sitting on the bottom

[Sailor Steve]

Originally Posted by Phil

is sitting on the bottom an effective technique of evasion or is it to loud when you hit the bottom? saw it the other day in the movie enemy below

Originally Posted by johnno74

Active sonar "pings" are actually reflected by density changes - they don't bounce back towards the sender from your hull, they bounce back from the air space inside the pressure hull

So, in reality, sitting on the bottom shouldn't help you evade active sonar.

Originally Posted by GT182

It's better to move off and away at 1kt to try to evade. Sitting on the bottom just makes you an easy target.

In reality sitting on the bottom had one great effect: depth charges would either go off too shallow, or they would hit the bottom and sit there. Even if they went off on the bottom the blast would be directed upward, rendering the submarine reasonably safe. Several captains reported surviving 12-18 hours of depth-charging by sitting on the bottom. It was an accepted doctrine that a rough seafloor could indeed deflect sonar beams in odd directions, also decreasing the likelihood of detection.

Unfortunately, none of this is modelled in the game.

[Keelbuster]

Originally Posted by Iron Budokan

What about running shallow? At the beginning of the war the sub commanders used to run at periscope depth to evade DDs because they knew their listening gear couldn't operate at that angle. Is that modeled?

This can be quite effective. In medium sea states, you can achieve some stealth by riding at PD. I always begin my evasion at PD, and I only dive if i have to. Visual information is so rich that I always prefer to keep it. When you see them go into their attack run, you can go flank and break right or left, and they often won't hit you with their DCs. You can see which way they turn, and plot a flank evasion course. If necessary, you can take a shot at them (zero gyro, mag pistol). And, if I have to dive, i don't like to go below 40m: i like to be able to see my attacker's course on the surface through the observation scope. THis makes my DC evasion easier. The only time I would go really deep is if a) there's no bottom and b) there are many attackers and no other way out. With 1 or 2 attackers, PD is a good place to be. The other thing is that diving saps speed - by going down to 150m, you waste velocity that could have been spent gaining lateral separation from your attackers. Finally, I like to 'spend' depth during evasion. For instance, in the first DC run, maybe the attacker knows you are at PD, so he sets his charges for min depth. In the evasino run, you drop to 30m and he misses. In his second run, he knows you're at 30, so you drop to 60. In the third you drop to 90, etc. If you drop all the way to 150 in the first attack, you've got nowhere to go but up! Also, if you get hit at that depth, you might just pop. So - my feeling is that you should use depth sparingly. Maybe I'm drifting OT now?

Kb

[danurve]

Originally Posted by GT182

It's better to move off and away at 1kt to try to evade. Sitting on the bottom just makes you an easy target.

I'm thinking sitting on the bottom in an IX makes you a bigger target.