Just to throw my $.02 worth in there, see what I use, attached.

Thanks for that, when I tried 5kts was more efficient than 6kts but Im not sure about how to order 5.75kts?

You dial in the exact speed you want on the knotmeter rather than the telegraph. If you would like a larger dial to make it easier, see here: http://www.subsim.com/radioroom/showthread.php?t=211313

Thanks I have installed and had a quick play, nice big dials, got to work so will try out properly later.

Never did get to DH55, reported convoy on english coast so attacked it before getting to english channel used all 5 torpedos for a medium cargo and a destroyer then back to wills.
On restarting commander has retired me after 10 missions, new career now in a VIIB.