Shadowing convoy with hydrophones

Pisces · 03-09-11, 06:36 AM

It's quite impossible to get any reliable course from 3 bearings taken of a convoy, since you can't get a clear indication of individual sounds. So forget that. Heading straight for them in the direction of the sound is also quite risky because if you come from somewhere head-on of them then you have a high relative motion. And subsequently hardly have any time to slow down before you get into their engage range.

As a solution I suggest to go in a direction that is a certain amount of degrees lagging to the bearing drift of the 'last' convoy sound. This allways get's you behind it. As it moves forward the bearings slip in left or right direction. Steer about 20 degrees behind it, and keep adjusting course. (not a fixed important value, just a rule of thumb) Sooner or later you are behind them and creeping up their tail if your speed isn't too high. (upper limit of the reported speed-range should be good) Then your relative speed is alot less (the difference of both your speeds) and you get more time to react as they are getting visual. If the bearing seems to change more rapidly then be carefull, then you are quite close. From then on just follow them until better weather comes along. But keep in mind that weather can change on a dime, so this instant you have fog, and the next you're spotted. So it's better to keep them between long and medium range by adjusting your speed up and down over the hours. It's going to be an arduous, long and nerve-wrecking task.

kapuhy · 03-09-11, 07:47 AM

Quote:

Originally Posted by Pisces

an arduous, long and nerve-wrecking task.

- a.k.a. commanding a WW2 submarine.

Thanks for the advice, I'll try that.

Gerald · 03-09-11, 10:15 AM

Shadowing convoy with hydro-phones, what was your title, so of course it is time consuming but not impossible, but everything should be done in real-time

03-09-11, 06:36 AM	#1
Pisces Silent Hunter Join Date: Dec 2004 Location: AN9771 Posts: 4,904 Downloads: 304 Uploads: 0	It's quite impossible to get any reliable course from 3 bearings taken of a convoy, since you can't get a clear indication of individual sounds. So forget that. Heading straight for them in the direction of the sound is also quite risky because if you come from somewhere head-on of them then you have a high relative motion. And subsequently hardly have any time to slow down before you get into their engage range. As a solution I suggest to go in a direction that is a certain amount of degrees lagging to the bearing drift of the 'last' convoy sound. This allways get's you behind it. As it moves forward the bearings slip in left or right direction. Steer about 20 degrees behind it, and keep adjusting course. (not a fixed important value, just a rule of thumb) Sooner or later you are behind them and creeping up their tail if your speed isn't too high. (upper limit of the reported speed-range should be good) Then your relative speed is alot less (the difference of both your speeds) and you get more time to react as they are getting visual. If the bearing seems to change more rapidly then be carefull, then you are quite close. From then on just follow them until better weather comes along. But keep in mind that weather can change on a dime, so this instant you have fog, and the next you're spotted. So it's better to keep them between long and medium range by adjusting your speed up and down over the hours. It's going to be an arduous, long and nerve-wrecking task. __________________ My site downloads: https://ricojansen.nl/downloads

03-09-11, 10:15 AM	#3
Gerald SUBSIM Newsman Join Date: May 2008 Location: Close to sea Posts: 24,254 Downloads: 553 Uploads: 0	Shadowing convoy with hydro-phones, what was your title, so of course it is time consuming but not impossible, but everything should be done in real-time __________________ Nothing in life is to be feard,it is only to be understood. Marie Curie