Having read recently that using high time compression means that you are missing out on some air and ship contacts I've gone to playing at no greater than x256. Which makes for a long tedious crawl on the map. To help pass the time I've started using the marker tool to mark the sub's postion every 12 hours at noon and midnight. Then I use the ruler tool to draw a line between each mark. When the patrol is over I save the last map image to the clipboard, open it up in a graphics program and draw over the line and mark where I sank each ship. Then save it. At the very least it gives you a graphic record of what you did on each patrol. I've found that by the time you reach 1942 you're having hard time remembering where you went and what you did on those first duck patrols in 1939. However, on those patrols where you do a lot of concentrated zig-zaggy search patterns you'll probably have to fudge a little.