Updated Summer 2020
Since 2019 the Gumotex Thaya sits alongside the near-identical and 20% cheaper 4.1-m Solar 3 (aka: ‘Solar 2‘ or ‘Solar 019‘) on which it’s based, but with a drop-stitch (D/S) floor to greatly improve rigidity. The Solar was not unlike my old Sunny, running just 3psi (0o.2 bar) all round. As you can see on the left, that can get a bit saggy with a well-fed solo paddler. This was the first of Gumotex’s D/S-floor boats, but a basic exercise in simply replacing a floor rather than trying anything more fancy like the Rush of 2020.
Drop-stitch fabric now makes the complicated hand assembly of pressure-vulnerable I-beam floors (left) redundant. A D/S floor is a flat panel with effectively 3-4 zillion ‘I-beams’ (see top of the page) all spreading the pressure load evenly to constrain the form into a plank shape, but at a much higher pressure than an I-beam floor can safely handle. In an IK, high pressure = a more rigid hull = better glide/less effort with barely any additional weight. The only drawback might be that you need a more powerful high pressure barrel pump (above right). The old Bravo bellows foot pump won’t do anymore.
D/S is normally PVC and made in China, but Gumotex have found a way to manufacture the threading and bond or coat a D/S floor with their durable, flexible and environmentally right-on Nitrilon rubber fabric. It can’t be that hard. The regular, normal-pressure 3psi side tubes ought not need the higher pressures I run on my adapted Seawave because the 7psi (0.5 bar) D/S floor greatly aids longitudinal rigidity (see action video below). Gumotex’s new tag line rubs it all in:
‘Made in EU [read: ‘not China’], made from rubber [read: ‘not PV … spit … C’].
The promo video below suggests something revolutionary, but combining D/S with Nitrilon can’t be that much different from doing the same with PVC. It will certainly simplify or speed up assembly and make floors much more resistant to over-pressure damage, low though that risk is with a PRV. Drop-stitch floors supposedly don’t need the PRV necessary to protect I-beam floors from internal ruptures when they overheat in the hot sun. Some UK outlets where claiming the Thaya has a “Safety relief valve [PRV] in the bottom of the boat” but it’s probably just a copy and pasting error. I can’t see one in any pictures and have yet to see a D/S floor with a PRV. The assumption is they don’t need it but some claim that D/S floor won’t last as long as I-beams. Without a PRV, that may be true and much will depend on running the correct recommended pressure, the quality of manufacture/assembly and where possible, leaving the boat in the water on hot days so the large water-contact area keeps things cool.
One positive thing about I-beam floors is the parallel I-tubes (left) probably don’t hurt tracking (even without a skeg). They also enable the desirable curved hull profile of a boat rather than the flat floor of a barge (for the moment D/S panels can only be flat or maybe with a slight curve).
Payload ratings seem to have settled at 230kg and the movable seats are also made from D/S panels. Initially I thought why? For the backrest and footrest that might make sense but of course you don’t have to pump D/S up to the max to get it’s flat form constraining benefits. Footrests are the usual inflatable pillows. I’d replace them with a section of sawn-down plastic drainpipe so you get a solid block to brace against. It makes efficient paddling much easier.
I’ve never tried one, but I do wonder how a flat-floored D/S IK might handle in windier, choppier conditions where an IK isn’t exactly a hydrofoil at the best of times. A flat, raft-like floor will be stable, sure, but it will roll and pitch about more. Also, according to the specs (left) the Thaya is a disappointing 6 or 9cm (3.5″) wider than the all-tube Solar 3 (Actual verified width seems to be 34″ or 86cm). Great for family-friendly stability; not so good for solo paddling speed and efficiency. My Seawave is 2cm narrower than a Solar 3 and, with the usual care getting in, stability is not an issue. Out at sea my Seawave would be swamped long before I’m tipped out. But then again, the near-rigid floor may cancel out the drawbacks of the greater width. At 18kg the Thaya is heavier than a Solar 3 but you imagine the plain floor will roll up more compactly.
For most recreational, flatwater users the Thaya ought to be a nice family boat, but then so is a Solar 3. The Thaya’s rrp is 20% more than the Solar 3 whose days may be numbered.