The 'random' algorithm used in the game is somewhat lacking in the 'random' department les green01. Sort of like, if you have a 4 in 10 chance of something happening, the game wants to get the "4" out of the way and be done with it. Just like how the weather can get stuck, similar can happen in other aspects of the game, such as group spawning, and the "duds" encountered. It does make for some interesting patrols, such as 18 duds, with a run of 10 in a row, and the next patrol only having one. Don't forget that you can have torps running too deep, as well as pistol issues with both magnetic as well as impact settings.
@ mark bonamer: I'll check on that... - actually, you have SpyRon listed as your mod. Was that Yamato with FotRSU?