The basic visibility rules in Command at Sea work well enough, but several incidents during play, as well as continued reading of WW II histories, has suggested several refinements of the visibility rules. In the standard rules, a cued search raises the visibility two tables, but the sighting conditions have not actually improved. The chance of detecting something has, though, because the searcher has a better idea of where to look. These changes reflect this philosophy. The following modifications are not official changes, but an experiment designed to test a different concept. We're definitely interested in suggesttions for changes to them. First, ignore all the distance variations (the "Sigma") in the visibility rules. These can be clumsy in play. Instead, just use the distances on each sighting table as the range at which it is possible to see a contact in those visibility conditions. Once a unit is within sighting range, players can roll once each three-minute Tactical Turn in the detection phase to see if they sight a unit. A player has a 50% chance to make a successful sighting at maximum range, and a 75% chance at 75% of max range. At half of max detection range, the base chance of detection is 90%. Modifiers can affect either the visibility table that is to be used (as is the case now) or the chance of seeing something on that table. The effects of a modifier will either be to modify the visibility table to be used up or down or to increase or decrease the chance of detection. Modifiers that change the table used: These are things that change the light conditions or the transparency of the air. Battle Smoke appears after 10 Tactical Turns of combat. Reduce surface-to-surface and surface to air visibility by one table. It increases air-to-surface visibility by one table in good visibility conditions (75% or better) Ship stack smoke increases surface to surface and air-to-surface ranges in good visibility conditions (75% or better) by one table. Ships emit smoke when they are within 3 knots of maximum speed because of incomplete combustion. Bioluminescence will cause a ship's wake to be more visible in clear night time conditions for air-to-surface sighting. Increase visibility by one table. Ship's wakes at high speed (over 20 knots) increase their chance of being seen by one table. Gun flashes increase night surface-to-surface and air-to-surface visibility by two tables. This includes not only main and secondary batteries, but AA fire as well. Illuminated ships increase the surface-to-surface visibility at night by two tables. Submarine periscope "feathers," or wakes, (speed 5 knots or more) are treated as size class E targets. See 5.4.3 for detection chance. Surfaced subs are treated as size class E for visibility. Ships moving at less than 5 knots are reduced one table in visibility for both day and night. Contrails (formed by planes at high altitude) increase a plane's visibility by two tables in the daytime. Modifiers that change the die roll: These are things that affect the chance of a contact being detected, given constant visibility conditions. Japanese night fighting training improves night surface-to-surface detection by 10% (except against surfaced subs). A cued visual search (told or knowing where to look) increases the chance of detection by 20%. Against an exposed and non-feathering periscope reduce the detection chance by 30% Sighting ships against a land background: In the daytime: -10% At night: -30% Formations of aircraft (3+ planes) increases the detection chance by 30%. The presence of a detected enemy surface group in one area (90° quadrant) lowers the chance of detecting an enemy group in the three other quadrants by 20%. No matter how well-trained, lookouts will be distracted by the presence of visible enemy ships. Firing in 25% or 10% visibility (unmodified) reduces the chance of the firing ship seeing anything by 10% Firing in 5% or 2% visibility (unmodified) reduces the chance of the firing ship seeing anything by 20% Aspect affects the chance of sighting for Size Class E: Narrow Quarter Broad -20% 0% +10% Experience affects the chance of sighting: Recruit Novice Experienced Veteran -30% -10% +0% +10% BT Back to The Naval Sitrep #18 Table of Contents Back to Naval Sitrep List of Issues Back to MagWeb Master Magazine List © Copyright 2000 by Larry Bond and Clash of Arms. This article appears in MagWeb (Magazine Web) on the Internet World Wide Web. Other military history articles and gaming articles are available at http://www.magweb.com