By early 1942 total U-Boat strength is up to 250 boats with 90 operational at any time. The United States has entered the war on the Allies' side, but its naval forces have little experience fighting U-Boats and Admiral King does not believe that the convoy system is necessary. Chief U-boat commander Admiral Doenitz launches Operation' Paukenschlag' ('Drumroll'). Its aim is to attack as many ships as possible along the American east coast before the Americans can adopt anti-U-Boat measures. The U-boat commanders called this their 'Happy Time'. There are hundreds of unescorted merchant ships sailing in virtually peace-time conditions off the American coast. They make quick and easy targets for veteran U-Boat commanders. Warship patrols are started, but the US Navy leadership refuse to accept the hard-fought lessons of the Royal Navy and establish convoys immediately. Atlantic convoys still start and end at Nova Scotia, so the first U-boats operate off the Canadian coast south of there. Over 40 merchantmen are lost in this area alone in January and February. By this time U-boats are also sinking many ships off the US east coast.