Tank and Warship Similarity

Alright listen up, genius. This joke is funny 'cause it's playing on the fact that tanks and warships are both HUGE and HEAVY. Like, duh, they're made of metal and carry a ton of stuff. So saying they have in common that they're overweight is like saying the sky is blue. It's so obvious it's funny. You probably trip over your own feet a lot, don't you?