USN Warship Notes

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Battleships

Battleships follow a regular progression of increasing arms with each new class. The number of guns is increased until a limit is reached. When the next larger gun is introduced, the number of turrets is reduced. The number of turrets are increased with subsequent classes, all accompanied by a general increase in ship size to support the larger guns. Armor plate was typically sized to resist an enemy shell of the same sized big gun, thus the weight displacement of the warship continually increased.

Monitors . The success of the Monitor over the Merrimac lead to American adoption of the low freeboard, big gun, coast defense ships that, because of the size of their guns, were classified as battleships. Some other nations also adopted monitors for coast defense. A monitor had no sea keeping qualities and they were eventually superseded by conventional seagoing battleship designs with the Indiana as the US developed an empire as a result of the war with Spain in 1898? A monitor was towed to the Philippines, an unsatisfactory experience. (The original Monitor sank while transiting from Norfolk to Charlestown on 31 Dec 1862.) The last class of US monitors were converted to submarine tenders in WWI where their low freeboard was ideal for submarines to tie up.

Early battleships carried a mix of gun calibers. In 1900 a typical battleship was 15,000 tons, had a main battery of 12" guns, a secondary battery of 6" guns in side turrets, and smaller guns in casements along the sides. As armor made smaller arms less effective, the norm shifted to a mix of 12" and 9" guns. The mix of guns made recognition of the fall of shells difficult and a theory of the superiority of all guns of one size was circulated.

Dreadnought Battleships The South Carolina and Michigan were designed in 1905 as all big gun battleships with 8- 12" guns and commissioned in 1909. Meanwhile England laid down the Dreadnought in Oct 1905 and commissioned in Oct 1906, thus bearing the distinction of being the first and namesake of the new type of battleship. Dreadnought carried ten 12" guns and could stand at maximum range and destroy any battleship of the era that carried only four big guns with many useless lesser armament. All existing battleships were immediately rendered obsolete. Dreadnought also included other improvements, steam turbines, thicker armor that justified the demarcation between "Dreadnought" and "pre-Dreadnought" battleships.
Naval Gun Sizes

Name	Caliber	Millimeters	Weight
.30 caliber	.303	7.62 mm
.50 caliber Browning	.500	12.7 mm
20 mm Oerlikon	0.79	20 mm
1.1 inch Hudson	1.1 in	28 mm
37 mm	1.46 in	37 mm	1 pounder
40 mm Bofors	1.57 in	40 mm	2 pounder
3 pounder	1.85 in	47 mm	3 pounder
4 pounder	2 in	50 mm	4 pounder
6 pounder	2.24 in	57 mm	6 pounder
3"	3 inch	76 mm	12 pounder
5"	5 inch	127 mm	36? pounds
6"	6 inch	152 mm	108 pounds
8"	8 inch	203 mm	240 pounds
12"	12 inch	305 mm	1,070 pounds
14"	14 inch	355.6 mm	1,660 pounds
16"	16 inch	406 mm	2,240 pounds.

Difficulties in Determining Ship Displacement.

• Sources differ, examples:
WW2Weapons.

Class	Haze Gray		Jane's	Battleships
Colorado	32,600 tons	32,600 tons	??	?
North Carolina	35,000 tons	42,000 tons	??
Iowa	45,000 tons	52,000 tons	??
Sangamon CVE-26

Sources of Displacement Confusion.
• Empty Displacement of the ship when launched vs Full Load of arms, fuel, etc.
• American ton is 2,000 pounds. Metric tonne is 2,200 pounds.
• Individual ships may differ from their class; specially a problem when the first, namesake ship differs from the rest of the class. Should one show the namesake's weight, the displacement of the majority, or an average?
• Ships were modified over their lifetimes.
• Different sources are not comparable, each show a displacement without specifying which type of displacement is meant. Their compilers may be equally confused and finally just go with a best-guess number. This is what your web author has to do.

Other things that cause confusion.

