It is not a surfboard, and it is not a skimboard. It is something in-between, but Tom Curren approved it.

Last year, S-Wings launched a new fin technology. The French brand developed a collection of surf fins with long tips inspired by Nature. They looked strange, but they promised extra push.
We all know that Tom Curren likes to step out of the conformity box, and that is why he embraced a new challenge. After testing the S-Wings on a surfboard, Curren asked if he could get them on a skimboard.
As we all know, skimboards are finless. But Tom wanted to feel how a thin board behaves with the technology from Guethary.
"There is indeed a real logic in this idea: without a rocker, the skimboard goes very fast, but the curve of the outline and the thinness of the rail make it very difficult to drive. S-wing fins offer this control and add even more speed, as on a traditional surfboard," S-Wings explains.
The video shown below features Jérôme Sahyoun (surfboard) and Tom Curren (skimboard) riding S-Wings fins somewhere in Morocco.