[Corsair]

You really should try manual nav one day, patrols are never boring and planning your attacks with no position on the map forces you to use methods close to how it was in real... It took me a long time to get at it, but I wouldn't go back to GPS nav anymore...
Some of my best times have been finding a port entry at night in heavy fog and bad weather...
I admit I have been doing a lot of navigation on sailing boats IRL and I love it... in fact if you do the plotting properly on the map and keep a close look on the compass to correct the heading when it drifts (of course using low TC - I use max 128 and sometimes 64 in bad weather), you are never very far away from your supposed position, even after several days of estimated navigation. A useful feature is also changes in depth when you come close to shore to confirm your position.