I think I know what you are talking about...
The game audio said "battleship" but it was a barge with flak cannons...
The only thing I can see why they did this was that you would be 100% outdistanced if it was a real battleship.... it would be half a mile away and you would not be able to shoot it from the shore with what you had...
I think they improvised with a barge with cannons and men on it to be playable... yet (should not have been called a "Battleship" but instead should have been called "War Barge"...
Plus if they used the real Battleship model... it would have been to scale and taken up over half of the map width alone just in true scale.. hehe (which would have looked funny also).
As "wonky" as the audio / voice overs / cut scenes are ... I can see a simple mistake calling a barge a battleship... and not fixing the audio to match.
To properly do a battleship vs shore mission... it would require a completely different map and they probably got to the end and discovered... "oops... our battleship is just too big or not gameplay functional for this map design".
"As amazing as this engine / game is.... it does have some negative issues... but the game is SO good we all just overlook little things like that 
"