We looked at the tidal charts, analysed the currents and decided that leaving Possession Island at 4am would give us a helping current to the end of Endeavour Strait, then the tide should turn and give us a help away from the Torres Strait Islands, then there is supposed to be a helping current across the gulf of up to one knot. Great, and all downwind as well, we estimated 45-48 hours with the forecast of 15-20knots. WRONG!! We had a half knot current out of the Endeavour Strait, then a knot of contrary current for most of the crossing, that occasionally reduced and gave us about a 1/3 knot helping current for about an hour, but mostly the current was against us, turning 350 miles over the ground to 390 miles on the clock. With lighter winds than forecast (until we had 25-30 knots after dark the first night) and a 1.5-2m sea and swell (from 3 different directions depending on the tide status) the trip actually took us 52 hours.