I've divided the Arctic explorers into three groups, first the very early explorers who sailed between 1576 and 1616, second a group who approached overland from the south in later years, and finally those who came in search of the frozen Franklin after 1845.
Martin Frobisher sailed in search of the Northwest Passage three times, between 1576 and '78, never getting further than the southern end of Baffin Island where Frobisher Bay is named after him. During his first voyage he got distracted by thinking he had found coal. At one point his fleet was blown into what is now Hudson Strait, but Frobisher named it Mistaken Strait, thinking it would not provide a route west. Instead he believed the narrow Frobisher Bay (which went nowhere) would be the route.
His third voyage was a fleet of 15 ships no less, in search of the 'coal'. Gathering a good supply he sailed home with his valuable cargo, only finding out on his return to London that it was worthless rock.