I would not recommend this for a Kayak shower curtain for 3 reasons..
#1 it is see through and it does not provide any shower privacy...
#2 you need at least 10 gallons to take a good shower and that is an extra 80 lbs of weigh or you would have to release up to 4 yellowtail...
#3 Jorge showed is a week ago how dangerous it is to stand up in a revo via go-pro...
Could you just imagine if he was naked when he fell in and he did not have pants and his PFD on...
very dangerous...and as Matt would say it is not a good thought! you will just say "fud it" after 1 shower and decide it is better to shower when you get home