Here's a pic of my very basic First Aid Kit. This is the kit I carry with me when not coaching at Water-Venture and during my kayak trips.
The box is a sandwich sized Lock & Lock which is waterproof and floats. But I keep it in my dry bag for double protection.
1. Sterile Gauze
3. 3M Transpore tape
4. Roller bandage
5. Antiseptic Cream
8. Alcohol swabs
Maybe I should add in a small bottle of axe oil in case people get sea sickness.