"jamesgangnc" wrote
Drilling a big hole through the the front half of the tab might allow
you to get at that bolt and then drop the lower unit. Or might be able
to chisel the front half of the tab off.

The trouble is that the area you need to go through to get to the through
bolt is the thickest part of the tab. Still could be done, though. What I
was thinking was saw off the fin then drill straight up toward the bolt that
holds the tab on. Once you find it, make a big hole up to it then drill all
around the bolt with a smallish bit until you remove enough material to get
the remains of the tab out.