Iron Man, Vol. 1 #94 (1976)

Frenzy at Fifty Fathoms!
With Abe Klein and Krissy Longfellow the captives of Kraken, Iron Man is forced to listen to what the madman has to say. He soon learns that Kraken has deduced his secret identity, and captured Iron Man to gain access to Stark and his industrial complex, which he plans to use to produce weapons in massive quantities. Stark is returned to the surface wearing the clothing of a pirate. The mud on his boots leads him back to the correct undersea cave, where he recaptures his armour and breaks Abe and Krissy free. His battle with Kraken ends when the cavern floods. Iron Man led the other captives out, but Kraken's peg leg was caught in a crack in the floor. He is presumed dead, though the local innkeeper revealed on the last page bears a striking resemblance to the villain.
Release Date: 1976