This was Gumotex’s take on Grabner’s Holiday IKs, later reimagined by Incept (I’m pretty sure it’s in that order). In other words a twin sidebeam IK but with inflatable decking so making it an inflatable SinK (sit-in kayak). You didn’t get many of those to the pound back then, though Gumotex now do the Swings and Framuras.

What they said
The Gumotex SEAKER is the first fully inflatable sea kayak worldwide. It is designed for long trips in sea bays, on big lakes and large estuaries. The small volume of the packed kayak and big space for baggage predetermine this kayak to be used for expeditions.
The user appreciates especially how easy and quick the kayak is ready for use. You can inflate the kayak within ten minutes. The biggest benefit of the Seaker kayak is its safety. The hull is extremely stable and enables remounting from the water without the aid of paddle floats. And what’s more – thanks to the inflatable design no water can get into the capsized kayak.

In case you’re wondering, twin side beam – two smaller side tubes instead of one fat one has benefits. And on this model they were made from Mirasol PVC with a Nitrilon deck and floor. The Mirasol was thought to be less elastic and so the Seakers could run higher-than-normal-for-Gumotex 0.25bar. It made the sides taller so less swamping, though of course your deck and skirt will see to that. The interior space is greater and two side beams make the boat flex less longitudinally – a problem with all non-dropstitch IKs once they got beyond a certain length. The drawback was that the boat was taller in the water, so more wind-prone.

Once I thought a Seaker could fill the dark corners where the Sunny did not shine, but at 34kg the solo was more than double the weight of a Sunny, Incept K40, Grabner H2, Amigo or my later Seawave. The high-quality Korean Mirasol PVC was clearly heavier than Nitrilon.
Like a proper sea kayak, it had hatches and a rudder and could no doubt be rolled, but to me, half the appeal of IKs, even at sea, is the SoT aspect. If you want to sit in and want to be portable, get a nice low-profile Feathercraft for nearly the same price, less weight and which looks less like a floating, wind-prone torpedo. It had fittings for an optional rudder, too.
They also did a 2-seater Seaker II but I got the feeling these were exotic, rarely bought boats that were heavily discounted in North America before disappearing around 2014.
It was the end of the line for the heavy Seakers which is a shame because the only thing wrong with them was the weight. Still, I’ve never actually seen one so what the heck do I know about Seakers? A blogger in Canada got one cheap a few years ago but didn’t keep it long. A double went on eBay in 2016 for £410.