I was working on a similar one recently maybe a tad smaller and it had PVC tubes. They were in bad condition and falling apart. I think that was partly down to owners abuse.
It they are original tubes they will be Hypertex, PVC coated fabric. Hypalon glue won’t work but PVC two part will; make sure you prime each surface first with MEK.
It they are original tubes they will be Hypertex, PVC coated fabric. Hypalon glue won’t work but PVC two part will; make sure you prime each surface first with MEK.