I've been looking for a simple solution to keep my wallet, phone, and Bluetooth headset dry and secure while I'm swimming, but every waterproof bag was either very tiny, very difficult to open and push things into because of the tacky plastic coating, or expensive and only useful for one purpose.
After scoping out the options at sports stores, I realized I already had a very strong, lightweight polyester day bag so I went bought a large round screw-top container with a rubber gasket and I was done.
easy to put everything in and take everything out, very good seal.
Took it into some crashing waves for an hour with my phone, wallet, and t-shirt inside(and some tissue papers so that I could periodically check if any water was getting in) and the thing works like a charm.
Bonus buoyancy means I can use the container as a small pillow while floating
The water was pretty busy today, but I'll definitely have to try floating again, the neck pillow was very comfortable during the short test runs i was allowed.
This. It's not challenging to make a watertight container. It's challenging to make a water tank container that will remain watertight under various types of duress.