See also the similar KXone Slider DS (old model right).
As predicted at the end of my IK Construction article a couple of years ago, before long someone was going to make a decent fully drop stitched IK. It seems Sea Eagle in the US and Slider sold out of Germany have done just that with full, 3-chamber DS kayaks developed by Woosung in South Korea and made in China.
Sea Eagle’s single and tandem Razorlite IKs are a slick and lean pair of one-piece (non-envelope) boats that, in the 4.73-m tandem form, might well be a contender for a very fast IK. And setting aside the fun element of speed, a fast IK is an efficient and safe IK on which you can range further or retreat quicker.
I don’t claim to have any experience of this new boat: it’s all speculation from the Sea Eagle website and other sources. Like many US-branded IKs, Sea Eagle made some hugely wide bladder boats which are great for standing up and fishing from while your dog scratches his ear, but are less suited to actual IK touring which is what we like here at IK&P.
The 473RL RazorLite double (or a solo with space for touring gear) is 4.73m (15.5′) long and just 76cm (30″) wide. It weighs just over 17kg (38lbs) and the ‘tubes’ are said to be 10cm thick giving a massive rated payload of 340kg (the floor may be thicker). Line that up against my latest IK compassion table (left) and those numbers are very much in the ball park. The 473 is over 20cms longer and a couple of cms narrower than my current Seawave which is among the faster of the light touring IKs.
For the full story on drop stitch (DS) technology click the link. Short version: the mass of non-stretch ‘space yarn’ stitched between the two woven fabric surfaces of a hull panel (right) enable much higher pressures while crucially constraining the necessary flat shape from ballooning out. We’re talking up to 10psi (0.7 bar) which is more than double even what better IKs can run. Pressure has long been the weak link with traditional ‘lilo’ IK floors which need I-beams (right; a similar idea to DS) to retain a flat shape. I-beams are expensive to make and vulnerable to damage or rupture when over-pressurised through neglect or carelessness. That’s why most IKs I beam floors need Pressure Release Valves to purge excess pressure before the floor blows, and why faster IKs have slimmer and more rigid twin beam sides to make a less wide and more spacious boat. I’ve owned them and it works.
Easy-to-make single round tubes can handle high pressures but take up a lot of space which makes for a wide and tall but also cramped IK – one of their biggest failings. DS panels get round all of this which is why this new boat could be a real innovation for IKs. The panels are the boat, they are not, as with many American-branded IKs, a series of bladders or tubes that pump up inside a shell or envelope. That is a cheap way of doing it but can have drying issues. For that reason I’ve always preferred ‘tubeless’ single-piece IKs.
High pressure is also desirable in an IK t0 reduce longitudinal sagging under a single paddler’s weight. Some manufacturers use metal frames to dodge this, but in my experience that is a clumsy solution.
The answer is a high pressure hull – be it my currently adapted Gumotex Seawave running over-pressure 4.8psi sides with back-up PRVs, Grabner’s solid 0.3-bar build quality which eschews PRVs, or adapting established DS technology into an IK form. Using this the Razorlite 473 can attain hardshell sea-kayak-like lengths (and so, speed) because the 10psi DS hull makes it as rigid as a plank; the boat won’t ‘taco’ or fold up between waves as most long 2psi IKs will do. DS floors have long been used on iSUP boards (right).
It looks like the Razorlite doesn’t get too sophisticated with contoured or variable panel thicknesses – I’m not sure if that is even possible with DS yet. But even then it looks much more like my old twin side beam Incept K40 which was a slim, fast but stable IK. It’s notable that there are no PRVs in the Sea Eagle’s hull because the evenly spread support of DS space yarn and the gluing can handle temporary over-pressurisation when a boat is left on land in a hot sun. The boat’s smaller volume also means it’s quicker to inflate than a comparable regular IK, despite the effort of reaching 10psi.
The Razorlites feature a pair of drain valves in the floor. Not sure why there are two or why they even bother. To drain an open IK surely you just flip it over. Both seem another thing to go wrong or break as people seem to have already found (see below). Some of the reviews have also complained that the boat is hard to dry fully and water collects in crevices where floor meets side, but it’s hard to think where if the boat is simply three joined panels. Air it down flat and wipe it dry, like a Gumotex (right).
According to the specs the fabric is ‘1100 Decitex Reinforced’. Reinforced what? There seems to be a word missing, a calculated ambiguity which doesn’t do Sea Eagle any favours. That missing word is of course ‘PVC‘, the devil’s fabric. But not all PVC need be nasty slackraft material, as this page explains. It may not be considered very green anymore but the PVC is applied as an air-and watertight coating over a polyester fabric base, just as with ‘rubber’ Hypalon and all the rest. That is the trick to a stretch-free and therefore rigid inflatable hull that doesn’t swell up like a baboon.
The Razorlites also feature rigid molded ends in the one-piece body to help slice the boat through water. This element of hydronautics is typically a weak point on ‘broad nosed’ IKs (right) where a sharp bow and stern are hard to fabricate from regular inflatable tubes. The bulk of these rigid fixtures may make the Razorlites less easy to pack compactly but are bound to bring performance benefits on the water.
Not for the first time I see an IK manufacturer introduce ideas I’ve tried on my IKs. In Sea Eagle’s case it’s a simple footrest tube with an adjustable strap which I came up with a couple of years ago. It’s so much simpler, versatile and effective than some of the feeble ideas I’ve seen used in IKs.
On the right, my latest version in the Seawave used on the weekend. It uses an elastic up front to counter-tension the adjustable foot tube strap and keep it in position while enabling easy adjustment to and fro plus quick removal for cleaning or drying. In any kayak, a solid footrest helps you connect with the boat and pull in powerful strokes. And as an IK doesn’t have the benefit of a hardshell deck to brace knees under, without knee braces, a footrest is all the more useful.
Over in Canada IK World ran a comparison between her old style Sea Eagle FastTrack and the 393 solo Razorlite (left and right; their photos), as well as giving a fuller recreational review of the 393. You may like to scroll down and read some of the reader’s comments about issues and returns they’re having with the Razorlites. She mentioned the new DS boat was less stable but to me the ‘stability’ of the yard-wide FastTrack is beyond the pale – plus it kills performance. I am by no means at ease in tippy kayaks but 76-cm on the 473 is still 30-inches and I felt quite safe in my 69-cm wide K40 right up to the point when it was coming in over the sides (knee braces helped greatly, I admit). The Razorlites appear wide but the sides actually taper inwards towards the floor, so it’s narrower than it looks. The boat comes with an easily fitted slip-in skeg that pretty tall so will drag in the shallows. Perhaps that flat floor needs a big skeg to keep it on track.
I’ve never been a great fan of Sea Eagles’s regular, PVC shelled sofa-wide IKs (exemplified by that awful thing on the right) but good on them for upping the game with the full DS Razorlites. It’s a big step in making IKs less ‘bloat’ and more boat and many people are already mistaking them for hardshells. The solo 393 is going in the UK for about £720. The Tandem 473 is listed for $1400 in the US or a £1300 ‘package‘ in the UK. That is a lot of money for a kayak but on target for a fast, light, easy inflating and spacious IK which you can carry on a plane or in the back of a car.
Most pics from Sea Eagle