marcin S

These days IK hulls are mostly made from PVC. Just three main IK brands still using old school synthetic rubber: Gumotex (Cz), Grabner (AT) and NRS (USA). PVC gets recycled, is made everywhere and so is cheap off the roll and easy to heat weld. But is it only me who finds something unpleasantly ‘plasticy’ about PVC: the stiffness, the texture, the smell and maybe the eco-stigma.

The only PVC IK I’ve ever owned punctured on the slightest thorn and went on to do that with the next owner. And this was supposedly quality ‘Mirasol’ PVC from Germany (to be fair, a mate with an older K40 had no puncture problems whatsoever). I can’t imagine any Gumotex or Grabner I’ve owned ever doing that, not even my many (TPU) packrafts. That’s why I persevered with synthetic rubber IKs, even if it’s becoming an expensive ‘dinosaur’ fabric.

Synthetic rubber coatings like Nitrilon and EDPM are derived from the original DuPont hypalon. Boats must be hand glued which adds to costs. But, just as nothing man-made has managed to beat the properties of leather for crashing fast motorbikes, compared to PVC, synthetic rubber remains more durable and more resistant to UV, lighter, more supple, easier to glue (where needed) and easier fold compactly. After 15 years there was no noticeable deterioration in my Sunny, (below) other than a decade and a half of paddling wear and tear. A synthetic rubber IK will easily outlive a similar PVC IK.

Packrafts, meanwhile, are mostly made from TPU (as well as a few from PVC), a different sort of polymer coating which has many of the benefits of synthetic rubber: odour-free, smooth texture, light, UV resistant, supple (crease-free), not environmentally toxic. But, like PVC, it too can be heat welded. Since Alpacka got the ball rolling, there are now loads of brands banging out TPU packrafts. In this time the fabric and seam technology have proved themselves to be as durable as PVC or rubber, and capable of running higher pressures too. As someone on the internet observed: ‘Thermoplastic Polyurethane (TPU) is the link between rubber and plastic’.
For inflatables TPU is clearly superior to PVC in all ways except price and stiffness (but this works both ways). “It has properties between the characteristics of plastic and rubber. So, it is flexible without plasticizers, and its flexibility does not affect the design or its strength and durability.” Link

In a way, my 3-metre MRS Nomad packayak (left) was as much a TPU kayak as a packraft. With just 2psi or so, it was able to hold its shape (under my weight), but now costs nearly €1400 in the decked version. In 2022 I got a similar Anfibio Sigma TXL (above) which works surprisingly well in IK environments while weighing just 4kg.

Advanced Elements 2021 AirFusion Evo with a PU shell.

The only PU (same as TPU; not sure) IK I know of was NRS’ discontinued Bandit series. It was made in China but was still dropped, I presume due to cost reasons before they started making many more models with PVC. Since I wrote that the Advanced Elements AirFusion Evo with a PU shell has come out. And so has the TPU Aquaglide Cirrus for 2023.

Zelgear TPU IK

While researching the Zelgear Spark 450 preview I found a 2018 ZelGear catalog. It states their now discontinued 5.2m PVC Igla IK can be requested in TPU (or the similar and much stronger Vectran which Alpacka use for their top-of-the-range packrafts). There’s more here. The weight of this long boat is said to be 15kg. The cost? $2000 I was told.

You may wonder if relatively thin and flexible packraft TPU could support a 5-m IK? TPU coating is also said to be more elastic than PVC, but it can’t be any more elastic than rubber. And anyway, a stretch-free scrim (woven core) takes care of that; the coating is primarily for impermeability.

A long IK needs to be a lot more rigid than a relatively short and squidgy packraft. And a lot of that is down to the fabric, not just psi. That’s one good thing about inflated PVC: it’s stiff. You’d think a TPU IK would require very high pressures to support a long boat which would then need bombproof seams. But add a TPU drop-stitch floor (above) to take the load and the tubed sides would be under less pressure, so to speak. This Zelgear blog post from 2018 mentions some “some technological issues are being resolved“. I’m told Zelgear were on it but then Putin made his move…
Pictures below by Marcin S from a boat show in 2018.

With all these Asian-made TPU packrafts knocking about, some using locally sourced fabric whose quality in my experience is as good as the Alpacka stuff, the cost of TPU fabric may drop to a level matching the few ‘hypalon’ IKs still available. The $1700 Aquaglide Cirrus is one good example.

A few years ago I predicted that full drop-stitch IKs would become the new thing. This has happened and has driven IK design and sales a long way forward. But, PVC aside, I’m still not convinced by the boxy profiles and packed bulk of FD-S IKs. Until FD-S forms can evolve (as the Itiwit X500 has shown), I think hybrid, drop-stitch floors (D-SF) are certainly the way to go, if an IK is to stay undecked, unlike the X500.

There will always be a demand for cheap vinyl or PVC IKs but I predict the next big thing in high-end IKs will be TPU, including removable D-S floors in TPU. TPU is now well proven with packrafts and blends the heat-welding benefits of PVC with nearly all the better attributes of ‘hypalons’.