Sure its worth keeping. As a downrigger weight........ok, I am not a fisherman, so I dont know if it would really work for that, but what about a counter balance for a barn door? You could run a rope through the open port and hand other weights to it. Oh, Yeah, and you could use it for catapult amunition for those pesky varmints, and and and, lots of stuff you could use it for. Other than powering your RC airplane with of course [&:]