This handle was found many, many years ago (I think at a river location) and was consequently chucked into my miscellaneous gear tub. Doing a junk sort yesterday I discovered the engraving amongst the scratched paint - "Mark's Tool"
May be of sentimental value to Mark if he is still involved in windsurfing.... Can anyone help

My tool is considerably larger (probably not as well used) so not me.

Lao Shi?

Not guilty!
I use an extension so obviously not as big as Mark's

Let it be a warning to others if you're missus gives you one, it's best to take it and pull on your downhaul yourself then go for a sail.