USS Mackerel (SS-204)
Mackerel-class submarine
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USS Mackerel (SS-204), the lead ship of her class of submarines, was the first ship of the United States Navy named for the mackerel. Mackerel and her near-sister Marlin were prototype small submarines which the Navy was exploring to replace the... Wikipedia
Builder: General Dynamics Electric Boat
Launched: September 28, 1940