Tbh, the majority of stuff labeled "swimming" is really just me sinking to the bottom of the pool. So its status as actual training is debatable :P
Is the sinking thing an exercise? Do people have to come rescue you or do you have to see how long you can hold your breath, or something like that? Or is it for fun? :O
Haha no, it's for a class, and I'm not actually supposed to sink. We're supposed to do stuff like the surface ditch, which is... here, this will explain it better:https://www.youtube.com/watch?v=g_ZCpCy7-Ns
They don't call it Rock Swimming for nothing...