Tactical Roar

The same: - Scenario were mankind's sea commerce and trade have been halted due to a lot of threat in the 7 seas. -The same situation where humans have to engage in unconventional naval battle with an unknown enemy.  

The same scenario where the human race no longer dominates the seven seas because of multiple threats and has to rely on sea going mercenaries for protection. 

What the 2 have in common: 1. War at sea, where mankind's access to it was denied by some unknown enemy. 2. Mercenaries, who were brave enough to challenge the unknown enemy, except of course the enemy in Tactical Roar are people who were greedy of wanting to monopolize trade, while in Aoki Hagane it involves inter dimensional beings who wants to make the seas their property. 3. Both mercenaries have to use have to use advance tech to combat the enemy, except in Aoki Hagane, they use the same tech that their enemy is using.  

Both have the same story plot where mankind's access to the seas were threatened by an unknown enemy, where their only hope were a group of mercenaries who have the guts and the equipment to take out the enemy.