gCaptain is reporting that, since 2012, the Irish Naval Service has been experimenting with using kite sails to give their ships a fuel saving boost and to hoist aloft surveillance equipment up to 300 meters (1000 feet) into the air. They now consider the technology mature enough to be commercialized.
Putting sensors at 1000 feet gives a horizon distance of 38.7 miles compared with 8.7 miles for a more typical height of 50 feet.
The Irish Naval Service, their missions, and their ships look more like the US Coast Guard than the US Navy. This technology might have applications for the Coast Guard. Perhaps it is worth a look by the Research and Development Center.
It looks like the Navy may be working on something that looks similar, TALONS, but is only intended to hoist sensors, not improve fuel economy.
Chuck Hill's CG Blog 
http://photos.marinetraffic.com/ais/showphoto.aspx?mmsi=244163000&size=
Just a tad too slow for patrol.
Not necessarily. You would be running engines as well as having the kite aloft, but you would need a strong wind from abaft the beam for it to contribute anything to the propulsion.
On the other hand when we looked at TALONS I assumed they would not be able to keep the sensors aloft if the wind was abaft the beam, but as long as you had sufficient relative wind, you could keep it up, and maybe help power the ship.
Still there is the issue that if the search requires changes of course, the wind may or may not be cooperating.
I meant Rainbow Warrior. Proper sales get around the problem of kites. Though of course there are a few modern alternatives to fabric.
Cutter Northland (WPG-49) 1927
The USCG has been using tethered balloons holding radars at least 20 years ago in the GOM.
Jim Umberger
Yes, those were “Aerostats” but for some reason they were used for only a short period.
Model rail roaders say there is a prototype for every thing.
I don’t think much of a Greenpeace as an organisation ((though I am glad of any and all opposition to whaling)) but I do like the current Rainbow Warrior.
Do you have source info on this painting. I have never seen it before. Definitely the Northland.
http://www.theroyalcourt.info/uss-northland.html
Thanks