Proposal - Underwater turrets SE2

If in real life you shoot a 38 caliber into water, the bullet will go about two meters. But if you shoot a 50 caliber, the bullet will not go even half a meter, because it will spill into fragments and due to the high resistance of the water when meeting. Therefore, to shoot underwater, you need to use something like harpoons or something more sophisticated.

Harpoon grenade launcher

Shoots in automatic mode about 250-300 rounds per minute. Two ideas, the first is a cumulative, the second is a bullet on the tip that is activated upon contact with the target, or automatically after a very short time. Despite this, in fact, it is a rapid-fire harpoon launcher, but only with an additional fun filling. Should not be single-barreled.

Underwater jet cannon

It shoots a shell-rocket using compressed air. The shell-rocket has a jet engine that works for no more than one second. It has sliding stabilizers. There is a cavitation rod in the bow. After being shot with compressed air, the shell-rocket moves in a cavitation bubble, which allows it to quickly cover a large distance in water. At a certain distance, it self-detonates. Howitzer 200mm. Cumulative. (Possible optimal shell shape is a cone)

Standard turrets are ineffective or of little use underwater. Shooting from the surface into the water is also of little use.