Deck Gun Crew

[Kirby_TFS]

After my last patrol I was awarded a new boat the USS Drum. I have a little renown and thought I might do some upgrades while in port. Upgraded the radar and sonar along with the twin flak guns and upgraded the deck gun. Happy as a lark I'm off to see. I come across a lone merchant and thought I'd try out the improved deck gun. "Man the deck gun - fire at will"..........nothing happens. I go down to chew some butt in the crew quarters and see that there isn't even any slots to put seamen on the deck gun. In fact my icon for the special abilities is hiding under the seaman manning the flak gun. I go to the deck gun to fire it myself and it's not available with the enemy in sight. I have to use a torpedo to take him out. As I'm crossing the ocean I go back to the crew and still no slots, but I can access the deck gun manually. It even fires! So on the next merchant I try again and it is not available! Heck of a partol without the deck gun. Hopefully when I get back in port I can get the crew straightend out. On my previous patrols I had 2 people assigned to the gun, so I really didn't pay any attention before leaving port. Has anyone else experienced this?