Hello again Rick..
You have a little of everything on that
The smaller cracks all over is Crazing .. the longer ones are stress cracks. Then you have all those little pits from water getting under the craze and popping bits out of the gel.
You could go 3 ways.. cheap..decent DIY job..or Top quality full blown do it right restore
First off you fix all the repairs accordingly.
Cheap option. prep bottom with 80 grit and 5 coats of Interlux Interprotect 2000 .. prep and paint it.. done
DIY .. grind and fill as many "stress cracks" ( the long ones ) as you can. Sand the gelcoat off..apply 5 coats of Interprotect 2000.. prep and paint it.. Done.
Top quality.. Sand all coatings. repair whatever you see damaged in the glass.. Put 2 layers of 1.5 oz mat with poly resin...hot coat some gelcoat over that. fair out with long boards 80 grit . ( or 8" soft pad ) . Spray Gelcoat. ( If you go this way ill explain how ). Blocksand with wetdry 320,400,600,1200 buff. done
YD.