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Equivalent Damage Rolls


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#1 jwsleser

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Posted 05 October 2026 - 12:38 PM

All the naval rules that I have played attempt to address the issue of larger caliber shells hitting smaller ships and its reverse, smaller caliber shells hitting larger ships. These rule sets have mixed results. In this post I will discuss two questions:

 

1. Does the historical record support the need for such rules?  

2. Does the Equivalent Damage roll actually address the question at hand?

 

Wargamers certainly think that such rules are needed. After all, a bigger shell should cause more damage and a smaller shell less. Logical right? In this particular case, the historical record is limited but in the main doesn’t support this assumption. There are four actions to examine: Battle of the River Plate, 2nd Battle of Narvik, 1st Guadalcanal, and the Battle off Samar. I will briefly discuss frequency of hits and actual damage. 

 

Battle of the River Plate was the only one of the three fought at ‘normal’ battle ranges. The 11” guns of the Spee were handier against small ships than the 14” and 15” guns used in the other three battles. In an action lasting a little over an hour (11 game turns) Spee scored nine 11” hits, seven on Exeter and two on Ajax. In almost all cases, the 11”rounds did localized damage as if hit by any size round (putting the object hit out of action), but nothing more. The hit on Exeter’s B Turret didn’t put A Turret out of action, cause engine damage, etc. Using the Equivalent Damage rolls, those seven hits would be 14 hits with those extra hits causing more damage over the length of the ship.

 

2nd Battle of Narvik. Warspite is credited with hitting three German destroyers during the battle with 15” rounds. In all three cases the ships were either barely moving or stationary. Two of the destroyers were already badly damaged from the 1st battle. Again damage was limited to what was hit and the ships were sunk due to the combined hits of Warspite and her accompanying destroyers. The 15” hits alone did not pulverize the destroyers. 

 

1st Guadalcanal. San Francisco was hit by two/three 14” rounds from Hiei. It is stated that these hits were using the bombardment rounds and not AP, hence limited damage. The comment made in the official damage report was that it was the 6" rounds that did the most damage. These two/three 14" hits would be six/nine using the Equivalent Damage Rolls. 

 

Battle off Samar. The destroyer Johnston was hit simultaneously by three 18” rounds, followed by three 6” rounds from Yamato. Equivalent damage would make these a total of 20 hits. Yet the destroyer survived, executed damage control, was able to remain in action for another 2+ hours, remaining combat effective while returning to the attack twice, and finally taking more 6” hits before she was sunk.

 

The ships hit by larger rounds in these four cases survived because these hits only damaged what was hit, it didn’t cause other damage all over the ship. That’s another issue I have with the Equivalent Damage Rolls; the extra hits cause damage anywhere on the ship regardless of the location of the first damage roll hit. Another point that is mentioned in all these cases that should limit damage by larger rounds is that AP rounds tend to pass through (over penetrate) lightly armored/unarmored targets without exploding. HE rounds carried by battleships were still a SAP type of round and suffered the same problem. In all, the historical record doesn’t truly support the idea that a larger shell against a smaller ship should create more damage. 

 

Now one can rationalize these results in many ways and still feel comfortable that the Equivalent Damage roll is justified. It is the reverse of the situations above that finally forced me to recognize that Equivalent Damage Rolls don’t work. What about smaller shells hitting larger targets?

 

In our last battle, my 8” cruisers were firing at PoW (BA armor). The 8” can’t penetrate BA. The Equivalent Damage states 1/2 C-S-T. So only half my hits count and can only caused critical (if the round penetrates), and damage secondaries and tertiaries. Okay so I can at least take out those weapons that threaten my destroyers. Instead of getting a damage roll for each 8” hit, I only get 1/2 a roll for each 8” hit. So four hits is only two rolls. Why? I hit the ship four times, the rounds can’t penetrate, so why the extra penalty when hoping for hits on the unarmored areas? Why doesn’t a smaller round get a chance of damaging those systems which are vulnerable to those smaller rounds? It was this part of the Equivalent Damage Rolls that pushed me into the ‘it doesn’t work’ camp.

