Here is the full list of all 23 Victory At Sea achievements.
Sink at least four enemies in combat with a fleet of submarines.
Win all the historical battles.
Sink ships from each ship category.
Own at least one ship of every category.
Complete all the campaigns.
Complete the Atlantic campaign as USA or Britain.
Capture an enemy operative.
Complete the Mediterranean campaign as USA or Britain.
Earn five hundred million warbonds in a single campaign.
Capture fifty ports.
Complete the Pacific campaign as USA or Britain.
Sink three combat ships in battle when commanding a single ship.
Sink six combat ships in battle when commanding a single ship.
Earn one hundred million warbonds in a single campaign.
Sink one hundred ships in campaign mode.
Recover covert intelligence.
Sink twenty destroyers in campaign mode.
Sink to the bottom of the sea.
Capture an enemy captain.
Complete the Atlantic Campaign as Germany.
Complete the Pacific Campaign as Japan.
Complete a campaign on Hard difficulty.
Complete a campaign on Expert difficulty.