Drifting on the open sea off Scilly

We went out on a boat 10 miles off Scilly to look for Wilson's Storm Petrel. The engines were turned off for 2 hours and we just drifted. It took me a long time to realise that looking straight out for the back of the boat was not showing me where we have been. It seems that we were moving sideways with the swell. You might be able to spot the movement of the waves in the pictures above. I hadn't really thought much about drifting. Turns out it depends a lot on the design of a particular boat but is due to both wind and current. see http://www.ybw.com/forums/archive/index.php/t-91754.html I think that the swell is likely to give some information about the wind direction rather than the current, but the swell could have been set up by winds on the other side of the ocean some days ago.