Vixen
Penultimate Amazing
Current, wave and wind all contribute to the speed of a ship over the ground.
Why are you using degrees of latitude to work out the total distance sailed?
OK, let's try distances instead.
18 knots x 6.55 hours = 117 nautical miles = 135.67 miles or, 218 km. So, 208 km to go. Just 5 km out either way. (Half way point of 426km is 213km).
Distance wise it was at the half-way stage, give or take 5 km.
Assumptions: Tallinn to Stockholm is 426 km. Utö to Stockholm is 193 km. The wreck is 40 km from Utö, South-South-East. However, Utö has very similar coordinates to the wreck so no real adjustment required, but we could allow for 20km or so more needed., say 213km away.
It had been travelling since 19:15 so by 1:48 (six hours and 33 minutes) it was 6.55 hours into its journey when it went off the radar.
