Graham
This idea was presented on the television programme "Dragons Den"; the entrepreneur is a retired naval officer who has put £80,000 into the development. He put forward a good case for investment with a number of sales under his belt and interest from several retail outlets. Unfortunately he didn't persuade any of the dragons to invest.
No mention of any built in buoyancy or places for bags.
On a positive front i heard through the grapevine that Matt was having a good show with some sales under his belt.
Peter