USS Pyro (AE-1) Class

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USS Pyro (AE-1) circa 1924
Click on this photograph for links to larger images of this class.

Class:        PYRO (AE-1)
Design        Navy AE-1
Displacement (tons):        7,040 light, 11,058 full
Dimensions (feet):        482.75' oa, 460.0' pp x 60.9' wl x 25.4' mx, 20.9' mn
Original Armament:        4-5"/51 2-3"/50
Later armaments:        2-5"/51 4-3"/50 8-20mm (1942: AE-2); 2-5"/51 4-3"/50 2-1.1"Q 8<10-20mm (1942: AE-1, 1943: AE-2)
Complement:        203 (1929: AE-2)
Speed (kts.):        14.7
Propulsion (HP):        6,700
Machinery:        Parsons geared turbines, 2 screws

Construction:

AE	Name	Ord.	Builder	Keel	Launch	Commiss.
1	PYRO	5 Jan 17	NYd Puget Sound	9 Aug 18	16 Dec 19	10 Aug 20
2	NITRO	2 Jul 18	NYd Puget Sound	19 Mar 19	16 Dec 19	1 Apr 21

Disposition:

AE	Name	Decomm.	Strike	Disposal	Fate	MA Sale
1	PYRO	12 Jun 46	3 Jul 46	17 Jul 46	MC/D	20 Aug 48
2	NITRO	30 Nov 45	19 Dec 45	30 Mar 48	MC/D	20 Aug 48

Class Notes:
FY 1917 (AE-1), 1919 (AE-2). The Naval Appropriation Act for FY 1917 that became law on 29 Aug 16 authorized a three-year building program of ten battleships, six battle cruisers, ten scout cruisers, fifty torpedo-boat destroyers, nine fleet submarines, fifty-eight coast submarines, one experimental (Neff) submarine, and two gunboats. To support these combatants it also authorized three fuel ships (oilers), one repair ship, one transport, one hospital ship, two destroyer tenders, one fleet submarine tender, and two ammunition ships. Sixty-six of these ships including one fuel ship, the hospital ship, and Ammunition Ship No. 1 were to be begun during FY 1917, the others were to be funded and begun during the following two fiscal years. Ammunition Ship No. 2 was funded in FY 1919 (Act of 1 Jul 18). Names were assigned to both ships on 31 Mar 19.

The General Board first addressed the question of the best method of replenishing the ammunition supply of the Fleet on 10 Dec 1900. By 24 Mar 09 it had developed a firm concept of fleet auxiliaries for the transportation, in company with the fleet, of coal, ammunition, stores, and facilities for repair and had fixed upon a uniform speed for these auxiliaries of 14 knots with the belief that this would probably be the fastest economical cruising speed of battleships of the latest design. The speed of 14 knots was also an economical rate of speed for vessels of the size proposed for the auxiliaries (the ammunition ship was to have a 6,000 ton carrying capacity) and could be maintained for long periods of time. The Board recommended the allotment to each division of eight battleships and its attendant combatants one store ship and one ammunition ship. It considered carrying both ammunition and stores in one ship but rejected this arrangement because of its complexity. It also rejected the idea of carrying ammunition in colliers, because the type of collier approved was one having its machinery in the stern in order that the bunkers might be continuous, thus facilitating the rapid delivery of coal, and the placing of a magazine among these bunkers would impede this rapid delivery.

On 25 May 11 the Bureau of Ordnance reminded the Department of its view that the Navy needed “an ammunition ship or some auxiliary properly fitted for the transportation of ammunition,” noting that it was necessary to make quite a number of shipments of ammunition, especially target practice ammunition, to vessels of the fleet every year. The majority of such shipments had been made by the collier LEBANON (which had been assigned to duty as an ammunition ship in 1910) and in a few cases by other colliers. None of these was properly fitted for handling and transporting ammunition in that they had no flooding arrangements and no provisions for proper ammunition stowage. Ammunition shipped by colliers had received very rough treatment, with powder tanks and boxes being broken and projectiles arriving in damaged and rusty condition. The Navy had recently had a close call when the supply ship CULGOA, then carrying powder, had been involved in an accident in New York harbor that produced a fire alongside the ship. The General Board on 25 May 1911 concurred with the need for an ammunition ship, included one in its building program for the next year, and provided characteristics for the ship, but as in the previous three years its recommendation for the construction of such a ship was without result. The Bureau of Ordnance on 6 Dec 11 expressed its unofficial opinion that the Navy had a more urgent need for repair ships and supply ships than for ammunition ships and that merchant vessels could readily be converted into ammunition ships without material change at short notice.

