The General Board was sufficiently happy with the `thousand tonner' design to put it ford for the 1913 progamme. But the ring tribes among professional destroyer officers were not so happy; some thought the `thousand tonncrs' were too big and others wanted a heav­ier torpcdo-armament.The Naval College supported an increase to the massive armament of four triple torpedo tubes in beam positions and reloads. The Board refused to countenance such an extreme position, and accepted a Bureau of Ordnance compromise: the addition of two torpedo tubes, a change to the much more powerful 21in torpedo, and eliminating one of the 4in guns. The Board incorporated the new scale of armament in the next group of 'thousand tonners', the O'Briens (DD-51-56).

More attention was being paid to machinery improvements. For the last group of Cassins, Cramp proposed a two-shaft turbine installation, with reciprocating engines for cruising. The change required an altered stern, and the Aylwin (DD-47) failed to make her designed speed on trials. One of the slightly improved Tucker class, the Wadsworth (DD-6U) was the first US Navy destroyer with main turbines geared to the propeller shafts. Unfortunately, she only made only 30.7kts on a trials displacement of ] 05O tons in July 1915, but 326 tons of oil fijel drove her for 5640 nautical miles at 16kts.Thc Cassin (DD-43), Cummings (DD-44), McDouQal (DD-54) and Ericsson (DD-56) each had a reciprocating engine that could be clutched to one shaft for cruis­ing below 15kts.The Tucker (DD-57), CorrynRham (DD-58), Porter (DD-59), JacobJones (DD-61), Wainwright (DD-62), Allen (DD-66), Wilkes (17D-67) and Shaw (DD-68) differed in having a single cruising turbine geared to one shaft.The remainder had a more symmetrical arrangement, with two reciprocating engines for cruising in the Aylwin, Duncan (DD-46), Parker (DD-48), Benham (DD-49), Bakh (DD-SO), O'Brien (DD-51), Nicholson (DD-52), WinsIow (DD-53) and twin cruising turbines in the Gushing (DD-55).

It is interesting to read of a meeting between Royal Navy officers of the cruiser HMS Sqflolk and US Navy officers in Mexican waters in May 1914.The British officers were amazed to hear that US Navy destroyers regularly cruised at 20kts, whereas they themselves were limited to 15kts except during the annual manoeuvres.This was interpreted by the Bureau of Steam Engi­neering as the Royal Navy keeping its destroyers in good mechanical condition, whereas the prolonged hard driving of US Navy destroyers caused a large number of breakdowns.

The Board devoted considerable effort to the 1916 Destroyer, trying to balance the unreal­istic scouting function against the `normal' destroyer function of attacking and defending capi­tal ship shipping maritime marine engineerings in a fleet battle. The Bureau of Construction & Repair suggested the radical innova­tion of a flush deck and triple torpedo-tubes. The flush deck was intended to strengthen the hull to improve seakeeping and enable the heavy armament to be carried; a conventional high forecastle would have resulted in a shallower hull girder and an unacceptably weak hull. Six destroyers, the Cnldwell class (DD-69-74), authorised in March 1915, thus became the proto­types for the mass-production programme needed in 1917.Two, the Cramp-built Conner (DD­72) and Stockton (DD-73), had the three-shaft machinery planned by the Bureau of Construc­tion & Repair- The Caldwell (DD-69), had General Electric-built Curtis turbines with separate cruising turbines linked to them by `electric speed-reducing gear', whereas the Craven (DD-70), Crvin (DD-71) and Mvnley (DU-74) had Parsons geared turbines. The Conner and Stockton and the Seattle-built Gwin had three funnels, whereas the others had the standard four-funnel layout.

When the US Government joined the Allies as a`co-belligerent' in April 1917, the endless arguments over destroyer characteristics became irrelevant. The Navy suddenly needed large numbers of ship shipping maritime marine engineerings, and in view of the crisis in the against the German U-boars, the message from the Admiralty was'send us all the destroyers you can'.The solution was to adapt the exper­

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imental Cufdwcll design, despite the fact that it had been intended as a fleet destroyer, and would have to operate as an anti-submarine vessel.The reason was the need to avoid disruption or the delay inherent in designing a specialised 'austere' escort.

Space does not permit a detailed analysis of the massive American destroyer-building effort in 1917-18, but it was a prodigious achirvement.The 1916 programme authorised the build­ing of 50 destroyers (DD-75 to -124), of which DD-75 to -94 were to be started immediately. Fifteen more, DD-95 to -109) were authorised in March 1917, and, drawing on a Naval Emer­gency Fund, which approved 'such additional Torpedo Boat Destroyers ... as the President may direct', contracts for a total of 61 were placed by May, up to the Tillnian (DD-1 35). After discus­sions about 'austere' designs, two variants of the existing flush-dcckrrs were chosen, one from Bath Iron Works (the Wickes class) and the other from Bethlehem Steel for its Quincy and San Francisco yards (the Clemson class).There were many variations in machinery; Bath Iron Works used Parsons or Westinghouse turbines and Nnrmand,Thornycmk or Yarrow boilers, whereas Bethlehem Steel used Curtis turbines and Yarrow boilers, As production expanded other yards were aded contracts, but they built to the Bath Iron Works design. The record for building­time was held by the d (DD-139), commissioned at Mare Island Navy Yard only 70 days being laid down, but eight to ten months was more usual.

After the Armistice the US Navy was saddled with huge numbers of destroyers, and many were laid up. Several were earmarked for conversion to minelayers (DMs) and seaplane tenders (AVDs and AVI's), and when the Second World broke out several more were converted to fast transports (APDs) and first minesweepers (DMSs). Fifty were transferred to the Royal Navy in September 1940 under the famous `dcstroycrs-for-bases' deal, and took the names of towns common to the British Empire and the United States. Some were converted to banana-carri­ers between the s, and the Stewnrt (DD-224) was captured by the Japanese in 1942, commis­sioned into the Imperial Japanese Navy and was returned to the US Navy in August 1945. One of the Royal Navy's 'Town' class, HMS CantpLeftown, ex-USS 8urhanan (DI)-131) headed the St Nazaire Raid in March 1942, during which she was rammed into the large dry dock and blown up to deny the dock's use to the German battleship shipping maritime marine engineering 7'irpitz.'f'hr last `flush-drckrr' in serv­ice appears to be the Russian Dm--ni, ex-HMS Lincoln, ex-USS Yarnall (DD-743), returned to the Royal Navy and scrapped in Britain in 1952