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