sonar readings are inconsistent

[I'm goin' down]

My sonar man reads differnet ranges each time I ask him for range and bearing information. Is he stupid? Is sonar inaccurate by nature? What is the story and solution, if any.

[CapnScurvy]

I know I've answered this before; when asked to give a sonar report of a target, the sonarman will only give you an "estimate" of range. Depending on his skill level will determine the "estimates" accuracy (which is never accurate, some just happen to be more accurate than others).

If you want an accurate sonar finding, you have to take the sonar reading yourself. Once the target is "pinged"; a return ping is heard; the reading is "Sent" to the TDC. The accurate range to target is displayed in the Range readout of the Position Keeper.

[I'm goin' down]

I do not think so. In my experience, when I ping the target several times, the reading are off by hundreds of yards, sometime by over one thousand yards. Someone else advised me to ping the target and wait for the return ping, but the results were as I already noted. I'll keep trying.

I cannot finish the mission in late '41 to drop the agent in the Bungo Strait. Tokkyo's Revenge with map contacts disabled. The dd and its companion, a small split freighter, lurk nearby and find my boat every time. You know what that means....!

[magic452]

IGD If you want a good sonar ping you must be sure the sonar is pointed at the center of the ship. Move the sonar left and right and get the center of when the light goes on. That's about as accurate as you're going to get in this game. It's pretty close if you do it right not so good if you don't, just like real.

Magic

[I'm goin' down]

Majic, I try it. I have not been able to get an accurate course using sonar readings. With map contacts disabled, lack of an accurate target course makes the attacks much more difficult.

[Rockin Robbins]

Originally Posted by magic452

IGD If you want a good sonar ping you must be sure the sonar is pointed at the center of the ship. Move the sonar left and right and get the center of when the light goes on. That's about as accurate as you're going to get in this game. It's pretty close if you do it right not so good if you don't, just like real.

Magic

And interestingly, this center slop on the sonar bearing is less than the real sonar, which was even more uncertain in direction. Actually the width of the sound was dependent on sea conditions, something not modeled in SH4. We can be pretty sure (okay, POSITIVE) that the width of that audible sound is 10º. In real life it could be variable from day to day and position to position.

So we can carefully note the bearing where we begin to hear the sound on both sides, and surprisingly (irony...) note that the signal is 10º wide. Just add or subtract 5º from either of the extremes and you have your bearing.

Of course, our sonar man, regardless of ability always can tell the exact bearing of the target. Just set your sonar on that bearing and ping.

Actually, in real life, knowing the bearing of the target isn't all that you need to know to ping him, because you want the signal to hit the MOT (middle of target) when it gets there. So you have to anticipate where the target will be then, after the ping travels at 1100' per second (more or less depending on water density and temperature!). This is not modeled in the game.

Even using the sonar man's bearing, successive pings will come back with a variance in distance. It's best to take four or so and average them, as shown in WernerSobe's sonar targeting video. The active sonar ranging may give you a variance in range but it is plenty good enough to put the enemy on the bottom, either with WernerSobe's technique or the Dick O'Kane Sonar Only technique.

My feeling is that our sonar is too accurate compared to the real thing.

At the same time it lacks subtlety. No attempt was made to have different ships make different sounds, aside from merchant vs warship. The motor sounds do not change with throttle setting, there are only three sounds, slow, medium and fast for each type. Therefore screw counts are impossible, which is good because screw counts couldn't be used in WWII to deduce target speed. There is no variance in sonar conditions with temperature and density of water, and there is no background noise from the life in the water. We do not have the filters the real sonar men had to separate the sounds we are interested in from the sounds we are not. We can't vary the volume either. The only control we have is when to ping and in what direction. When we ping, we can get the range before the return ping is received! This is a very small subset of the function and environment of the real sonar systems.

[Diopos]

You're so obsessed with "range". I'd trade a good target course and speed estimate with laser precision range anytime. WHAT?!?. Actually I'm trying to improve my "Bearings-Only" techniques. They come really handy in the pre-radar phase of the war and in the "final approach" where you'd probably wouldn't be able to use the radar to confirm and refine the target's data. Eventually, if you're close enough, 0-gyro angle torp shots remove the necessity for extreme range accuracy (bit still you need a good course and even more a speed estimate). Active pinging is not included in my gaming style at the moment but I'll be sticking to "Contacts Off" permanently.
My (limited) experience with active sonar is that if the overall range to the target is "small" the readings are not bad. My feeling is that the game may have problems handling relative motion, Try multiple pings with the sub stationary and see what happens. Even better, try a "mission" where both target and sub are stationary at a known distance and see what's the active pinging result. Maybe even "calibrate" the thing at varius predetermined ranges and see what happens.That would be really useful to all of us.

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