From: You May Fire When Ready Gridley: Rules for Pre-Dreadnought Naval Wargames, 1880 to 1900 and Beyond, Edition 1.1 by David Manley (Garden Grove, California: Brookhurst Hobbies, 2000), page. 27.

15.1 – Coaling and Coal Consumption

Coal Capacities

Ships have a defined bunker capacity. Jane’s gives bunker capacities for many warships which should be used where available, but in the absence of any hard and fast data assume the bunker capacities shown on the table below:

Ship Type	% of standard displacement
British and French built battleships	6 – 10%
British and French built cruisers	10 – 14%
Other nations’ battleships	5%
Other nations’ cruisers	7 – 10%
Destroyers	10 – 20%

British and French ships tended to be designed for world-wide operations, whereas many other navies employed ships for local or regional operations only, where extended range was not so necessary.

Coal Consumptions

Each day, ships use coal at the following rates:

· At sea, cruising 1% of displacement per day

· At sea, max. speed 5% of displacement per day

· At harbor stations 0.33% of displacement per day

- if at 2 hours notice for sea

· At harbor stations 0.25% of displacement per day

- if at 4 hours notice for sea

· At harbor stations 0.10% of displacement per day

- if at 6 hours notice for sea

Ships that exhaust their coal supply must anchor and await a refueling collier. They are assumed to have sufficient reserves of coal to keep essential systems operating, but are unable to move or operate powered turrets.

Coaling is a ‘whole ship evolution’; i.e. all hands muck in. It also requires the vessel to be in harbor, anchored in sheltered waters or hove o in calm seas. It takes 1 hour to prepare the ship for coaling (opening up shipping routes, mustering crew etc.). Following this the ship can take on 10% of its total fuel capacity in tons per hour. At the end of the coaling it takes a further hour to close the ship up again and secure from coaling stations, prior to being ready for sea or for action. Coaling whilst hove to is a slower evolution, with coal transferred at 5% of capacity per hour.

Example. The MIKASA is alongside having expended 40% of her coal. Opening up takes 1 hour, 4 hours are spent coaling, and 1 hour spent closing the ship up again, for a total of 6 hours. If this had been attempted whilst at hove to the task would have taken 1+8+1=10 hours.

Colliers are available to supply ships at sea and on deployment. A collier’s coal capacity is expressed in terms of the tonnage of coal it is ale to carry, and will generally be the “tonnage” of the ship if this is known. (“Tonnage” for a merchant ship generally refers to its cargo carrying capacity rather than the weight of the whole ship.)

Overload

Ships often deployed with excessive amounts of coal on board. Typical examples were the Russian fleet heading for Tsushima., and most US battleships. Whilst overloading increased endurance it reduced stability, freeboard and often submerged the armored belt. Ships may carry excess coal up to the limits stated in Jane’s or other references, or up to 100% excess if no other data is available. While carrying excess coal (regardless of the amount) belt armor is reduced by 3 levels (e.g. from 2A to C), and BDV is reduced by 25%.

Optional Rule: Coal Quality.

Certain grades of coal were of poor quality. Conversely, other grades (such as Welsh coal) were of a particularly high quality. If non-standard coal is used it will have an associated Fuel Use Multiplier, typically 1.1 to 1.5 for poor grades, 0.95 to 0.85 for high grade. This results in fuel being used at an accelerated or decelerated rate. For example, a battleship with a cruising consumption of 100 tons per day uses poor quality German Ruhr coal (multiplier 1.1) and so uses 110 tons per day. The same ship later restocks with high quality Welsh anthracite (multiplier 0.85) and so only uses 85 tons per day.