Straight Running Torpedo Attacks

by Guest Writer Don Simon

 

Introduction

WW II era destroyers were, by today’s standards, relatively small vessels. Although capable of high speeds, they carried no armor and thus succumbed relatively fast to battle damage, if hit. Their 5″ gun armament was generally useful against their own counterparts or smaller vessels, but against an armored capital ship they weren’t likely to be the victor in a guns only shooting match. However, most WW II era destroyers carried a powerful torpedo battery, one no capital ship commander could ignore. For the above reasons, destroyers can be described as “Eggshells armed with hammers”, or in the case of Japanese destroyers armed with the Type 93 “Long Lance” torpedo, “Eggshells armed with sledge hammers.”

Destroyer Command (DC) does a very creditable job of simulating straight running torpedoes. In addition, the player is provided with a fairly realistic and useful torpedo director station (F12). In this article I will touch on the technical requirements of the straight running torpedo firing problem. Pattern running and homing torpedoes are not simulated in DC and are not covered here.

Torpedo Advantages/Disadvantages

Like any weapon system, torpedoes have their advantages and disadvantages. DC does a very good job of simulating these advantages and disadvantages. Here are some of the factors to consider:

Advantages

  1. Massive damage per hit. Even battleships can not ignore this weapon.
  2. Fire and forget. Once launched it requires no further guidance from the launch platform.
  3. Difficult to spot. Especially at night or in low visibility, the target may not even know it’s under attack until KA-BOOM!

Disadvantages

  1. Slow missile. A torpedo is, in general, not much faster than its target, and in some cases it is even slower. This results in large “lead” angles and long run times, giving the target more opportunities to evade.
  2. Limited number of torpedoes carried. The most number of torpedoes carried by a US destroyer class was 16 aboard the Bagley/Benham/Gridley class, and the destroyers of most nations carried about half that number.
  3. No at sea reload capability (except Japanese destroyers). This factor, along with 2, above, make torpedoes a sort of “Silver Bullet.”
  4. Killer robot. Be careful of where you shoot these weapons. Once launched they have no friends and there are no means to self destruct them. They will just as easily blow your friends out of the water as they will your enemies.

Basic Problem

As with any weapon system, one must be within the weapon’s release envelope to even have a possibility of a hit. In naval parlance the weapon’s release envelope is called the Torpedo Danger Zone (TDZ). This is the first part of the problem. Once in the TDZ, the aiming problem must be solved. However, just being in the TDZ and solving the aiming problem does not say anything about the probability of a hit. The optimum firing position is influenced by the aiming problem itself and the ability of the target to evade the attack. In general, one wants the torpedo to cross the target’s path at a right angle in order to maximize the hit probability. In addition, one wants to shoot from as close a range as possible in order to minimize the target’s opportunity to evade.

 

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