[Zantham]

There is no way to actually enter the speed at the periscope view, you have to do it from the attack map on the U-Boat.

You can attempt to get a contact's speed from the periscope using the notepad. This involves doing a few range sightings with the stadimeter and sending that information into the TDC, and after you send it a few times your weapons guy will have enough info to estimate speed for you, which on the notepad screen you hit the Chronograph symbol.

If he has enough information he'll tell you a speed (not always accurate I've found) or tell you 'not enough information' uin which case wait another 30 secs or so (longer is better), do another stadimeter reading, then go back to the speed part of the notepad and try to get the weapon officer to estimate it again. His estimate will also largely depend how accurate you were in sending precise ranges.

I've probably just confused everyone more with this post lol