Update 1.0.6.9/Dev Blog 15 - Amphibious Warfare Rework

We’re back with a combined update/dev-blog featuring a series of new mechanics developed for Operation Sea Lion that greatly enhance broader CAOS amphibious combat gameplay, editor additions, and UK 1943 OB expansions.

The first half of these update notes double as a CAOS Amphibious Warfare Overhaul dev blog. Fair warning, it gets table heavy and deeply nerdy. The second half tackles the more routine aspects of the update.

Amphibious Combat Overhaul:

The amphibious combat system has been totally overhauled to reflect the extreme difficulty of amphibious operations and differences in capability, doctrine, and naval fire at the national and equipment level. Each country now receives its own amphibious assault modifier tied to year, naval barrage/fire support is now directly derived from specific ship types, and every equipment type in the game has its own amphibious combat modifier.

Modding: All of the modifiers below can be easily modded in the naval_support, amphib, and wep, inis inside the game files.

Amphibious Equipment Modifiers:

Amphibious equipment modifiers are derived from three essential questions: 1) How will the soldiers reach the beach? 2) Do they have specialist training and doctrine for amphibian operations. 3) Does their equipment give them some unique advantage or penalty?

All weapon types suffer severe amphibious combat penalties, but these can be reduced or completely overcome through various modifiers. Amphibious tractors that can deliver combat personnel directly into combat such as the LVT-2 provide the best bonuses, but any kind of landing ship that can run directly up on a beach helps. Armored vehicles use a similar model, which generally favors swimming tanks, but bottom crawling tanks still enjoy benefits. Doctrine is split into four categories (from highest to lowest), marine-commandos, marines, commandos, and naval infantry. Finally, vehicle size and weight plays a decisive role; it should come as no surprise that you really should not include King Tigers in an assault landing force. Amphib modifiers can be viewed on any weapon card; they are currently listed under the Support header, pending a re-organization of the graphic itself.

See the table below for generalized examples of the new system, combined with UK 1944 national modifiers as a benchmark.

Now, let's see the same table from the German perspective:

National Amphibious Landing Modifiers:

Each nation receives a global amphibious combat modifier, tied to year, that reflects all aspects of a country's ability to wage amphibious operations not already reflected by the equipment modifiers detailed further below. This national amphibious modifier is derived from a nation’s: 1) Joint air-land-sea planning capabilities. 2) Logistical capability to support landings. 3) Experience conducting opposed landing operations. Unsurprisingly, the dominant naval powers enjoy substantial amphibious combat advantages. For instance, the US and UK enter the war with +10% amphibious assault modifiers, and their modifiers rise to an imposing +40% by 1945. Conversely, Germany enters the war with a -10% amphibious penalty, and rises to a +10% bonus in 1941. See the table for details below, by nation.

National Naval Fire:

Direct naval fire support and pre-invasion naval barrage is now modeled by nation, by ship-type. Each naval fire support or barrage mission rolls on a table to select what type of ship is servicing the fire mission. Naval support missions utilize destroyers and light cruisers (sometimes gunboats for Germany and the USSR), while naval barrage selects anything from destroyers to heavy cruisers. The chance of each vessel type being selected for the fire mission are not equal. Larger ships such as CAs, or rare/unique ships such as the German Emden CL, are less likely to make an appearance. The tables below display a sample of ship types, some countries, particularly the UK, have far more sub-types than can be displayed here.

The system does not currently let you micromanage what ship types cover what landings, but if we ever extend this system to include capital ships then a manual selection system akin to the air orders button will likely be implemented.

Broad outcomes: Larger hulls do not necessarily correlate to better naval fire performance in support of amphibious operations. Indeed, the best performers in the current destroyer/cruiser dataset are Cleveland class CLs, and their even more terrifying Brooklyn class siblings, due to their substantial rate of fire advantages over heavy cruisers armed with 8" guns.

As two of the world's dominant naval powers, it's little surprise that the United States and Great Britain generally dominate the naval fire charts. Within the destroyer/cruiser dataset we base these calculations on the US enjoys superiority due to the outstanding performance of their modern 5 and 6" guns. British naval fire can be formidable, but it is inconsistent. Britain's 15" armed monitors are potent and their Town class CLs are excellent. Yet, their DD support is brutally average and some of the other British light cruiser classes (Didos/Bellonas, specifically) fail to impress. Most of these deficiencies are budgetary in origin, owing either to ships continuing to use old weapons, or never receiving their full allocation of guns, or both. Still, even on the Royal Navy's worst day, they outperform Italy, France, the USSR, and unlike the Germans they will never have to rely on a patrol gunboat...

