I am worried they allow water running through the assembly, sea water is very corrosive and can't be in contact with any interesting materials (e.g. high performance magnets). /*
/* ok they use plastic bearings and stuff, not sure what the magnets are.
The surfboard is interesting. Having listened to some of the issues the wave-glider ran into in order to operate autonomously on the ocean I expect the same sort of folks will come talk to them. I heard a story (and it could be just that), that one of the wave glider experiments was going to be to count whales along the California coast, the plan was to put an active sonar pinger on the robot and ping once an hour to see if there were any whales nearby. The story goes that the project was shelved when the Navy called and informed them they would not be putting active sonar pingers into US coastal waters.
This makes no sense. Active sonar pingers are on pretty much all boats apart from small dingies.
http://www.fondriest.com/news/wave-glider-robots-listening-t...
The whale monitoring I'm familiar with is all passive listening as well. The navy has a long history of pissing off marine mammal experts by blowing things up underwater, so it makes sense that the Office of Naval Research wouldn't fund active sonar. So your recollection has elements of truth.