Thanks to Rick for pointing out Neris now have what they call hybrid IKs: the Smart and now the slimmer Smart Pro range of lengthy 1-, 2- and 3-seater IKs with conventional inflatable side tubes, but incorporating an alloy ladder-frame floor plus cross ribs and long bow and stern pieces to give the kind of prow you can’t get with an all-air, non-DS IK.
The hull is made of German Mehler PVC and the inflatable side tubes follow the European convention of being sealed ‘tubeless’ chambers – no water-trapping separate bladders which means quick and easy drying.
Using PVC in IKs can mean once inflated, it’s stiffer than synthetic rubbers like Gumotex Nitrilon. That’s good for overall rigidity but PVC can also be harder to pack when cold and, I believe, is less durable to pinprick punctures. My Incept K40 had all these characteristics.
The Neris websites don’t give side tube diametres or pressures until you unearth the pdf manual (left) which states 0.25 bar / 3.5 psi – the same as a Seawave or Rush and higher than an average IK. That sort of pressure may give the footpump, shown above something to think about. There’s no talk of PRVs either, so let’s assume there are none.
Metal frames originate from heavier folding kayaks which themselves were based on the skin-on-bone or wood qayaks of the Eskimos (left).
The rationale of using a metal frame in an IK seeks to combine rigidity with lightness while dodging the lengthy assembly of full folders (right) and the manufacturing costs of traditional I-beam IK floors (as on my Seawave).
Online blurb for the Pros says: Washboards make the kayak rigid when sailing on waves and other water turbulences. This suggests the boat is not fully rigid without ‘washboards’, and what is a washboard? I couldn’t find out but in the UK, Neris offer ‘floorboards’ as standard which may be the same thing and, if attached securely to the ladder frame, should reduce flexing.
It’s all a lot of gear to carry and unfortunately, the development of high-pressure drop stitch (D/S) panels (left) has made the idea of metal frames and wasg boards in IKs redundant. I’d guess, once built into a boat hull, a 10psi D/S floor as on the Gumotex Thaya (left) is as dynamically rigid as a Neris alloy ladder + floorboard, while weighing much less and being immune to breakages, wear and corrosion.
It’s true that a metal or wood element can support sharp prow forms which cut through the water (or ice floes) better. They may well also eliminate the need for a grounding-prone skeg (although Neris offer rudders and even sails). One downside of flat IK floors (D/S or otherwise) is they track less well, but the well-defined Smart prows see to that.
Some Advanced Elements IKs use similar prow frames, but I’m told are even less rigid unless you insert the optional D/S floor panel and the optional backbone ‘keel bar’ which always sounded to me like ways to get round a poor original design.
My old Feathercraft Java (right) also used alloy poles for support, but with me on board they didn’t really improve rigidity. Their later Aironaut (also discontinued), as well as Grabner and some Gumotex IKs like my Seawave achieve rigidity purely with high-pressure tubes, and my short, 0.3bar Grabner Amigo was as stiff as a plank.
The Neris Smart‘s chunky, alloy ladder with oval-profiled tubes for the floor which supports subframes for the protruding prow/stern pieces as well as the splash-decks and cross ribs for the side tubes.
You do wonder if that ladder frame pressed against the floor sheet could pinch the floor on striking a sharp obstacle. That is an issue with folders and happened in my packraft once. After that I always use a foam heel pad. Doing the same in the Smarts’ ladder-frame contact area may be a good precaution.
Being long for a two-seater, the 4.85-metre Smart 2 would need all the help it can get with rigidity, but it carries 250 kilos and comes in at a claimed 23kg. The boat packs down to a metre long (left), but as with metal frame kayaks, there’s a worry of damage during transportation. I recall that anxiety when I brought my Java back from the US. This is why frame-free IKs are so transportable.
Note the way the side tubes are supported in sleeves by the cross ribs (left) so that should one tube go flat, it will still be propped up by the ribs and probably keep the boat from swamping. Good thinking, as buoyancy will be a little reduced without an air floor. Single or double detachable decks are an option too.
A non-inflated floor ought to mean you sit a bit lower in the boat. That aids stability and thigh straps appear to be included, but it’s a real shame to see the width of the 4.85-m Smart 2 (above) at no less than 95cm. Of course, rigidity and prow forms contribute to speed and efficiency too, as does a backwind and a second paddler, and width creates stability which is important to recreational users with young families. My Java was on the tippy limit for me, but the Smart-2 seems too far in the other extreme, like many US-branded IKs.
In 2018 the slimmer Smart Pro models were introduced. There’s a single ‘S‘ model (left) at 4.77m x 81cm with nearly the same LWI as a Seawave but at 21 kilos, is over 20% heavier. The Smart 2 Pro is a very long double at 5.35m and 86cm wide at 26kg. See the video below. The blurb says they’re a faster version of the SMART-2 with a pointed bow, smaller diameter side tubes, narrower beam and longer bow / stern decks.
Prices start at over £1000 in the UK 9see link above). Here’s a review.
I get the impression Neris Smart IKs appeal more to folding kayak enthusiasts fed up with protracted assemblies but still wanting a big long boat with a firm floor to run a sail. otherwise, these days IK enthusiasts will easily find rigidity in many lighter, high-pressure or D/S IKs.