The Kriegsmarine performs admirably...when they actually show up. German naval fire does not reach potential heights of the Anglo-American maritime powers, but they stand firmly ahead of the other continental states due to relatively high rates of fire and solid weapon design. However, Germany falls flat in employment and thin reserves. In the case of Operation Sealion planning for instance, fire support consisted of converted patrol vessels and armed barges due to the combined factors of low ship availability (the Kriegsmarine had 10 destroyers ready for action in the English channel in late September 1940) and poor interservice cooperation between the Kriesgmarine and the Heer/Luftwaffe. In gameplay terms this means German landings either enjoy competent support, or worthless barges, and you will not know which you are getting until you hit the beach.

France and Italy suffer from different naval fire deficiencies that lead to very similar outcomes. Italian naval gun design favors excessively high velocity, necessitating short barrel lives and thick shell walls that leaves less room for explosive filler. Consider for instance, that the 152/53 M1929 cannon carried by most of the Condottieri family of CLs (Cadorna, Montecuccoli, etc.) carries HE shells containing 2.3kgs of explosives, compared to 3.3kgs on average in 5"/38s carried by most US destroyers. 5"/38s further boast substantially higher rates of fire. Consequently, for the purposes of naval barrage and fire support, Italian CLs are routinely outperformed by ships weighing 1/3 their displacement.

French guns on the other hand employ perfectly adequate bursting charges, but suffer from chronically low rates of fire, due to the age of the designs or sometimes defects in more modern designs. While neither France nor Italy play German gunboat roulette, their average naval fire rolls are still well below Germany and in the DD category, even below the Soviets.

Purges, industrial inefficiency, and the pressing need to prioritize land and air forces, left the Soviet Navy woefully underprepared for war. The Chapeyev class CLs were not finished before Operation Barbarossa commenced, and the Kirovs suffered from rates of fire far below design specifications. Consequently, the Soviets lack effective cruiser support, their destroyers are respectable, and sometimes invasion support ends up in the hands of ships that have no business being anywhere near an active landing zone.

Order of Battle Updates:

This update brings UK 1943 up to a modern CAOS standard, with a slight expansion of the OB, including the flexible 2nd New Zealand Division, 2nd tier line of communication units, and various minor corrections for historical accuracy. 1943 is actually a relatively stable year for the UK; it lacks both the desperate improvisation of the war's early years, or the rapid adaptations to combat in continental Europe that the Commonwealth armies will undergo in 1944.

UK 1943:

• Added 2nd New Zealand Division in its September, 1943 order of battle. Complete with the freshly raised 4th New Zealand Armoured Brigade and Staghound heavy armoured cars.
• Added the 3rd Infantry Division, a formerly veteran division stripped of its battle hardened personnel and relegated to Home Defense.
• Added the 227th Independent Infantry and 25th Indian Infantry Brigades as independent units.
• Added Y (17/6pdr) and Z (M10 Wolverine) batteries to 21st Anti-Tank Regiment.
• Converted 146th Field Regiment RA and 13th Royal Horse Artillery Regiments to their Tunisian Campaign OBs using towed 25pdrs instead of SPGs.
• 61st, 64th, and 81st Anti-Tank Regiments received partial batteries of 17pdrs.
• 52nd Anti-Tank Regiment expanded to 5 batteries and received a handful of 17pdrs.
• 3rd Anti-Tank Regiment, RCA brought up to full strength (each battery was previously missing 1 troop).
• Added the 87th and 93rd Anti-Tank Regiments, with 3 and 4 batteries, respectively.
• Removed erroneous 4th battery from the 105th Anti-Tank Regiment.
• 69th Medium Regiment weapons corrected from 5.5 to 4.5” Guns.
• Added the 75th Medium Regiment, equipped with 5.5” Guns.
• Reduced training level of British AA units to recruit.
• Added historical battery names to all Royal Artillery units.

Editor Updates:

• Added support for asymmetric victory conditions in custom scenarios. For instance, you could set Red to require 70% of VPs to win, but only 50% for Blue.
• Added support for historical dates in custom scenarios.
• Custom scenarios can now be created without any units pre-deployed on map on turn 1.
• Unit availability in requisition pool can now be time-gated in custom scenarios. Use this to deny access to specific units until a certain date.

Bug Fixes/Changes:

• Fixed the infamous ultra-wide resolution screen tearing bug caused by opening regiment cards or issuing orders.
• Fixed a bug that could unit pool to become unopenable after loading a save during a preturn after turn 1.
• Fixed a bug that caused the requisition screen to draw over the multiplayer ready screen in custom scenarios.
• Fixed a bug that could duplicate the host player’s requisition points during reinforcement turns in head to head custom games.

Operation Sea Lion Development Status:

That wraps it up for today's dev blog and update notes combo! Operation Sea Lion development has also led to the creation to code support for air mobile divisions, contestable port lines of supply, and many other cool features we'll be rolling out into the base game once they are stable. Broader Operation Sea Lion development itself is currently experiencing an AI development bottleneck, because it requires effectively totally overhauling the the AI to handle scenarios that are far larger than anything the base CAOS was designed to handle. That said, even if it takes a while, general AI improvements are a welcome improvement to CAOS as a whole.