[TorpX]

Originally Posted by LCQ_SH

I just have one question? How to do a good estimation of speed?

.....

Plotting? Well, how are you supposed to estimate speed by plotting without updated contacts on the map?

Plotting is the best way. That is what RL USN skippers did.

It is not easy, or effortless, but will get the job done, if applied with skill. I think people become discouraged, because they start with the mindset that they should be able to come up with a tight firing solution, after plotting only 2 or 3 points.

There are only two differences between using map contacts and plotting yourself:

1. you must do more work; that is actually plot the points yourself.

2. you must deal with a realistic level of error (observational error).

The second point is probably the sticking point for most players. Realistic errors require that more points be plotted to sort things out
, and many dislike this. It also means that there are no 'sure things'. There is a real possibility of missing the target. Again, this is a realistic part of the game. Many attacks did fail for these and other reasons.

Once you have a good number of points plotted, it is a simple matter to calculate speed. I like to calculate speed based on a rolling average of the last 3 or 4 points. Relying on the last 2 only, introduces more error, imo. I usually don't include any from a great distance, as stadimeter errors make these dubious.

You can use the 'timing by wire' method also, but you must either steer the boat so the target is crossing your bow (or stern), or use trig to compensate for the angles. I find plotting easier, and must plot anyway, in order to develop the approach properly. Also, as you point out, you must know the target length. BTW, it wasn't the Navy that forgot to include the lengths, it was Ubisoft.