• Ship length: measure at the waterline or from stem to stern, and in the case of carriers, flight deck length.
• Launch date vs commission date. The shipyard measures progress from date laid down to date launched. Launch means the ships hull is complete and is floated to free up the shipyard way for the next ship to be laid down. There is still a lot of construction to be done, typically 50% - superstructure, internals, even armament is yet to be added. Commissioning is when the ship is ready to sail and is accepted by the Navy. Then follows a several month long period of assigning and familiarizing personnel, loading of fuel and stores. Trials are the next step in which the ship puts to sea to test everything. The ship returns with the list of things that need to be fixed or improved in another period at the yard. More crew reports aboard for orientation and goes for a training cruise. When the captain thinks his ship is ready, the ship is assigned to a combat arena and proceeds to its new home port. The ships complement is filled out and proceeds with combat training and with joint fleet operating procedures. A review of ship histories shows the time from commissioning to first combat patrol is typically ?? months for battleships, ?? months for fleet carriers. Cruisers and destroyers were not examined.

  Aircraft . The combination of aircraft and radio allowed actively spotting shellfire beyond the line of sight or indirect fire caused quick acceptance by all navies. Scouting aircraft extended the eyes of the fleet over the horizon.
  Aircraft catapults which were first mounted atop gun turrets where the turret was turned into the wind for launching or were mounted amidships were recovery by hoist was easiest. Catapults were later mounted aft to open the arc of fire and to keep the flammable items well aft where a fire is less likely to spread. The squared off stern of wartime designs is to house a hanger.

  Cruisers

  Cruiser designs follow some of the same patterns as battleships, but are much more of a compromise. Battle cruisers carry the big guns of a battleship, though usually fewer, but sacrifice armor for speed. WWI showed a weakness is that they could not stand up to the punishment in a battleship fight or could they project the weight of broadside salvo to reduce the enemy battleships, and were too slow to chase down enemy cruisers. So, by definition, any cruiser is a design compromise between firepower, armor, and speed.  Treaty limitations also impacted designs built before the war that were actively engaged during the War. Treaty defined a light cruiser as carrying 6" guns and proscribed a heavy cruiser to have a maximum of 8" guns. Both were limited to 10,000 tons of maximum weight and each nation had a maximum total weight of all ships. Thus we can find some American heavy cruisers with light armor to keep under the individual ship limits and also to allow building more cruisers and still stay within the national total weight limit. Ship design is a compromise of armament, armor, range and speed. As weight goes up, speed goes down, requiring bigger engines which increase weight and consume more fuel, reducing range. An examination shows a consistent design speed of US cruisers; all rigorously follow treaty weight limits; (Japan exceeded the limits and lied about it.); armament and armor were the major tradeoffs.

  Designs tried to meet the needs foreseen. This is most obvious in national designs. German ships sallied for short trips and did not need to provide much for crew accommodations. Japan considered armament the reason for warships and carried lots of guns, but were uninhabitable by US standards. US ships were designed for temperate climates and did not include sufficient air circulation for equatorial weather; surprise torpedo attacks were devastating when all passage ways were open to allow cooling. Britain liked light cruisers to patrol her shipping lanes where there were many close ports of call. The US felt a need for range and heavy guns to operate in the vast Pacific, hence maintained a larger proportion of light weight, heavy (8") cruisers than other nations. Once the size limitations were removed, the US started building the Baltimore class of larger heavy cruiser, but was most successful in quickly producing large numbers of Cleveland class light cruisers.

  Convoy System

  With insufficient escort warships to escort each merchant ship, it is natural for several merchantmen to congregate around the available warships. The convoy system was instituted in the Atlantic by [date] to allow a few anti-submarine escorts to circle a significant number of ships. This made attack by submarine more difficult and dangerous. The U-boats responded with wolf pack tactics to overwhelm the defenses. Improvements in radar, sonar, radio tracking and weapons like hedgehog and longer range air cover eventually defeated the wolf packs.

  The Germans also sent cruisers to attack the convoys; cruisers outgunned the light arms of the convoy anti-submarine escorts and the cruiser easily ran down the scattering convoy. The convoys then had to employ defending cruisers. The Germans responded with the battleship-cruiser combination wherein the battleship engaged the convoy escort while the cruiser shelled the merchants. An aircraft carrier tried to accompany each troop convoy. Later in the war, there were sufficient escort carriers (CVE) to accompany most convoys and even go off in search of submarines traveling and resting outside of the convoy lanes so that U-boats were under attack everywhere.

  It was partially in anticipation of convoy raiders (convoys and raiders were also used in WWI) that in 1940 the US authorized battle cruisers - to defend shipping by outgunning conventional cruiser-raiders with less expense and more speed than battleships. However, the Japanese did not raid convoys with surface ships, nor did they convoy their own merchant ships, making attack by US submarines more advantageous.

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  Last updated: November 12, 2001.
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