The crack in the skeg tells you that it is not strong enough to take the loads being put on it by the rudder
. If you are lucky the problem can be fixed by grinding off the glass and replacing it with a thicker and heavier grade. If you are unlucky the problem lies within the wooden core
which is flexing too much and fracturing the fiberglass. Fixing that would involve rebuilding the entire skeg to be heavier and stronger then glassing over it.
I can't comment further because I know nothing about the construction of the skeg.
The crack in the keel
seems to be following the lead - hull
join. Chances are the boat is telling you that it cannot handle the weight of the lead. If you are lucky the solution will be simply to tighten the keel bolts
with a torque wrench because they were not tight enough in the first place. If the nuts do not respond to tightening then you know that the section of the skeg where the bolts are attached is not strong enough and has sagged. The $64 question is whether that sagging is a one off compression
of the skeg and has stopped or that it might continue due to lack of strength in the core
of the skeg.
I do not know enough to comment further on this issue either. I can say that dropping the lead off a hull
skeg is a seriously big job. For starters you will probably need a custom cradle
to hold the hull during work and the yard might well insist on the rig being removed before work starts.