House Rules for Cruel Seas

I've been musing on some house rules for "Cruel Seas" since they came out. The errata does a good job of clearing up mistakes in the rules, but there are some areas where I feel the rules lacked authenticity, and so could be "house ruled" for added realism without adding to the complexity of the game. Here's what I've come up with so far. I'd be keen to hear from anyone else who has thought about this.

1. Turning – The rule that only allows craft to turn after each 1/3 of maximum speed leads to some daft situations where  a tanker at full speed can outturn an MTB or S Boat at the same speed simply because the tanker is at Full Speed (so it gets 3 turns) and the small craft only one (because they are at Slow). To create a better turning model vessels can execute a turn after each 1/3 of their movement for the turn rather than their maximum movement. So, a Vosper travelling at Combat Speed (24) can turn after 8, 16 and 24. 

2. Large ship manoeuvrability - Large and Huge craft are still too manoeuvrable using this system, so only allow Large ships to turn twice (after each half of movement) and Huge craft once (after all movement is completed). In addition, consider changing warships in each group to Red rather than Yellow to give them enhanced manoeuvrability over merchant ships and more barge-like vessels (I've not had a chance to test this much but it feels right)

3. Turning on the spot - Large and Huge craft that are stationary have amazing turning ability, way beyond anything that is physically possible (medium and smaller craft would be able to make decent turns through applying full power for a few seconds to bring the boat’s head around – effectively a short forward movement and turn, but for the purposes of the game a turn on the spot is OK). But Large and Huge ships are only allowed one turn at the Red or Yellow angle as appropriate to the ship.

4. Minimum ranges. In addition to the minimum ranges listed set the minimum range for S Boat bow 20mm guns to 10cm. These guns were noted for having a very limited ability to depress to engage close targets, whereas the S Boat’s other guns were generally on open deck mounts and could.

5. Torpedo management - Treat all torpedoes as “orphaned” but give all torpedoes an activation die of their own. When its drawn - all torpedoes move. This removes the need to remember who launched what, but keeps the random factor of exactly when they move in the game. Also give them unlimited range. They keep going until they exit the table. Torpedo running distances were way beyond the fighting area covered in a typical game using these rules.

6. Damage table – The majority of guns listed in the table are “automatic” so delete the “semi automatic” modifier. Instead, increase 6pdr damage to 6D6, and use the 5D6 6pdr line for manual guns (e.g. the aft gun with the shield on the Fairmile D model). Similarly, reduce damage from single shot versions of 37mm and 40mm guns (e.g. 2pdr anti tank guns used on Partisan ships in the Adriatic) by 1D6

7. Splashes - Ignore rules for splashes. The rule doesn’t have any basis in fact, as incoming fire might draw attention of other ships onto a target, but isn’t going to help them aim.

8. Damage table – delete line for quad guns, replace with “Triple or quad Guns +2D6”. Quads were used because the effective ROF of the 20mm was quite low; the sustained ROF of the flakvierling was similar to the twin 20mm Oerlikon)

9. Critical Damage Table - The table as it is works fine for small craft but not for larger ships (is all fire from a destroyer or monitor going to stop because a 20mm gun scores a critical?). To better apply the results of the table ignore critical hits 1, 3, 4, 6 in Large or Huge steel ships unless caused by 4” guns or larger.

10. Armour – The S-100 armoured bridge (and other armoured locations in other craft) was only effective against LMG and HMG, with a chance of deflecting 20mm HE rounds. So allow full effect against HMG fore, a 50% chance of deflecting 20mm (roll a D6, penetrates on a 4+), and no effect vs. 37mm or larger.

11. Strike the flag – This rule is pretty meaningless as it stands. It was also quite rare for ships and boats to strike their colours and cases where boats were captured invariably occurred when the craft had been crippled. So instead I’d suggest that, where a craft reaches 0 points or lower the craft has become wrecked. Rather than sinking it remains on the table but cannot move or fire. Note any excess damage caused, this becomes a 2D6 roll at the start of each turn to see if the craft sinks (for example, a craft suffers enough damage to put it on -5, so each turn roll 2D6 and if the score is 5 or less the craft sinks). Survivors can be rescued from the craft until it sinks. Conversely an enemy may attempt to board and capture the craft, which is achieved by stopping adjacent to the wreck and, on the next activation, rolling ABOVE the excess damage (so in the example the craft would be boarded and captured on a 2D6 roll of 6 or more. Again, roll in the boarding craft’s activation. The crew of the wrecked vessel may attempt to scuttle the craft each turn when activated, before the sinking test is made; roll a D6 and add the score to the excess damage.

12. Visibility – a better representation of visibility at night is needed to capture the feel of a coastal forces battle. To keep things simple for night actions set maximum visibility unaided at 100cm, at 50-75cm if you want to fight in very dark or gloomy conditions. Add 10cm to spotting distances for craft that are travelling at greater than 20 knots / cm, 20cm for craft at greater than 30 knots/cm. Replace the models with markers for craft that are out of visibility. Craft are placed on the table when they move into visibility range. Illuminated craft (e.g. craft targeted by or using searchlights, craft on fire, craft illuminated by starshells) can be seen and engaged at any range – unless you have decided that the playing area is affected by mist or fog, in which case the maximum visibility is just that, and nobody can see or engage a target at greater distances whether they are illuminated or not.

