Sorry, attached a wrong photo to the prior post... here's #17.

   <Marv>

"""
[We added a single ventral fin to Ted Noel's IVP... moved the tie down
receptacle into the upper edge of the fin. Attached photos show the submerged
fitting and its location inside the fin. The blue foam in photo 17 was used
to protect the threaded area during the layup process... the fitting was made
from a block of 3/8" thick steel (to match the 3/8" foam core in the fin)
welded to a threaded rod that matched the threads in the original tie-down
receptacle. The original tie-down eye simply threads into that fitting from
the side. <Marv> ]
"""