In the scenario, even a tower with three inches of protection is only about 50 percent effective against three-inch and five-inch gunfire. The exchange takes place at longer ranges than those expected in many real destroyer fights. At closer ranges, officers also need a clear view from the bridge, which an enclosed armoured position can hinder. The conning tower therefore protects imperfectly while restricting the command work it is supposed to preserve. That combination makes its expense difficult to justify.
Notable Point · 37:57-38:21
The conning tower as an expensive compromise
Conning towers offered too little protection and obstructed the view officers needed in close action, making the expense hard to justify.