|HMS Argyll. Note the low-to-the-water midships gun and the lower gun on the aft quarter.|
One of the limitations of wargames is the annoying complexity of the real world while the erstwhile wargame designer is striving to keep his game rules reasonably succinct. Actual operations are filled with examples of unforeseen complications that can have a significant effect in a given circumstance, but are very hard to take account of in a systemic way. This is one of the reasons why a certain amount of randomness doesn't bother me in wargames because the real world is fluke-filled.
What prompts this discussion is the additional handicap that the British armored cruisers at Coronel suffered due to the rough sea state during the battle -- a problem generally ignored in most wargames.
On both the HMS Good Hope and the HMS Monmouth, as well as the similar HMS Argyll shown above, some of the secondary guns are mounted one above the other in battery along the broadsides. Presumably there were some compelling engineering reasons for this arrangement -- maybe it eased ammunition handling or simplified construction somehow. But service conditions revealed that the lower gun in the set was too close to the water to be usable if the sea was too rough. This had the effect of cutting the secondary batteries of the Monmouth and Good Hope in half. The Argyl design was somewhat modified as the problem became apparent and only two of the 6-inch guns on the ship's broadsides were still subject to the problem. Eventually in the surviving ships of the Monmouth class the lower guns were actually moved up to the topside deck and the sea-level gunports plated over.
Even Larry Bond's Fear God and Dread Nought rules, which are justly considered exhaustive, only assess an accuracy penalty for gunfire in heavy seas, but don't formally include a way to account for guns rendered completely unusable by the waves. this is the sort of thing that can be handled by scenario special rules, of course, but it requires that the scnerio designer have dome the sort of in-depth research needed and is also the kind of thing that's not likely to be included in a "what-if" scenario. It's the sort of thing to keep in mind, however, when considering the "on-paper" strength of a unit.