Proposal to Improve Historical Accuracy of Engine Shaft Techs

[BattleshipOfDestruction]

This topic is to discuss an improvement to the generic, nonsensical and immersion breaking shaft types in the game. More topics will be coming about other modules and discussions on their accuracy and possible improvements that can be made.  Also please note, and this applies retroactively to all other topics previously posted, if you see 1950 as an ending year it signifies the end of the campaign so these components would be available until the end of the campaign.

Essentially all the Engine Shaft Techs in the game are weirdly generic; with no explanation other than each is "advanced" with its own tier to denote there were improvements. Although materials improved and engine shafts became more durable to the rigors of damage, it did not mean that these shafts were indestructible, neither did it provide the same bonuses as the vanilla options. Therefore I would rename this section to "Engine Shaft and Propeller Configuration" in-game to be more inline with historical precedent, and add options that were actually present during the time periods. Below are said enhancements to this section:

At Tier I we have a Double Shaft Design with Triple Bladed Screws (2 Shafts with 3 Bladed propellers). This becomes available in 1890 and is available in game until 1900. Before the 1890s, sail and screw-driven steam battleships and ironclads used a single shaft with 2-4 blade propellers. The single shaft was inefficient and resulted in wasted potential energy and lower overall top speeds. The 1890s saw the introduction of two-shaft systems, requiring two sets of piston engine components and boilers for each screw. This increased weight but significantly improved speed and allowed for better ship maneuverability by allowing for powered steering. The engine orders could be independent per shaft which allowed one shaft to be reversed while continuing at full throttle for the other shaft to greatly increase rate of turn and lowering the overall turning circle accordingly. Experiments in the 1870s and 1880s determined that the triple-bladed screw propeller was the most efficient design, offering a balance between reducing vibrations and engine power efficiency.

Preliminary Values:

Hull Weight: 0%

Armor Weight: -10%

Hull Cost: 2.5%

Max Speed Penalty (From Engine Damage): -10%

Acceleration: 15%

Turning Rate: 10%

Fuel Efficiency: 10%

Engine Vibrations: -20%

 

At Tier II we have the Triple Shaft Design with Triple Bladed Screws (3 Shafts with 3 Bladed Propellers). This becomes available in 1892 and remains available in game until 1935. Introduced in 1892 on the French Pre-Dreadnought Battleship Masséna, it was the first warship equipped with three shafts. This design, typically using 3-bladed propellers, saved space and weight compared to later 4-shaft designs, allowing for a narrower stern and less material for armor and torpedo defense. Three propellers were slightly more fuel-efficient than two, but were less power efficient. Due to the fact that the third shaft would interfere, powered steering was not available in triple shaft configurations. Three shafts also made the stern area weaker around the middle shaft which could become a problem if a torpedo or shell were to impact that area. Initially, the three propeller shafts rotated in the same direction, causing cavitation and vibration. Later, the central propeller was pitched to move water in the same direction as the outboard set, while rotating in the opposite direction to mitigate this. Despite being less power-efficient, the Germans favored this configuration, even using it in the Bismarck class during WWII to avoid the width restrictions of the Kiel Canal. Some H-Class proposals considered 4 shafts, recognizing the drawbacks of the 3-shaft design, despite never being constructed.

Preliminary Values:

Hull Weight: 5%

Armor Weight: -5%

Hull Cost: 5%

Max Speed Penalty (From Engine Damage): -15%

Acceleration: 20%

Turning Rate: 0%

Fuel Efficiency: 15%

Engine Vibrations: -10%

 

At Tier III we have the Quadruple Shaft Design with Triple Bladed Screws (4 Shafts with 3 Bladed Propellers). This becomes available in 1905 and is available in game until 1945. Starting with HMS Dreadnought in 1905, warships increasingly used 4 shafts which typically used triple bladed propellers at this stage. Four shafts didn't always mean four engines as the introduction of turbines introduced one set of main turbines for ahead and astern applied to two shafts, improving efficiency and power output. Quadruple shafts were more efficient than other configurations due to better propeller interactions with the sea, reducing engine noise and cavitation. The even number of shafts also enhanced engine-assisted steering and improved acceleration. However, this design required a wider stern, which necessitated more armor and anti-torpedo material, but in return had a stronger stern that wasn't as vulnerable to shell or torpedo hits.

Preliminary Values:

Hull Weight: 10%

Armor Weight: 0%

Hull Cost: 7.5%

Max Speed Penalty (From Engine Damage): -30%

Acceleration: 25%

Turning Rate: 20%

Fuel Efficiency: 20%

Engine Vibrations: -25%

 

At Tier IV we have the Quadruple Shaft Design with Quadruple Bladed Screws (4 Shafts with 4 Bladed Propellers). This Becomes Available in 1935 and is available in game until 1945. First introduced on the French Battleship Strasbourg of the Dunkerque Class in 1934, quadruple-bladed propellers offered superior acceleration and maneuvering power, with decreased vibrations due to lower cavitation compared to three-bladed screws. However, in a four-screw arrangement, the perceived acceleration boost was minimal. Additionally the outboard shafts interfered with the inboard shafts which caused more engine vibrations and cavitation than the previous technology.

Preliminary Values:

Hull Weight: 12.5%

Armor Weight: 2.5%

Hull Cost: 10%

Max Speed Penalty (From Engine Damage): -35%

Acceleration: 30%

Turning Rate: 30%

Fuel Efficiency: 25%

Engine Vibrations: -15%

 

At Tier V we have the Quadruple Shaft Design with Mixed Blade Configuration (4 Shafts with 4 Bladed Propellers on the Outboard Set and 5 Bladed Propellers on the inboard set). This Becomes available in 1940 and available until 1950 (campaign end).  Five-bladed propellers saw limited use during WWII but were rarely used exclusively until postwar. Due to the underwhelming performance of the four-bladed, four-shaft design, a hybrid design was adopted for the Iowa Class Battleships, laid down in 1940. This design used quadruple-bladed propellers on the outboard set and quintuple-bladed propellers on the inboard set further aft. The extra blade on the inboard set reduced cavitation and engine vibrations, improving acceleration, fuel efficiency, and maneuverability. The SS United States, (a distant ocean liner cousin of the Iowa Class) utilizing this propeller configuration, achieved a top speed of 38 knots (44mph), winning the Blue Riband for the fastest ocean crossing, a record it still holds. Unfortunately, SS United States is slated to be sunk as an artificial reef in 18 months; following its purchase by Okaloosa County, Florida in October of 2024.

Preliminary Values:

Hull Weight: 15%

Armor Weight: 5%

Hull Cost: 12.5%

Max Speed Penalty (From Engine Damage): -40%

Acceleration: 50%

Turning Rate: 40%

Fuel Efficiency: 40%

Engine Vibrations: -40%