I have got Silent Hunter: Wolves of the Pacific, and am struggling to be any good at being a submarine commander. Even at the easiest difficulty settings, I’m really letting my crew down, almost always getting sunk before I manage to sink anyone. And detected constantly.
I know virtually nothing about real sub tactics, fwiw.
The manual is pretty rubbish on strategy.
Anyone else play this and have tips?
Haven’t done that particular Silent Hunter, but I’ve done other of the SH series and plenty of other sub games besides. The basics are all the same anyway.
First, be always in mind that you are basically one step up from a rowboat when it comes to combat capability. WW2 subs especially are slow, fragile and poorly armed. Attacks will only ever succeed with the element of surprise, and survival comes entirely from stealth. Stealth is achieved by not being seen and not being heard. In short, the deeper you are, the slower you’re moving, and the less you’re doing, the safer you are.
The skeleton of an ideal attack is positioning yourself close in the path of a convoy, well ahead of them and preferably at night. Submerge to periscope depth and, as the convoy approaches, determine the juiciest target and its speed & heading as accurately as possible as quickly as possible. Lower periscope and dive deeper to move into a position that will have your target pass very close by, with their escorts at a distance or at least on the opposite side of the target. Reduce speed as the convoy closes to avoid detection. As they approach firing range, come back to periscope depth, take one last (and very brief!) look to confirm the targetting solution and escort positions, fire enough torpedoes all at once to cripple or sink outright your target(s) (plus more for dud safety) and as soon as they’re fired, dive as deep as is safe and creep away from the escorts at a very low speed. Do not try to run from them at full speed - they will hear you, and they are much faster than you. Once they’ve lost the scent and have wandered off to a safe distance, come back up to check out the damage and if you’ll need to hang around to finish off stragglers.
The details can change significantly based on the makeup of the convoy, the number and type of escorts, the date in the war which determines the technology available and the environment the encounter is taking place in. For instance, if there’s only one escort, maybe you want to grab the tiger by the ears and engage that first - free pickings of the convoy if you succeed.
If you’re entirely new to the sub genre you’ll definitely want to read the game’s documentation to get a background on sub warfare and learn how to interpret critical elements like the hydrophones and target data computer. Even if you delegate them to AI crew control, it’s important to know what bad data looks like and when they can be trusted.
Sub combat is all in the planning, doing as much as possible with the conflicting constraints of time and stealth. It’s slow paced, but can be riveting despite that once you appreciate what’s going on. If things ever wind up being busily exciting, it’s not likely to end well for you 
I have Silent Hunter III, and have found lots of help and tips here: SUBSIM Radio Room Forums - www.subsim.com Submarine games, reviews, forums, books, naval news
Adding a few mods really improved the game, in my opinion. Have fun.
Thank you, Mekhazzio and hermann my friends; have since managed 50k tonnes of ships sunk before blowing up. I certainly deserve to hit seven figures but perhaps will manage that soon 
If I ever get any good are either of you, or other lurkers, interested in a multiplayer game? I believe that to be possible…
You’re welcome. I’ve never tried multiplayer games, but you might have some luck at that site.
You could try another game or two as well. I haven’t really played any sub games since 688 Attack Sub and Gato, so that tells you how long it’s been. (My father likes them, but I could never get into the more realistic ones.) It’d be another way to learn tactics and strategy, even if it doesn’t correspond directly.
Yeah-get one of the SH IV megamods (either Real Fleet Boat or Trigger Maru, combined with the custom campaign Run Silent Run Deep), as they fix tons of bugs in the vanilla version (even if fully patched). All easily available at the Subsim link above. Some lunatics are currently working on a surface ship mod (yes, you’ll be able to blast things with the Yamato or Missouri). Ask away if you have any more questions (tho I personally haven’t subsimmed in several months).