JSP - there are a number of options for what are sometimes called "Rigid Bouyant Boats" - essentially RIB styled boats without an inflatable collar:
(1) Foam filled collars
(2) Aluminium collars
(3) Polythene collars
... (a) from large plastic tube or
... (b) as part of a one piece moulding with the hull like mine
I believe the design intention is to make them much more robust (to physical and UV abuse) than hypalon tubes. Foam filled tubes normally still have some sort of fabric over the top - but punctures don't affect bouyancy. Its very very unlikely you will pierce
10 mm of polythene or 2-3mm of Ali from normal domestic abuse although if you do repairs are a bit more specialised than slapping a patch on - but still perfectly possible.
The only real downside I am aware of (other than the fact that many of the tubes are not as nicely shaped as the latest things that Chris and Paul are churning out - but aesthestics aren't your no 1 priority... you own a SR!), is that people claim that the tubes act as a shock absorber in rough water... I'm not sure how significant that factor actually is - but obviously rigid tubes can't do that. The only way to really tell would be have identical hulled boats with inflatable and rigid tubes skippered by the same person on the same day. With my level of expertise the skipper is a bigger factor than the tubes!