I live near the sea. I sail and fish and have more than once dropped my keys into the water. I find self inflating keychains, while successful, to be very expensive. Another solution is a cork from a champagne bottle or cork sphere attached to the keys but these are often unattractive. In this Instructable we are going to make use of a knot called a "Monkeys fist". It was used in days of old to store long lengths of surplus rope on ships and rebellious sailors would slip lead weights into the middle of this knot to make a weapon. By using floating rope to tie the knot, a large amount of floating material can be attached to your keys, thats a good thing!
I am a ship's officer, and the fist was used to weight the end of a heaving line to throw ashore, especially in adverse weather with high winds were you may not get a second chance to throw a line, without a re-approach. It works best for throwing with a weight inside and then dunked in paint. The tail should be spliced into the main and the main should be cut to a length that a loop spliced in the end so as to form a eye. The fists can then be stored and used only when needed. You hitch the end of a heaving line to the eye of the fist and let her fly.
It gives new meaning to the phrase, "Grab your balls boys!"
By the way the unions here in Canada had them outlawed due to the shoremen getting unconscious by a dead-on deckhands.
They do make a nice weapon though. If I particularly like a bartender I will whip them up one out of a 1/2 inch nylon line. It will give you a nice soft ball about 5 inches in diameter. You put your hand through the eye and hang onto the main so that it can not be taken from you. It is soft enough that it will not knock you out, but good enough break a few bones in a thieving hand.
The monkey's fist is much easier to create though.
You should really use the "tool" to create the fist....makes it much easier.
http://www.instructables.com/id/How-to-tie-a-monkey_s-fist/