Just to clarify a few points :
PU tubes have been used for over 30 years.
The source of the PU has varied, and with it, to some extent, the quality. However for the last 14 years or so practically all of the PU tubes made in the UK and Europe have been made from Chiorino PU, which is of higher quality than all other PU materials previously used and higher performance than Hypalon - I can provide data sheets to anyone interested.
There are literally thousands of PU-tubed RIBs in service with rescue organisations, yachting clubs, fisheries protection, coast guards, navies etc all round the world. The US Navy chose PU after extensive research.
When constructed and maintained correctly these give exemplary service and out-last Hypalon where subjected to harsh treatment.
Hypalon outlasts PU if tubes are left uncovered and unpolished in areas of high UV. The other advantages of Hypalon are that it is cheaper and available in many more colours.
When covering tubes made from any material it is important to ensure that there is good ventilation, otherwise conditions conducive to microbial attack are created.
There have been some isolated issues with glued PU seams due to short-term use of incorrect/faulty adhesive most of these tubes were made some 15+ years ago. Since then the same neoprene-based adhesives have been used as are used for Hypalon.
Anyone visiting the Southampton Boat Show could visit the XS stand for first-hand information - they are one of the very few (if only) companies offering PU as well as Hypalon-tubed RIBs in the UK/Europe.
Am happy to deal with any technical questions.
Chiorino Coated Fabrics Division