How-to-Springsharp Guide/Engines

### Number of Shafts

Springsharp makes no distinction between configurations of two or more shafts. However, for reference; two and four shaft configurations are commonplace; three-shaft is hydrodynamically and structurally less efficient but has the advantage of only needing three drive units and being able to mount a singular centreline drive unit for cruising.

## Engines

### Fuel Sources

#### Coal Fired Boilers

**Coal Fired Boilers** are the default before the turn of the century and common thereafter. Coal takes more space than oil due to lower energy density, in addition to requiring many stokers and trimmers. Due to this, in long engagement fatigue reduces the supply to the boilers and results in a reduction in speed over time. Coal-firing produces large amounts of black smoke, which is detrimental to visibility. However, large amounts of coal can provide additional protection to a ship, supplementing the armour protection. Additionally, all coal-firing ships can lay smokescreens by increasing the amount of coal-smoke generated. This smoke is hot and tends to rise, and therefore the resultant smokescreens are fairly short-lived compared to chemical smokescreens.

#### Oil Fired Boilers

**Oil Fired Boilers** are the most common power source between 1905 and 1945 because of the superior energy density to coal, but make sure your nation has an adequate supplies before making your fleet depend on it.

#### Petrol Motors

**Petrol Motors** use for gasoline powered ships, which is most common on submarines. Nowadays it is often used with Diesel, but Springsharp won't accept that as a power source.

#### Batteries

Battery power is most common as a supplement and on submarines.

### Shaft Connections

#### Direct

**Direct Drives** are the default before the turn of the century and common thereafter. Direct drive is especially ill-suited to steam turbines, as turbines are highly inefficient at low speeds, and early direct-drive steam turbines are inferior to reciprocating engines.

#### Geared

**Geared Drives** start appearing in the first decade of the 20th century on smaller designs and their use rapidly increased. The precision machine tools to make reduction gears is a major bottleneck in ship production, and responsible for some of the odder choices in power plants at the end of WW2.

#### Electric

**Turbo-Electric transmission** transfers power from the boilers to the propellers via turbogenerators, cabling, and electric motor. It went in and out of favor depending on the nation and year. The US built a some turbo-electric ships circa 1920. Britain built a few between 1927 and 1931. France built one in 1931. Germany built a few in the mid 30s.

**Diesel-Electric** operates similarly, but with Diesel motors providing the power. It was first proposed for Submarines, but is nowadays common on most ships.

Electric transmission is required in any ship operating with only batteries.

#### Hydraulic

**Hydraulic Drives** operate on the same principles as your car's power steering system does. They are most common on german designs in the early 20th century due to the german gear-cutting industry being unable to meet demand for geared drive systems.

## Weights

### Engine Factor

**Engine Factor** is the option which would let one design ships with more lightly constructed engines, including most light cruisers and nearly all destroyers; sadly it is yet unimplemented.

### Range

A ship's **range** is how far it can go without refueling, and depends on the ship's Cruise Speed set above. Remember that this includes any reserve fuel, so if a ship needs to be able to go 4000 nautical miles, then it's safer to give the ship a range of 4400 nautical miles. Lastly, the fuel needed for any given range goes up quickly as speed goes up. A ship will likely be able to go about twice as far if it goes five knots slower.

### % Coal

A ship's **Percent Coal** will be 100% if the ship's only fuel source is Coal, and zero if coal isn't a fuel source. Sprayed Coal is generally 80 to 90% coal. If a ship has a coal bunker as part of its armor scheme – as some interwar French designs did – include coal as a power source above, then make sure the ship's range is great enough that it can go the desired distance on its non-coal fuel sources.

## More Info

https://en.wikipedia.org/wiki/Marine\_propulsion