Rob & Wim’s FLAT TOP Variant Rules
Introduction – This is a compilation of Rob & Wim’s rules interpretations, house rules to suit our “style” and fix game mechanisms we considered to be problematic, rules modifications for enhanced play in Vassal, and adoption of published errata, optional and variant rules with or without further modification. When our changes appear in the original game tables I have tried to remember to draw your attention to them by using a red coloured font.
Note: Rules bracketed by “2PNR>” and “<2PNR” apply only to two players playing without a referee, i.e. not “double-blind”.
Prepare for Play
Half Hexes, Deployment & Cloud Movement - For purposes of deployment and cloud movement, the horizontal row of half hexes dividing the northern from the southern sectors belongs to the southern sectors. The three vertical rows of half hexes dividing eastern from western sectors belong to the eastern sectors.
Operations Charts Setup
4.1.6 Japanese BB and Float Planes - If a Japanese BB wants to carry a single AF then replace one Zero with one Rufe in the Japanese counter mix and assign the Rufe to the BB. BBs do not have to stop to launch float planes and there are no special costs or requirements to do so. In the turn it recovers the plane, the BB’s movement is restricted to half speed.
AFs Starting Positions – All AFs begin the game grounded at their respective bases or plane-handling ships. None begin the game airborne.
Weather
6.10 CV or CVL Movement Reduction During Launch - If a CV or CVL uses more than its minimum LF it may move only 0 or 1 hex. If it moves 1 hex it must do so into the wind.
Altitude & Cloud Effects - AFs flying at “High” altitude are above the clouds, AFs flying at “Low” are below the clouds. Cloud modifiers applied to Search, Shadowing, Anti-Aircraft Combat and Air Attack Combat die rolls only apply to AFs flying at High altitude. Aircraft searching from “Low” altitude now have a smaller search radius on the Observation Table.
Observation
7. Units On-Map Are Always Observed – Any enemy units that are on-map and visible to you, are always considered to be “Observed”. Friendly AFs sent to attack such units do not have to roll a Search die roll to locate them.
7.3 Plot AF Searches - All AFs that wish to search and all AFs that intend to move this turn, both those heretofore hidden and those presently on-map, must plot their search path before any one of them begins to search. In VASSAL this means you must move the AF with the option “Movement Path” turned on to trace the path.
2PNR> Before the moving player moves an AF that wishes to attempt a search he must reveal its movement path on map to his opponent, i.e. switch the AF counter from “Invisible” to visible. Remember to hide the AF’s number using the “Hide/Restore AF#” menu option, before making it visible. <2PNR
If the search is successful, the opponent or referee must reveal the first location at which a contact occurred. The searching aircraft may then deviate from its pre-plotted path but must re-plot and reveal the full remaining altered path before continuing its move. Each time the condition number changes or a sighting is lost or gained, the searching AF may alter its path but each time must pre-plot and reveal as above.
Subsequent AFs may not deviate from their plotted flight paths to compensate for failed searches by other AFs. They may deviate from their pre-plotted flight paths to respond to their own successful observations or successful observations by other friendly AFs. This simulates radio communications between them.
When an AF wishes to deviate from its plotted flight path in response to a successful observation by another friendly AF, it must first have spent an equal number (not equal proportion) of movement points along its own original plotted flight path. Use one of the new search icons to indicate the point that a sighting was first made so that the number of movement points expended can be easily counted.
2PNR> Hidden Search Rolls Option - This is for two players without a referee who want to experience the same suspense as the double-blind system and who trust each other.
Option 1: The searching player’s opponent rolls the die secretly (a real D6 not Vassal’s D6). If the search is unsuccessful or if it is successful but there is nothing to be seen, the opponent simply declares “You see nothing”. The searching player now does not know whether his pilot is asleep or whether there is indeed nothing to be seen.
Option 2: For players playing via LAN in the same room (like Rob and I do), you can still roll your own die (a real D6). We roll it into a small box so that we cannot see our own roll. The opponent then looks into the box and declares whether or not the search is successful. <2PNR
7.3.3 & 7.3.4 Search Results Computed For Each Hex Individually - Do not apply the search conditions in the starting hex against the whole of the search movement. Do make a single die roll, but modify that roll by the search or weather conditions of each individual hex searched.
