RAF Sandy Bay
Another exciting activity on Lough Neagh during world war two was the formation of a flying-boat base in Sandy Bay in the shelter of Rams Island. The entire bay was surveyed before laying down twelve flying-boat moorings with special rubber buoys and pick-up harness, also a number of marine craft moorings for attendant vessels and refuellers, plus four flying-boat moorings east of Rams Island (sheltered from westerlies). In order to guide the flying-boats and marine craft out into the open Lough, a number of navigation buoys (gas-lit, flashing) were laid out, tracking to the north of Rams Island and also to the south. Sunderland flying boats used these moorings and service facilities for the remainder of the war.

Sandy Bay Airfield was built as a seaplane base with moorings for flying boats. It was situated on the eastern shores of Lough Neagh, close to Ram’s Island.The US Navy decided in 1942 not to use Killadeas as a base for Catalina flying boats however US Navy aviation saw plenty of action throughout the war. In October 1942 US Navy amphibious Catalinas appeared at Ballykelly en route to Morocco and continuted their anti-U-boat patrols, sinking two and damaging several more.Lough Neagh became the main base for the US Naval Air Service in Northern Ireland during the Second World War, with Sandy Bay and Ram’s Island becoming key locations. They were the UK terminal for a scheduled twelve times weekly service operated by the US Naval Air Transport Service Consolidated Coronado flying boats from and to the La Guardia terminal in New York. These services conveyed personnel and urgently needed supplies, under the control of the US Navy Commodore at Londonderry. However the RAF was responsible for the provision of accommodation and messing for these transit crews and their control staff. They were accommodated in buildings that were erected at the residence known as Ben Neagh close to Crumlin and Sandy Bay. Many of the Coronado pilots were civilians seconded under contract by Pan American or American Export Airlines.This service was part of the build up to D-Day and was inagurated on 18 May 1944, when a Coronado arrived from New York. This was the first of 538 crossings of the Atlantic made by these large flying boats during that summer, the normal load being 9 crew, between 10 and 18 passengers and freight. Up to 11 movements a day were recordered in the lead up to D-Day. Despite the frequency of these movements, there was only one accident recordered. On 17 July a Coronado was holed on some rocks at Sandy Bay. It was repaired at returned to service.These planes were not fast and transatlantic journies took well over half a day, at a cruising speed of 150 mph.On 15 October 1944 all services were terminated.Information above from Ernie Cromie and his book Overhead and Over Here.

From May 17/18, 1944, in the run-up to "D-Day" on June 6, a fleet of four-engined Consolidated PB2Y Coronado flying-boats added urgent passenger and cargo capacity across the North Atlantic to Britain. The U.S. Navy PB2Y-3R boats were flown by Pan American crews, American Overseas Airline crews and RAF crews from 231 Squadron. One aircraft 7230 set a record flight time of 14 hours and 18 minutes from Sandy Bay to Shediac New Brunswick in July 1944.
It is recorded that 31 U.S. Navy PB2Y Coronados were contracted to the Atlantic Division of Pan American Airways and American Export. Engineers had to make 96 modifications to the fleet of flying boats for their new transport roles, including removing guns and bomb racks, faired-over turrets and passenger and cargo accommodation. Stripped of offensive and defensive armaments, transport configurations were designated PB2Y-5R. After conversion, the standard transport PB2Y-5R was configured to operate as a cargo or personnel transport, hospital vessel, or flagship. Cargo of 7260kgs could be carried. 44 passengers could be carried or 25 stretchers. The aircraft were unarmed and flown by Pan American Airways and American Export Airways crews carrying passengers and freight.
The first transatlantic service by PB2Y Coronado was operated by the U.S. Navy Naval Air Transport Service from New York to Sandy Bay, Lough Neagh, via the flying-boat base at Botwood Harbour in Newfoundland. Here, a meteorological officer, Hugh Lacey, kept a diary of many of the arrivals and departures through the base. His log reveals that at 1610 hours on May 17, 1944, a PB2Y Bu No. 7219, flown by Captain Durst, alighted from New York. It departed later that day for Sandy Bay. . . . . 

