I have an AIRE PVC raft, dry it very well, then roll it up loosely for winter storage. I store it in the garage where the temperature is fairly constant. Attics have extreme temp fluctuations, so that is not recommended. I leave it on the trailer the rest of the year.
I also have a 25 year old hypalon raft and have also stored that in the garage over the winter, rolled up. It never lost a breath of air until 2 years ago.
Maravia rafts are very hard to roll up any smaller than a refrigerator.