seabaldy: just don't have the time to keep this up and running. Here are some tips for a submerged cache:
-Even monofilament used for Tuna Fishing line wears down and breaks over time. Rubberized stainless cable might do a little better over time, but will likely still corrode in saltwater.
-A LOT of cachers didn't know how to keep things watertight. I should have stressed this in the cache directions. We used a nalgene bottle at first. People didn't tighten the bottle very well so things got wet. A very generous cacher donated an Otterbox (a brand of watertight box). Some cachers didn't know how to snap it shut and the contents got wet again.
-BIG thanks to the Port of Seattle for putting up with the cache as long as they did. I know that it probably pushed the boundaries with security and all that.
Have fun with the spot!