Newbie question

[Jethro13]

Hey there, thanks for the help with the following :

When you get a contact report from the hydrophone (i.e contact, mechant moving slow, bearing 90 degrees), the bearing that is given is the direction you have to go to intercept right ? just a bit confused about all this...I keep missing the ships. Any clarifications in how I need to react to intercept would be much appreciated..

'Later !

[_Seth_]

Hi mate, and welcome to the best forum ever!
If i understand you correct: Yes, the sonar man calls out the bearing according to your uboat, IE your bow is 000 degress all the time.

[mr chris]

Yep if the sonar guy shouts contact at 300 It will be at 300d in your Scope.

[bigboywooly]

The bearing given is relative to your position

If you are travelling North - 0 degrees and get a contact at 90 degrees then the contact is East
However if you are travelling East - 90 degrees - and the contact is 90 degrees then the contact is South - 180 degrees

[Mooncatt]

Originally Posted by Jethro13

Hey there, thanks for the help with the following :

When you get a contact report from the hydrophone (i.e contact, mechant moving slow, bearing 90 degrees), the bearing that is given is the direction you have to go to intercept right ? just a bit confused about all this...I keep missing the ships. Any clarifications in how I need to react to intercept would be much appreciated..

'Later !

hi m8 and welcome.
the 90 degree angle is just the direction of the ship in relation to your u-boat thats all.
im no good at explaining the intercept process you should use all i would do is confuse you. there are better people here that could explain better than me lol
gl

Originally Posted by Jethro13

Hey there, thanks for the help with the following :

When you get a contact report from the hydrophone (i.e contact, mechant moving slow, bearing 90 degrees), the bearing that is given is the direction you have to go to intercept right ? just a bit confused about all this...I keep missing the ships. Any clarifications in how I need to react to intercept would be much appreciated..

'Later !

The contact report bearing is not the direction you need to go to intercept. It's simply the direction the contact is, located relative to you, at that moment in time. I'll try to explain a little:

Picture an analog clock face. You (your boat) is located dead-center of the clock, at the clock hands center, bow facing 12 o'clock. You get a sound contact at 270 degrees; that locates the sound direction at the 9 position of the clock. Simple so far.

However, that sound contact is also moving. Unless it is heading directly towards or away from you, if you just set your course to 270 degrees, by the time you reach where the sound contact was it's gone.

You can get a heading of it's movement by taking consecutive sound checks and marking their bearings. For instance, three checks, 10 minutes apart, are recorded as 110, 110, 110. That means it's heading either directly towards or away from you, and your SO should be able to clarify that with 'moving away' or 'closing'.

It gets more difficult when they are moving at an angle relative to you, because the hydrophone does not give a precise distance along with the bearing. You can still get a reasonable idea if you again take three consecutive sound checks 10 minutes apart (or less, depending on how close and/or fast they are). Listen on your hydrophone and take a guesstimate on their range -- loud: 3km ; medium: 8km ; soft: 15km. Now plot each bearing you've taken with those distances.

Say you've taken three sound checks and have gotten 85, 82 and 79 degrees. Listening to the sounds you rate them as medium. From your location plot three lines at those angle bearings, each 8km long. Mark the endpoints, then draw a line through them. This gives you the contacts approximate course.

That should be sufficient for you to plot an intercept.

[Brag]

Welcome aboard!
You may want to take a look at the posting: approaching a convoy with periscope down (it should be in the second page of this forum, there is sceenie there where the course of a destroyer is plotten. This may help you clarify how to plot a sound contact.

Besties,

[Jethro13]

Thanks for all the help guys ! ! !

I'll try it and see how it goes, i'll post again if I'm still missing them but I should be all set...

Happy hunting !