Sometime in the late '70s or early '80s there was a research program in Japan on using sails on large freighters or tankers as an assist. I haven't been able to find it in Google though...

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[link|http://www.dcss.org/speedsl/current_sail.html|Here] is a little information on previous attempts. [link|http://www.vims.edu/GreyLit/SeaGrant/vmrb14-3.pdf|This] also discusses some earlier efforts:

Although certain larger vessels just over 200 feet in length are experimenting with sail-assist (the 3,000 DWT Greek cargo ship MINI LACE and the 1,600 DWT Japanese motor tanker SHIN AITOKU MARU -both discussed at the conference), the most immediate adaptation of the concept seems to be better suited for smaller vessels. Overall investment to either retrofit or design and construct really large vessels for sail assist would be so great, most conferees agreed, as to limit a quick response to the sail-assist alternative.

However, Wind Ship Development Corporation's award-winning retrofit sail design for the MINI LACE appears to be providing the vessel enough fuel savings that a reasonable payback period will result.


A paper with pictures is [link|http://www.nmri.go.jp/trans/Staff/fujiwara/ISOPE03_fujiwara.pdf|here].

Cheers,
Scott.