[abaileyatd]

After a brief period of observation you should be able to determine if the target is approaching or moving away from you, and also generally which direction it is heading. I approach first by assuming a generally parallel course, keeping myself at the edge of whatever visual distance I'm comfortable with. Adjust overtime to keep your target(s) at the edge of your view. U-boat commanders handbook recommends keeping only the top of the masts in view when overhauling during the day, perhaps a bit closer at night. SH3 GWX was very forgiving in this aspect IMO- SH5 TWOS is not. Seriously- during the daytime keep the masts barely showing if you want to be 100% safe. This is early war also, with radar adjust accordingly.

Once I "feel" I'm far enough ahead, I turn in- generally gradually, towards a 90 degree intercept (approximate at first, adjusted as necessary as the target(s) approach, although overhauling generally gives me a pretty good idea of course and even a relative speed estimation). When the nearest ship gets close enough to make me uncomfortable, I go to periscope depth, rig for silent running and hope I can make the distance. Ideally you arrive within 2000m at a 90 degree AOB. As they approach closely, you can use the RAOBF to determine accurate ranges, AOB and if necessary speed. Adjust TDC from your initial estimates to these values and go to town. This is for convoys. Single targets the idea is similar but you may be more brash as circumstances apply.

When at periscope depth, keep your speed down, stay silent and again as per Uboat commander's handbook practice judicious use of periscope (which is kept partially awash when exposed), especially within 4000 meters. TWOS is again very uncompromising about this and I find that my periscope usage must be the most conservative it has ever been in this game and modpack. Following the aforementioned rules works pretty well, but don't be surprised to be spotted on the final attack, just hope you are close and your TDC values are accurate.

As always, immediately after the attack begin appropriate evasion tactics.

Note: this is a conservative tactic, but one that is successful for me. Uboat attacks are more art than science and as always you must be ready to adapt and act more aggressively when the opportunity presents itself.

I also forgot to mention that IDing your target is essential for RAOBF usage, and for me is truly the most challenging aspect. Begin IDing as early as possible, even over the horizon you can get a general idea of ship class, and with mast layouts and funnel counts begin to narrow it down considerably. Continue to verify your ID until the final attack. If you cannot get a solid ID, you must at least determine class of ship, hopefully narrow it to a handful at least, and look at lengths and mast heights and just try to average it or best guess. I've had success even with flimsy IDs by cutting the difference, getting close and praying!