Wind and currents troubles with 1.03

Dr.Sid · 02-12-06, 05:43 AM

Well .. there is no change in currents, they are still the same. Which means almost useless. Currents work like this: they add specific vector (of the current) to the ship speed. That's all.

It means for example that if there is 3kts current and the sub goes 10 knots in the same direction, it will loose periscope, because total sub speed will be 13 knots. In reality speed of the sub against the water is still 10 kts, so there should be no problem.

Currents also don't affect towed arrays, so it's quite easy to loose it with strong currents. On the other hand, strong currents are rare in the seas and so in the custom made scenarios, so you will loose nothing if you simply turn the currents off.

There seems to be bigger problem with winds in 1.03 (I did not noticed this with older versions). Wind works exactly like the currents except that it works on aircraft. Here it is not much problem, because there are not so tight speed limits, and the wind should not affect hydrophone while it is in the water (but currents shoudl !).

But the wind in 1.03 seems to affect surface ships too ! In exactly the same way ! It means if you have 5 kts wind, and you turn OHP agains the wind and order 5kts, you will stand dead in the watter. Problem is that many scenarios use at least weak wind which now affects heavily especially OHP performace. You can easily get into negative speed, and if you move slow, it's hard to get where you wanted to go.

Fast fix is of course to switch winds off too.

Three14 · 02-12-06, 07:28 AM

Been wondering this for awhile...

If you order all stop, will you drift? Or, put another way, is there a way to get the boat to drift with the current and another way to make sure it stays put?

Dr.Sid · 02-12-06, 08:40 AM

You always order speed agains water (air) .. not agains ground. If you order stop, you will drift. If you order speed of current in oposite direction of the current, you will stop.

How does sub measure speed IRL I don't know. They can't use GPS (which could give speed agains ground). The most probably have some inercial position (thus speed) system, but how precise that can be ? Who knows ..

Aircrafts uses mainly speed against air, but hey can easily read speed against ground via GPS (and they do), same for surface ships.

Mau · 02-12-06, 08:52 AM

I will have to check this.

Did you tried to have some chaff/flare in the air to see the effect of 1.03 on it?

Mau · 02-12-06, 09:43 AM

I think the effect of wind (RL), compared to the effect of current, is in the order of 1 to 5 (have to double check) for the current.

Dr.Sid · 02-12-06, 10:15 AM

I guess the effect of wind must be affected by many factors. It would affect the ship less from the front then from the side. It would vary a lot for different ships based on above water - under water surface ratio.
Not that we need any accurate simulation of winds anyway. But now it is really wierd.

Mau · 02-12-06, 12:41 PM

Yes we need wind and current to works (at least that it behave properly) so that if we have stronger wind/current we will feel it on the ship and consideration to be taken for chaff/flare when being launch so that we will not create Fly Up/Fly through situation (which cause the loss of the Atlantic Conveyor during the Falklands War)

moose1am · 02-12-06, 01:14 PM

I think you will drift at all stop with a current or even with a high winds. IRL you sure would.

Last night while playing DW I was trying to figure out how fast a surface ship was going using the DEMON. I could not get the DEMON to show lines on the display. I worked on this for a long time and nothing seemed to work. It was at the end of a quick mission and the ship was one of my own.

I finally turned on the "show truth" and it showed the ship moving at 1mph. However there were no blades turning.

I think this is what happened. The ship was at all stop and drifting at 1mph. I was within 2.1 nm of the ship and using the forward spherical array to listen to the ships sounds. I was going less then 5 K also.

Quote:

Originally Posted by Three14

Been wondering this for awhile...

If you order all stop, will you drift? Or, put another way, is there a way to get the boat to drift with the current and another way to make sure it stays put?

02-12-06, 05:43 AM	#1
Dr.Sid The Old Man Join Date: May 2005 Location: Czech Republic Posts: 1,458 Downloads: 6 Uploads: 0	Wind and currents troubles with 1.03 Well .. there is no change in currents, they are still the same. Which means almost useless. Currents work like this: they add specific vector (of the current) to the ship speed. That's all. It means for example that if there is 3kts current and the sub goes 10 knots in the same direction, it will loose periscope, because total sub speed will be 13 knots. In reality speed of the sub against the water is still 10 kts, so there should be no problem. Currents also don't affect towed arrays, so it's quite easy to loose it with strong currents. On the other hand, strong currents are rare in the seas and so in the custom made scenarios, so you will loose nothing if you simply turn the currents off. There seems to be bigger problem with winds in 1.03 (I did not noticed this with older versions). Wind works exactly like the currents except that it works on aircraft. Here it is not much problem, because there are not so tight speed limits, and the wind should not affect hydrophone while it is in the water (but currents shoudl !). But the wind in 1.03 seems to affect surface ships too ! In exactly the same way ! It means if you have 5 kts wind, and you turn OHP agains the wind and order 5kts, you will stand dead in the watter. Problem is that many scenarios use at least weak wind which now affects heavily especially OHP performace. You can easily get into negative speed, and if you move slow, it's hard to get where you wanted to go. Fast fix is of course to switch winds off too.

02-12-06, 07:28 AM	#2
Three14 Seaman Join Date: Feb 2001 Location: Hong Kong Posts: 39 Downloads: 0 Uploads: 0	Been wondering this for awhile... If you order all stop, will you drift? Or, put another way, is there a way to get the boat to drift with the current and another way to make sure it stays put?

02-12-06, 08:40 AM	#3
Dr.Sid The Old Man Join Date: May 2005 Location: Czech Republic Posts: 1,458 Downloads: 6 Uploads: 0	You always order speed agains water (air) .. not agains ground. If you order stop, you will drift. If you order speed of current in oposite direction of the current, you will stop. How does sub measure speed IRL I don't know. They can't use GPS (which could give speed agains ground). The most probably have some inercial position (thus speed) system, but how precise that can be ? Who knows .. Aircrafts uses mainly speed against air, but hey can easily read speed against ground via GPS (and they do), same for surface ships.

02-12-06, 08:52 AM	#4
Mau Sonar Guy Join Date: Jun 2005 Posts: 382 Downloads: 3 Uploads: 0	I will have to check this. Did you tried to have some chaff/flare in the air to see the effect of 1.03 on it?

02-12-06, 09:43 AM	#5
Mau Sonar Guy Join Date: Jun 2005 Posts: 382 Downloads: 3 Uploads: 0	I think the effect of wind (RL), compared to the effect of current, is in the order of 1 to 5 (have to double check) for the current.

02-12-06, 10:15 AM	#6
Dr.Sid The Old Man Join Date: May 2005 Location: Czech Republic Posts: 1,458 Downloads: 6 Uploads: 0	I guess the effect of wind must be affected by many factors. It would affect the ship less from the front then from the side. It would vary a lot for different ships based on above water - under water surface ratio. Not that we need any accurate simulation of winds anyway. But now it is really wierd.

02-12-06, 12:41 PM	#7
Mau Sonar Guy Join Date: Jun 2005 Posts: 382 Downloads: 3 Uploads: 0	Yes we need wind and current to works (at least that it behave properly) so that if we have stronger wind/current we will feel it on the ship and consideration to be taken for chaff/flare when being launch so that we will not create Fly Up/Fly through situation (which cause the loss of the Atlantic Conveyor during the Falklands War)