 

​Note in the background of this discussion is that it is easier for a larger caliber armed ship to hit a smaller target in GQ3 than historical. The nature of the CRT always allows a roll of '1' to hit and the adjustment for firing at a smaller ship is only up 1 row on the CRT. Once at 15k range, a battleship with 15" (UK CRT) has a 1+ - 2 to hit a destroyer with 3-4 dice. Each hit is x4. This skews the impact of larger caliber guns against small targets due simply to more hits and the Equivalent Damage Rolls modifier. 

 

I feel that the Equivalent Damage Rolls isn’t needed as it doesn’t reflect the historical record. Even if others believe that it is still justified, it doesn’t work as it needs to work. It penalizes smaller guns against larger ships in a unhistoric manner and spreads damage across the target ship instead of concentrating it at the area of impact (assuming that the first damage roll defines where the actual hit was located). If one truly believes that a larger round should create more damage, the game needs a mechanism to reflect structural damage that impacts survivability absent a specific ship system.  GQ3 currently lacks such a damage mechanism. 

 

Comments?

 

v/r  Jeff


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#2 Jim O'Neil

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Posted 05 October 2026 - 08:43 PM

Very interesting and hard to argue against. Food for thought for sure. 



#3 Jim O'Neil

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Posted Yesterday, 01:22 PM

    I’ve been contemplating JWSlesser’s comments and the more i consider what we know, the more sense his comments make.  I believe it was USS Gambier Bay that was taken under direct fire by Yamato, with 18” shells passing through the ship and exploding some 100 yards or so on the far side after going completely through the ship. 

    It’s basically a simple physics problem. All navies used fuzes that fit most all of their guns. So 6” though 16 or 18” guns all used the same delay action fuze. The fuze functioned when it was slowed quickly by piercing a steel plate. The issue is that a 2,000 pound BB shell is not slowed very much by this armor, while a 100 pound 6” shell is slowed significantly more. Simple Physics, the heavier projectile has more mass and requires more to slow its considerable inertia. So while a Battleship projectile will do much more damage if it detonates in a destroyer of lightly armored cruiser, it is unlikely to be abruptly slowed enough to activate the fuze. Thus major caliber shells do best against ships armored against such shells. Now IF a major caliber shell hits something significantly resistant in a smaller ship, it is going to be quite damaging.
   Historically the Graf Spee’s 11” functioned against the relatively light armor of HMS EXETER. Most 8” guns also seem to have functioned when hitting destroyers and lightly armored ships. Note that SCHARNHORST’s 11” were different and are less likely to function in the same situations as the pocket battleships guns and that is a fuse issue; the pocket battleships were to fight cruisers and merchants and thus had a fuze designed to function against lighter plates. Perhaps the best way to differentiate is to say that shells piercing BB armor won’t function against lightly or unarmored ships. Now before anyone screams…yes an 8” will penetrate BB armor at exceedingly close range, so it simply doesn’t explode in lightly armored ships at those ranges! If the shell functions on CA armor, we will assume there is enough resistance to it’s passage to cause it to detonate. If a shell fails to detonate it does 1 hit damage to the target.
 
   Next we have the valid point that a 6” hit in the forward gun of a DD by a shell doing more than 1x damage is unlikely to set off the depth charges. Simple solution is to roll damage until something close to the original hit/damage is affected.

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#4 JAHinson

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Posted Yesterday, 01:49 PM

I wonder about from a game perspective about three things.  First, whether or not the "hit" represents a single shell or whether it represents some sort of aggregate damage?  Second, how do the results overall compare to the historical record so that we get a fun to play simulation that is 'close enough' so that the decision making which is the real fun part for me is preserved?  Third, how stochastic outcomes intersect with determinative outcomes (how much randomness do we want to include in the model and so how much might be attributable to luck?).

 

From RaW:  "Each attack simulates the effect of one battery’s fire at its normal, sustained rate of fire over a three-minute period." and "A damage roll may represent a

single hit, splinters from a near miss or several smaller caliber hits. Similarly, a major caliber hit may result in several equivalent damage rolls." So that could go either way in understanding what a 'hit' is and how damage is apportioned.  Other games I've played have been more clear on whether one is rolling for unique hits by shells (Avalon Hill's Bismarck, for example) or whether it is aggregate damage which might then generate hits on specific areas (Larry Bond's Command at Sea, for example).  

 

Note the above is only for shellfire.  Torpedoes look to be carefully intended to be individual torpedoes striking a ship.






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