In 1913 and 1914 the General Board forwarded to SecNav characteristics for ammunition ships for the 1914, 1915 and 1916 building programs, but in each year other auxiliary types took precedence. On 25 Aug 15 the Board forwarded characteristics common to all fleet auxiliaries (ammunition, fuel, hospital, repair and supply ships, destroyer and submarine tenders, and transports) that might be authorized for FY 1917. These included a speed of 14 knots sustained, a steaming radius of 8,000 miles at 10 knots, and twin screws housed under the stern. On 7 Oct 15 the Board forwarded the special characteristics for ammunition ships. These specified a speed of 16 knots, a departure from the general specifications made in 1915 for the ammunition ship but not for any other auxiliary type. The ship was to have bulk stowage for 3,025 tons of projectiles and charges for 16”, 14”, 12”, 6”, and 5” guns and fixed ammunition for4” guns. The ship's own armament was to be four 5" and four anti-aircraft guns. Her cargo magazines were to be located as far as possible from the ship's sides and well below the waterline. They were to be provided with means to keep them below 80 degrees in temperature and were to have adequate sprinkling, flooding, and draining arrangements. They were also to be arranged to take other general cargo when so desired.

On 2 Aug 16 BuC&R completed and forwarded to SecNav a preliminary design for the FY 1917 ammunition ship based on the General Board's characteristics of 7 Oct 15. The designers began in early July with two alternative sketches, one based on Supply Ship No. 1 and one on Transport No. 1. Both used the 16-knot machinery of Hospital Ship No. 1. The sketch based on the transport was selected because it would save some work in the development of detail plans and would give a vessel having cargo space in excess of requirements which might prove useful. However the machinery was moved aft to avoid breaking up the cargo space and the refrigeration units and to minimize interference with cargo handling gear. Powder was stowed in the hold to give it the best possible protection against gunfire, and oil tanks were fitted between the cargo ammunition and the sides of the ship for additional protection. Refrigerating facilities were increased to permit the use of the ship as a supply ship when not needed to carry ammunition. The General Board approved the design on 23 Aug 16 and SecNav approved it on 31 Aug 16. The preliminary design had the bridge deckhouse on the bow as in the Navy's large colliers and the first two Navy-built oilers of the KANAWHA (AO-1) class, but the ships were completed with it further aft as in the final four ships of the KANAWHA class.

Although the two ships were designed for 16 knots, their trial speeds were listed in the 1929 Ships Data Book as 13.19 (AE-1) and 13.36 knots (AE-2). In the 1935 Data Book their speed was listed as 13.0 designed, and in 1936 AE-2 listed her maximum speed over 24 hours as 14.7 knots. The inter-war Navy needed only one ammunition ship and PYRO was out of commission between 1924 and 1939. A ship's history written by NITRO in 1931 stated that she made an average of three trips each year from the East to the West coast via the Caribbean, moving ammunition and explosives from the various ammunition depots and supplying the Battle Fleet with their target practice ammunition in December of each year. The ship also had a passenger carrying capacity of 10 officers and 250 men in addition to her own complement, and on an average trip between the two coasts this capacity was filled. She also supported forces in Nicaragua, at Pearl Harbor and in the Far East. Both ships were given stronger anti-aircraft armaments in 1942 at the expense of two of their four 5”/51 guns.

Ship Notes:

AE	Name	Notes
1	PYRO	Decomm. 10 Sep 24 at Puget Sound, placed in full commission there 1 Jul 39. Sold by MC to Welding Shipyards for operation under U.S. flag, to buyer 13 Oct 48, buyer defaulted. To National Metal & Steel Corp. for scrap March 1950.
2	NITRO	Sold by MC to Welding Shipyards for operation under U.S. flag, to buyer 14 Oct 48, buyer defaulted. Probably resold as AE-1.