Hi, everyone. This is just an FYI, in case you ever want to do this. Might save you some time:

I'm repairing deck hardware leaks, and after removing the deck hardware, decided to temporarily cover the exterior holes with tape, so that, using my dehumidifier on the interior, I could dry out the deck core (balsa I assume).

I tried three different kinds of tape before I found one that was truly waterproof - waterproof meaning I could drown the tape-covered hole with a water hose and no leaks would show up below, in the interior side of the hole in the deck.

Transparent duct tape found at West Marine - leaked.

Special aluminum covered "waterproof tape" found at Home Depot - leaked probably due to the lack of flexibility on the standard C36 non-skid deck pattern.

Seafit Premium Boat Stripe "Superior UV and Moisture Resistant" tape - found at West Marine - did NOT leak probably due to superior flexibility on the non-skid pattern. Hooray!

Hopefully I can get the tape and its adhesive off easily in a couple of weeks when I get back to finishing the holes. :-)