HELP: hull stress cracking

[WordMan]

Long time lurker, first time poster.
I've got some stress cracking that concerns me, but my experience is limited.
Hoping this is minor, but expecting the worst.
Seeking group wisdom, how bad is it, repair methods, etc.

A little history if that helps.
Bought my '71 20SF from a guy on THT 3.5 years ago.
For 2.5 of those years the boat was lift kept.
The last 10 months it was bottom painted and left in the water. It was used regularly the whole time, and is now back to being lift kept.
When I pulled it out it had some blistering, but what concerns me are the long stress cracks along the first chine up from the keel.
The boat has an Armstrong bracket, and a 200 Merc.

Thanks up front