From May 1944 Sandy Bay  also served as an airport for flights between the U.K. and the U.S.A.
The main users were the U.S. Naval Transport Service and RAF Transport Command, both operating PB2Y Coronados. 
Sometimes the aircraft flew from Sandy Bay via Port ​Lyautey in North Africa and RAF Darrell's Island in Bermuda to the United States or Puerto Rico.
The service was well used with a recorded 280 passengers in June 1944 alone.
Still, the service ceased on 16 October 1944. 

PB2Y Coronados hauled ashore being serviced at RAF Darrell's Island during World War II.

Acknowledgements  and thanks to the Late Jim McGarry and Wikipedia

Consolidated PB2Y Coronado
The PB2Y Coronado was a large flying boat patrol bomber designed by Consolidated Aircraft. After deliveries of the PBY Catalina, also a Consolidated aircraft, began in 1935, the United States Navy began planning for the next generation of patrol bombers. Orders for two prototypes, the XPB2Y-1 and the Sikorsky XPBS-1, were placed in 1936; the prototype Coronado first flew in December of 1937.

After trials with the XPB2Y-1 prototype revealed some stability issues, the design was finalized as the PB2Y-2, with a large cantilever wing, twin tail, and four Pratt & Whitney R-1830 radial engines. The two inner engines were fitted with four-bladed reversible pitch propellers; the outer engines had standard three-bladed feathering props. Like the PBY Catalina before it, the PB2Y's wingtip floats retracted to reduce drag and increase range.

Development continued throughout the war. The PB2Y-3, featuring self-sealing fuel tanks and additional armor, entered service just after the attack on Pearl Harbor and formed most of the early-war Coronado fleet. The prototype XPB2Y-4 was powered by four Wright R-2600 radials and offered improved performance, but the increases were not enough to justify a full fleet update. However, most PB2Y-3 models were converted to the PB2Y-5 standard, with the R-1830 engines replaced with single-stage R-1830-92 models. As most existing P2BY-3s were used as transports, flying low to avoid combat, removing the excess weight of unneeded superchargers allowed an increased payload without harming low-altitude performance.

Coronados served in combat in the Pacific, in both bombing and anti-submarine roles. Transport and hospital aircraft were the most common, however; the aircraft used by the British under Lend-Lease were outfitted purely as transports.

Operators
Royal Air Force.
United States Navy.

7223 On 17 July 1944 BuNo 7223, being operated on a scheduled flight by American Export
Airlines, Inc., Captain H. M. Geselbracht, Jr., in command, was involved in a taxiing
accident at Lough Neagh, Ireland, resulting in major damage to the aircraft. Following
instructions from the Navy, on 4 October 1944, BuNo 7223 was returned to NAS Patuxent. 
Crew: Pilot Captain H. M. Geselbracht, Jr.; Frederick H. Anderson; 
Floyd P.Stout; George M. Cole; Claud L. Gardner; Dudley J. Bennett; Gail M. Engle; Robert H.Brandt; and Stephen T. Prezalary. Captain Geselbracht had flown previously with the Flying Tigers in China.

On 28 January 1943 No. 330 Squadron moved to Oban from Reykjavik, Iceland and during the following month converted from the Catalina MkIII to Sunderland Aircraft. The Squadron, together with its sister Squadron, no. 333, was formed of Norwegian personnel.  At the fall of Norway several Northrop N-3PB floatplanes previously equipping units of the Norwegian Naval Air Arm were flown by their pilots to British bases. These aircraft, although obsolescent, had been the first equipment type for the newly formed 330 Squadron until the provision of Catalina’s was possible. Two of the redundant N-3PB aircraft were dismantled and stored at Oban. The work up and conversion to Sunderland aircraft was speedily achieved and the first operational sortie was made on the 20th April 1943. The first loss on the new aircraft type occurred on 12th May 1943 when Sunderland W6075 crashed on landing and sank at Rams Island Lough Neagh, Northern Ireland. 330 Squadron leader Kpt. Ltn. Christian Roy Kaldager and his  Norwegian crew were safe.  Sunderland W6075 was recovered by H. McGarry & Sons and towed into RAF Sandy Bay. It was then dismantled and taken by road to the Shorts factory in Belfast but was later wrote off as too badly damaged for economical repair. It is worth noting Kpt. Ltn. Christian Roy Kaldager  went on to become a Royal Norwegian Air Force Major General.