Mockery greeted the poor chap who thought he was sailing along the south coast but had, in fact, been circumnavigating the Isle of Sheppey for 36 hours. An easy mistake, surely: the coast there looks much the same, give or take some white cliffs.
Besides, there are precedents. Columbus had no idea where he was, and Africa was once full of people like Livingstone stumbling across waterfalls and such. Douglas "Wrong Way" Corrigan took off in a small plane from New York for California in 1938, and ended up in Dublin. I note, too, coastguards advised the sailor his best way to Southampton was by train. I'm not sure: recently, two Chinese students asked a guard at King's Cross the way to Tate Modern and ended up in Todmorden.