The sea gasket coil is useful for coiling up large amounts of rope and tying them into small easy to use bundles. This will take a bit of practice. Infact, this video took a few takes to get it right!
Begin with your line ,let six to eight inches of it hang below your left hand if you are a righty. Using your right hand pinch the line and twist one quarter turn. You want to keep all of your loops roughly the same size. Given a quarter twist every time. The twist will help keep the rope laying flat. Once you have a tail twice the length of your gasket coil wrap around behind your coil. Once
you have a tail about the length of your gasket, push the end to the tail careful not to pull the end of the tail all the way through.
Just make a bight or loop and then fold it over the top of your coil. Now pull your tail and you have a nice tight coil.
Watch the link to my video here-