Tiedown "winch" device

Hi all,

When trying to tie down my new Diamond at our airport, I discovered
that the ropes on my parking spot are too short and I can't even make
two decent knots.

I remember seeing an interesting tie-down device the other day,
something like a hand-operated winch which allows you to tie-up the
cable without having to tie any knots. Does anyone know what it's
called, and where I can get it?

Thanks in advance.

-- C. Dweller