Decided that drybags could be a cheap but durable DIY floatation idea. Purchased a couple of 80 lt bags for £16 the pair & filled with electronic air-filled packing (about to be thrown out ) These multi-celled thingies are almost impossible to burst ( I think they housed computer equipment )
They equal in volume the YAK's I have in the red canoe so I'm confident of their worth should they be tested.
The drybag material is very resilient & TBH they wont let you ( or themselves) down in the event of accidental puncture un-like the YAK's.
Filled with polystyrene or balls as has been suggested could solve a quick but necessary fix. Anything is better than nothing but regards looks ? - - - - - not too shabby !
Will lash the bags in before adventuring