Maybe everybody already knew about this; but I thought these were the first USCG certified thermoplastic fuel tanks that I have seen that were approved for use on and in COI vessels. INCA company.  

And, this just in.  Profligate just discovered the same thing; different company.  And big cash savings.  http://www.latitude38.com/lectronic/lectronicday.lasso?date=2013-11-04#.UngdAXCsiSo