serpentine belt jumps off

[turbotwig]

I have an 87 GN, and I am having a hard time figuring out why the serpentine belt keeps jumping off, usually under hard acceleration. The belt is a Kelly Springfield 635K6 (63.5 in.) and the tensioner seems to be fine. Anyone got any ideas? Thanks, turbotwig

[kenmosher]

Water pump worn (maybe pulley bent or wobbly due to loose bearing?)

Alternator bracket bent or missing the brace that goes to the back of the alternator?