Well, hey there! Thanks for dropping by. Pull up a chair and feel free to pull yourself one of those semi-adult beverages over there whilst I dig up a couple answers here:
Well, if all you want to do is take a couple of range/bearing observations and not plot them on the chart (why would you want not to use a plot?) there is a way to find the course and speed using only the TDC. Our game developers crumbled to repeated requests and included a calculate speed and course button on our TDC. I think that's a tragedy, but here's how it works.
You take two different stadimeter readings of range/bearing at least 10 seconds apart. Then you proceed to the speed input mode of the TDC input dial and press this button:
Now your accuracy is strictly dependent on the accuracy of your two observations and is rendered more accurate by increased time between observations. Keep in mind that stadimeter and accuracy are two words that probably shouldn't be allowed to occupy the same sentence.
With radar, using the plot and actually measuring the distance between two positions three minutes apart, drawing the course and measuring it is a technique that will give you MUCH more reliable information on all parameters, speed, course and range.
The fastest method of determining true course is to spend an unreasonable amount of time playing with gutted's
Solution Solver, quizzing yourself with his AoB sight determination gillhickey on there. With MUCH practice you can do like the real sub skippers used to do: sidle up to the periscope, take a gander and intone "Angle on the bow 47º starboard." As long as an accurate bearing is in the TDC, entering the AoB will cause the target's bow on the output dial of the TDC to point to that AoB. You'll notice an outside ring of numbers there also. They are the true course, which you can read outside the AoB number. WernerSobe's video on manual targeting explains and shows this process.
Well, that's the good news. The bad news is that picking out a single sonar contact in a crowd is pretty impossible. Contacts have to be several degrees apart to resolve them as individuals. Even when you can resolve them, how do you know you are picking up the same one for two different pings? Even with continuous monitoring (which would keep you from skippering your sub, most un-commander like) two contacts could cross and you could be following a different one for your second ping. The verdict: sonar only is not suitable for convoy situations.