I've owned a carbon-kevlar construction Xtra for 18 months, paddling through a British winter in all conditions. I bought this kayak specifically for paddling in rough water, mostly in the tide races around Anglesey, as well as surfing.
The basic design features are lots of rocker, a flat planing hull with a relatively wide cockpit section and hard chines, and a very low cut rear deck.
Firstly, it's hard to overstate this kayak's positive rough water handling characteristics. Coupled with a 198 cm whitewater paddle with large blade area to allow rapid changes in stroke rate, this boat is really manoeuvrable in the sort of big confused conditions we get around Anglesey. However, this agility doesn't sacrifice stability, even whilst stationary. Once the hull starts to plane the boats tracks nicely whilst surfing waves and the hard chines allow for very aggressive and positive edging / leaning.
The combination of low rear and raised foredeck make for very easy rolling, and re-entry rolls in rough water are no problem. This boat takes serious abuse and it gets regular hits from the rocks. At 24kg (I'm British, ? lbs) it isn't light, but the build quality can't be faulted and the carbon-kevlar takes the knocks.
This isn't a touring boat, but a fit paddler will still at least keep up with most club paddlers in a group over distance.
Any negatives?
Not specific to the Xtra or TideRace boats: I'd like to see better cockpit outfitting. The Xtra's fit is okay, but play-at-sea kayaks especially would benefit from some better outfitting along the lines of a Jackson, LiquidLogic or Lettmann WW boat, for example. For example, the rigid backband is great, but with repeated rolling the cushion slides to one side and leaves you feeling off-centred - it also tears if you're doing cowboy re-entries.
For handling and enjoyment, it scores 10.
