I'm not so sure about the Watch Officers methods though, I'd rather use the Stadimeter or Sonar ping to find range. Maybe I'd use him for finding the final range before firing as this has less impact on the gyro, but deffinately not for plotting a target's course and speed. The difference of 50m to 100m can make a difference for plotting but not so much for a final range estimate. Just my opinion.

I go with the exact opposite approach and don't use the stadiometer at all, nor do I use the notepad at all other than to add in ship id (as a reminder to myself when I later do a last minute check on torpedo settings before firing). I compensate for the WO's "accurate to only within 100 meters) by taking several plots over time as I close, parallel & overtake (or outrun/outflank) and finally intercept at 90 degree AoB. All of that takes time and the dozen (minimum) range and bearing plots from the Watch Officer's observations will give what I consider an accurate enough line of best fit for the target's course and speed, which I can then derive range from using the protractor & ruler (to within 100 meters which is accurate enough for range).

I edited out my starshells and AP long ago, as U-boats didn't carry either one.

How do yu edit out the AP & star shells ?

Most U-Boats had their Deck Guns removed by 1943. Opps another flaw in the game never mind.

Go to the Data/Cfg folder. Click on Basic.cfg. Way down near the bottom of the file, just below 'Coning', which is all the conning tower files, you'll come across the gun files: '10.5cm', '8.8cm' etc. Those two files have the ammo loads for the deck guns. You can change them to anything you want; thousands of shells if you like.

The historical loads should read:
10.5cm: AP=0, SS=0, HE=150
8.8cm: AP=0, SS=0, HE=220

Thank You very much, from my deck gun crew, they were getting teased by the other U-boats for loading starshells.. :88)