I saw this thread
www.seabreeze.com.au/forums/Kitesurfing/Review/GoJoe-truly-safe-board-recovery?page=1 and decided to try it out with a tube from bunnings:
Absolutely rubbish! The water from the board was spitting up and hitting the tube causing me to reduce speed and even crash. Biggest waste of $10 ever. At least some local kiters got a good laugh out of me though.