Slippery ships

http://www.bbc.com/future/story/20120326-slippery-ships-and-cramped-canals 

I saw something like this when I was in Costa Rica in 1976. I met a drunken American engineer who explained the golf ball theory. This worked on the principal of dragging air along with the dimples in the golf ball. This gave the golf ball less resistance, greater range & speed.

In his case, he plus the US Army Corp of Engineers had indented the hulls of a 25ft Piver Trimaran with a small ball peen hammer giving a dimpled affect. He claimed a 15% increase in speed under engine or sailing and  less fuel being used motoring. No proof.  

I wanted to try it, but could never find any one with a boat I could take a hammer too. Now, 36 years later, air bubbling has turned up!