7.3.4 Searching When Leaving a Storm Hex - As per the preceding two rules, an AF may begin searching in the first non-storm hex it enters.
7.3.5 When to Begin a Search - Units are NOT required to be on map at the start of the turn to search. Units heretofore hidden may be placed on the map at any point during their movement and may initiate or terminate a search attempt and commence observation at any point during their movement.
2PNR> If planning to commence a search part way through a turn, the searching AF need reveal only the relevant portion of its movement plot (see 7.3 above) so as not to reveal where it came from. To make a partial path, place the new Search counters on those hexes that define the path to be revealed and then erase the actual path. <2PNR
7.9 A Failed Search Lasts the Whole Game Turn - On map AFs that failed their search attempt during their own aircraft movement segment may NOT observe during the opponent’s movement segment. An AF that is unable to search is unable to do so both in its own and in its opponent’s portion of the turn, i.e. for the whole turn.
2PNR> To remind yourself of the status of AFs that failed their search die roll, mark them with a “No Search” counter. You should set it on “invisible” so that your opponent cannot see it and discover that he has failed his search roll rather than that there is nothing to be seen. <2PNR
7.9.1 & 7.9.2 Coast Watchers At Night – At night, Coastwatchers’ ability to observe diminishes. The new Coastwatcher Observation Table incorporates the changes.
7.10 Radar Does Not Negate Normal Observation - Radar complements visual observation, it does not replace it. A base or ship with radar can observe visually as well as use radar. The Observation Table, has been altered to reflect this fact. The condition number for a Base or TF with radar observing AFs on a clear day at range 0 has been changed from condition 2 to condition 3.
7.11 Search Radius of TFs – To more closely reflect line-of-sight realities at sea, the observation distance of TFs has been reduced from two hexes to one. Condition numbers are unaffected. Exception. A burning ship can be seen by another ship at a range of 2 hexes. The only information given in this case is, “You see thick black smoke on the horizon.”
Searching High & Low & at Night – Aircraft at high altitude see farther (on a clear day, but may be obstructed by clouds. Aircraft at low altitude don’t see as far but are not obstructed by clouds during the day. At night they see better than those at high altitude but clouds may still obstruct useful light from the moon and stars. The effects are printed in the Search, Shadowing and Observation Tables.
2PNR> Semi-Hidden Ships as Radar Pickets – The following describes how to use ships with radar as search pickets without revealing the ship types. Imagine that you have three USN destroyers with radar set up as a picket line. Keep them “invisible” from your opponent and stack one US Search counter with each of them. Make the Search counter visible and switch on the Search Radius 3. Your opponent will see the search counter with its radius of effect and will know that there is a ship in the hex but will not know what type or how many. If he sends and planes into or through your picket he will be observed. <2PNR
Shadowing
11.8 Plotting Shadowing Attempts - If an AF or TF intends to make a shadowing attempt mark it with one of the new Shadow counters. There is no need to make a full plot.
TF Movement
12. Orientation of On-Map Units - On map AFs and TFs have to be placed with the top of the counter facing in the direction last travelled.
12.7.3 – Temporary Seaplane Bases – CAVs and AVs may launch and recover float planes even if they have not anchored to establish a temporary seaplane base. The benefit of anchoring is that it doubles their MC and Maximum LF and permits them to handle seaplanes as well. Recovering planes costs a full turn stationary.
Plane Movement
2PNR> 14.13 Special Interception - This modification prevents the unrealistic sneak attack that is possible when an AF attacking an enemy base or on-map ship refuses to search and thereby avoids triggering the interception criterion that interception can occur only between mutually observed units. (14.13.1 & 14.13.2).
Although it is contrary to the rules for the non-moving player to place units on map during the movement portion of the opposing player (7.17), the non-moving player, may at his discretion, place on map any number of heretofore hidden AFs containing exclusively interceptors that are located in the same hex as a friendly on-map ship or base the instant any new enemy AF is observed by the respective on-map ship or base.
If the enemy AF wishes to discover if there are other types of planes or more AFs in the air over his opponent's ship or base he will still be compelled to roll on the search table to find out.