13. Searchlights – The rules as currently written completely fail to capture the way searchlights work and the way they were used in WW2 navies. As in the rules they can illuminate a target out to 100cm that has been spotted by the craft using the searchlight or detected by that craft using radar. Both the target AND the vessel using the searchlight are Illuminated. Any fire at the illuminating craft or the target it is illuminating gain the +1 modifier to incoming fire

14. Mines – There are some issues in the mine rules. The errata adds the mine table that was missing. But the way that pressure mines work runs counter to their actual effects (a craft’s pressure signature being smaller at low speed rather than high). In this case change the Skill Test so that it applies to Small craft, Medium craft and Shallow Draft vessels at 10 knots or less.

15. Exotic Weapons - The list of “exotic weapons” has a very German feel about it. To even things up a bit allow RN MTBs and MGBs to use the Holman Projector (this was an anti aircraft grenade thrower that was fitted to most RN coastal forces craft). Treat the Holman Projector as the PAC / Drahtseilrakete but it has no risk of causing damage to the craft that uses it.

16. Air attacks – It is curious that the rules don’t allow aircraft to make strafing attacks when this style of attack was the primary mode of damage to PTs, MTBs and S Boats from aircraft. The rules as written actually seem to suggest that a strafing rule was there in an early draft but was deleted for reasons unknown. To give aircraft more purpose and threat in the game allow them to conduct strafing attacks against one vessel that they pass over during movement. These are treat as normal machine gun or cannon attack, ignore the -2 modifier for speed of shooter and the +2 for point blank range (they just cancel each other out). Apply the damage bonus for the number of guns firing up to a maximum of +3D6 (for example, a Spitfire shooting eight .303 machine guns hits and rolls a basic 1D6 plus 3D6 for 4 or more barrels firing). Unlike shots from sea level, LMG hits from aircraft CAN cause criticals.

16a. For added complexity allow turret and pivot machine guns on aircraft to engage targets within 30cm of their line of flight. If the aircraft does NOT pass over the target the -2 modifier for aircraft speed plus the relevant range modifier are applied.

17. Torpedo reloads. Several craft are listed as having torpedo reloads, but there are no rules on how long or in what circumstances they can be reloaded. The "book" time for an S Boat reload was 45 seconds, but this was in ideal circumstances. Wartime reports indicate that 5 minutes was more common, but that some boat commanders preferred not to carry reloads because the opportunity to reload the tubes was rare and the evolution was a long one. To reflect this one torpedo can be reloaded at the end of a turn if the following criteria are met:

• The boat is at Slow speed
• The boat does not make any turns during its movement
• The boat does not fire any weapons
• The boat is not itself under fire
• The boat crew make a successful skill test, with a +1 modifier (so Veteran crews succeed on a 3+)

18. Repairs. The rules for repairs seem a bit optimistic, especially as it is possible to repair a boat to its pristine condition. I would suggest the following additional aspects to repairs. (1) the number of damage points that can be repaired is 50% of the damage caused. So a boat that has taken 10 points of damage can repair up to 5. (2) repairs require personnel to do the work, which is likely to need all hands (or at least extra hands) to effect. This will limit the number of weapon mounts that can be used whilst making repairs. Small and Medium craft are limited to one weapon, Large are limited to 2, Huge are limited to 3.

19. Opportunities to repair Tiny craft are limited, therefore these craft may not conduct repairs.

20. German and Italian Explosive Boats. As the text states these were piloted by a single crewman who jumped overboard once the craft was set on its attack run. This of course means that the crewmen, having jumped, will be swimming and awaiting rescue. Place a marker representing the swimmer at the starting point of the craft's movement in the turn where it impacts a target. Use the rules in Scenario 3 ("To The Rescue") to resolve attempts at rescue.

21. Shooter Speed Modifiers in Gunnery. Ships at "full speed" have a -2 modifier. Because of this a trawler plodding along at 12 knots presents a less stable gun platform than a torpedo boat at 24. Another feature of the division of speed into three brackets without really considering what those brackets mean for each type. There are a number of ways to approach this, here is my recommended one:

• Shooting vessel is Fast AND shooter is Tiny, Small or Medium AND speed >20 : -2
• Shooting vessel is Stopped AND is Tiny, Small or Medium : -1

The rationale for the "stopped" modifier is that small craft in articular when stopped wold be affected by any kind of wave action and so may "wallow", something that would not affect larger craft except in higher sea states.

22. Torpedo Damage - there is a LOT wrong with the way torpedo damage is modelled if you were looking for some kind of authentic solution, the system in the rules as written being very much "game" orientated. For my thoughts on this see my later blog entry here