Actually duct takes in not waterproof. The best water proof tape is a black pvc tape that is used in plumbing, a heavy duty electrical tape sort of material which is waterproof.
An extra mask should be considered a basic part of the kit becasuse what happens if you lose your mask entering the water? Never happend to me but I've seen it happen plenty of times especailly when there is some surf.
I know one women who carries a complete dive outfit on her boat, including wet suit and bc. Of course it all fits HER...
Or your strap breaks during the dive and you loose the mask, or jumping in off a boat.
A trick is to wear your hood over your mask strap instead of having your mask strap over your hood. It is a pain in the rear end to do that, but you have a much better chance of keeping your mask. I personally don't do that, I am willing to take the chance......so far so good (not for my wife though....she lost one once).
does beer count as an OTC medicine?
Rum?
Oh please let ther be rum...