Editing Second Happy Time (section)

===U-boats in the Caribbean and the Gulf of Mexico===

{{See also|Operation Neuland|Battle of the St. Lawrence}}
[[File:Pennsylvania Sun.jpg|thumb|The tanker ''[[SS Pennsylvania Sun|Pennsylvania Sun]]'' torpedoed by {{GS|U-571||2}} on 15 July 1942 (was saved and returned to service in 1943).]]
The second wave of Type IX boats had arrived in North American waters, and the third wave ([[Operation Neuland]]) had reached its patrol area off the oil ports of the [[Caribbean]]. With such easy pickings and all Type IX boats already committed, Dönitz began sending shorter-range Type VIIs to the US East Coast as well. This required extraordinary measures: cramming every conceivable space with provisions, some even filling the fresh water tanks with diesel oil, and crossing the Atlantic at very low speed on a single engine to conserve fuel.

In the United States there was still no concerted response to the attacks. Responsibility rested with Admiral King, but he was preoccupied with the Japanese onslaught in the [[Pacific War|Pacific]]. Admiral Andrews' North Atlantic Coastal Frontier was expanded to take in [[South Carolina]] and renamed the [[Eastern Sea Frontier]] (ESF), but most of the ships and aircraft needed remained under the command of Admiral [[Royal E. Ingersoll]], Commander-in-Chief, [[United States Fleet Forces Command|Atlantic Fleet]], who was often at sea and unavailable to make decisions. Rodger Winn's detailed weekly U-boat situation reports from the Submarine Tracking Room in London were available but ignored.{{citation needed|date=January 2022}} By April, Allied forces along the US east coast included 80 small patrol ships in the USN [[Eastern Sea Frontier]], 160 US aircraft, 24 RN ASW trawlers, and one British [[RAF Coastal Command|Coastal Command]] squadron. By British and Canadian standards these were enough to begin convoying, but no comprehensive convoy system was implemented that month.<ref name="milner_2011_ch4_april_convoys"/> Instead, on 1 April the US implemented a partial convoy system where convoys moved along the coast in short hops, moving during daytime and stopping in protected anchorages during nights; these were slow and ineffective.<ref name="churchill_1950_122-123">Churchill (1950): pp. 122–123</ref><ref name="milner_2011_ch4_april_convoys"/>

Coastal forces were reinforced from the [[Mid-Ocean Escort Force]] (MOEF) before March. The US contribution to the MOEF fell to part of one   group. Five RCN corvettes were withdrawn to escort the new [[BX convoys|Boston-Halifax convoys]], the first convoys along the American seaboard.<ref name="milner_2011_ch4_moef">Milner (2011): chapter 4 ("Mid-ocean escort forces were further squeezed...")</ref> In April, a [[Royal Navy]] (RN) group redeployed to the Caribbean to defend tankers.<ref name="milner_2011_ch4_april_convoys">Milner (2011): chapter 4 ("In the spring of 1942, the possibility of future problems...")</ref> The RCN attempted to reinforce the MOEF by using training ships in supporting roles.<ref name="milner_2011_ch4_moef"/>

Allied tanker losses were alarming. Losses along the North American coast and in the Caribbean accounted for most of the 73 American tankers lost in the first half of 1942, and 22 British tankers lost in March; three out of the four largest Canadian tankers were also lost from February to May. In March, British Prime Minister [[Winston Churchill]] urged the USN to organize coastal convoys, to little effect. The next month, British tankers from the Caribbean avoided the US coast and sailed east to [[Freetown]] in [[Africa]],<ref name="fisher_oil_34"/> while between 16 and 29 April the US ordered US and Caribbean coastal waters closed to commercial tanker movement.<ref name="fisher_oil_35"/> On 26 April, the US agreed to allow Britain to redeploy a MOEF group to establish Caribbean convoys, but the US refused to start its own Caribbean convoys or to provide escorts.<ref name="fisher_oil_36">Fisher (1993): p. 36</ref>

Eastern Canada was dependent on imported oil from the Gulf of Mexico and the Caribbean.<ref name="fisher_oil_33">Fisher (1993): p. 33</ref> The crisis led to gasoline rationing on 1 April, and the potential consequences of the US-ordered halt to tanker movements were severe. On 28 April, the RCN started [[ad hoc]] convoys to bring Canadian and Canadian-charted tankers trapped in the US and the Caribbean back to Halifax. On 1 May, the Government of Canada insisted that Canadian tankers be escorted, leading the RCN to organize formal convoys to the Caribbean through US coastal waters.<ref name="fisher_oil_35"/> The RCN had only enough escorts to run convoys from Halifax to Trinidad (coded as TH); the loss of supply from other regional suppliers had to be accepted.<ref name="fisher_oil_36"/> In July, Trinidad was replaced by Aruba to accommodate British tanker movement. From May to August, fourteen convoys – including 76 tankers and 4 million barrels of oil – were run without a single ship lost. The convoys were discontinued in August with the advent of the US's comprehensive convoying system.<ref name="fisher_oil_37">Fisher (1993): p. 37</ref> Canada also began convoys between Nova Scotia and [[Quebec City]] in May.<ref name="milner_2011_ch4_overextension"/>

The search for Allied tankers and the support of {{GS|U-459||2}}, a Type XIV, pushed the U-boat offensive into the Gulf of Mexico.<ref name="fisher_oil_36"/> On 21 April, ''U-459'' was 600 miles north-west of Bermuda; it refuelled fourteen U-boats through 6 May, including Type VIIs, headed for the Gulf and the Caribbean. In May, they sank 115 ships (of which 101 were steaming independently), about half being in the Gulf, with half of that tonnage being tankers. In June, they sank 122 ships, of which 108 were sailing independently. The Gulf Sea Frontier, formed in early February, had barely any resources and was ineffective.<ref name="milner_2011_ch4_gulf">Milner (2011): chapter 4 ("As U-boat attacks spilled into the Gulf of Mexico...")</ref>