AFs that are located at a range of one or two hexes from an on-map plane carrying ship or base follow the normal rules, i.e. they must be deployed on map to be able to observe and intercept. <2PNR
MF at Low Altitude – Planes that spend at least one movement point at low altitude have their MF reduced by 1 point for the turn. For purposes of this rule, launching, landing and moving to low altitude in the last hex of movement are all considered to have spent one movement point at low altitude. Dive bombers that dive to low altitude during the Combat phase, are not considered to have spent one movement point at low altitude.
This rule replaces the game’s Optional Rule #8 – Altitude Effects on Movement – Instead of doubling the movement costs of planes flying at low altitude we have decreased all movement factors by just 1 MF. Almost all published cruise speeds of the game’s aircraft show a difference of less than 2 MF between high and low altitude.
MF of the Japanese Kate – Although published aircraft specifications vary considerably, all agree that the airspeed of the Japanese Kate has been severely under-rated in this game. Consequently we have increased her MF conservatively to 8.
RF of Armed and Unarmed Planes– With the exception of the game’s long-range search planes (Catalina, Emily & Mavis), all planes that are unarmed throughout their mission may add 1 RF to their range factor. This is less than the historical reality but it allows us to add a little more historical flavour without tinkering too much with the game’s original design.
Air Attack Combat
18. Situtation Example – A friendly AF attacking an enemy base harbouring enemy ships fails its search roll. Who may attack whom? Answer: The friendly AF may attack the base but not the ships since in the heat of the moment, it has failed to spot them. The ships however, may still fire their AAF at the attacking AF, because the AF has been spotted by the base and is attacking it.
18.5 B-17s Combat Factor Reduction – MacArthur’s B-17s were “notoriously inaccurate”, especially against ships moving at sea. Reduce their BHT attack factors as follows:
vs Bases: Level bombing at high altitude, GP 13 reduced to 10, AP 5 reduced to 3,
vs Ships: Level Bombing at high altitude, AP 2 reduced to 1.
Damage
Critical Hits 1. - During Combat Resolution for any type of combat, if a player rolls a ‘3’ or ‘4’ and at least one hit is scored, there is a possibility that a Critical Hit has been inflicted.
2PNR> Players may chose to keep the actual nature of critical hits secret from each other so that only the effects may be observed. However, if playing in this manner, it must be disclosed if a ship is on fire provided its opponent has a TF or AF within range to observe the burning ship. For this purpose, TFs are considered to be able to observe “A cloud of black smoke on the horizon” at a range of two hexes. <2PNR
Cumulative Losses
Speed Reduced to Half: A ship that suffers more than one instance of reduction to half speed is crippled and has its movement factor reduced to zero. The ship may regain movement once the cause of the movement penalty disappears.
Readying Factor Halved: A plane-handling ship that suffers more than one instance of its Readying Factor reduced to half, has its Readying Factor reduced to zero. The ship may regain Readying Factors once the cause the Readying penalty disappears.
Fires
1. While on Fire, a ship may not perform any Air Operations and suffers one Hit and the loss of two AFs for each turn the fire rages. This damage is assessed at the end of each Combat Phase, beginning with the turn the Fire Starts.
2. Beginning the turn after the Fire starts and each turn thereafter, if it remains unextinguished the player rolls one die just before the Combat Phase. A roll of 1-4 extinguishes the Fire immediately. No damage is assessed that turn.
3. More than one Fire may burn on a ship concurrently. These are treated separately, each causing damage and being extinguished or not individually.
Recommended Optional and Variant Rules
FLAT TOP OPTIONAL RULES
1. All Scenario-Specific optional rules.
2. Additional Planes, both Allied and Japanese
3. Critical Hits – concept only – modified in this Vassal Module
3. Expanded Plane Functions
4. Expanded Ship Functions
JIM DAVIS’ VARIANTS
From “FLIGHT JACKETS NOT INCLUDED Tactical Chrome for FLAT TOP”
1. Revised Combat Modifiers (see the “Optional Tables”)
2. Revised Air-to-Air Combat Modifiers. (see the “Optional Tables”)
3. Revised Critical Hits Tables (see the “Optional Tables”) – modified in this Vassal Module
4. Early Risers – concept incorporated into scenario deployments where relevant.