Originally Posted by ZodiacDan
The boat is holding air and has no specific area of concern. It is just generally worn and some areas have slight signs of the weave showing through.
The dealer didn't spend more than half a second (literally) assessing the tubes. Just touched it and said.. no its gone... and it's dangerous to ride on these
Sounds to me (from the limited information) like the dealer is being a little OTT either to get a sale for new tubes or to CYA because north americans are a tad litigious.
Old tubes normally fail in one of two ways:
(1) they just become porous - this sounds like what you might be experiencing, essentially they won't hold air for as long as you would expect. take a pump with you and you will probably be fine. Its more of an issue if you are reasonably far from safety in an environment where you can't safely top up the tubes.
(2) the seams start to fail. these are difficult to repair and on old material (especially PVC) even harder. a burst seam may be impossible to fix at sea. If the baffles are fine a single section deflating should not be an emergency. If the baffles have all gone, one seam failure would mean all your tubes deflate spontaneously.
Neither is necessarily a Mayday! A well designed RIB (I can't comment on your specific boat) should stay afloat even with all the tubes deflated. Certainly with a single tube segment burst or the tubes going soft in the middle of the day you should be able to limp to shore.
Generally unless very well cared for 10 yrs is normally suggested as the life of a PVC tube, and so for a 13 yr old boat your might be able to nurse them on for another couple of years but you do need to plan for the inevitable.