SUBSIM Radio Room Forums - View Single Post - Submarine Attack Course Finder (a.k.a. Is-Was / Banjo)

Igorry · 04-15-07, 09:39 AM

I like give my 2 cents worth on how to use the Is-was/banjo using cpt krunch example.

The Is-was/banjo has 4 dial

A dial is the submarine
B dial is the true compass
C dial is the periscope ruler
D dial is the enemy ship

The banjo can used to find the AOB of the enemy ship or the course of the enemy ship. However in each case three piece of information is required.

1) TO FIND AOB OF ENEMY SHIP

Three piece of information is require - your sub course, the relative bearing, the enemy course

a) Our sub course is 90 degree east.

According to cpt Krunch, he align B dial 90 degree to A dial at 0 degree.
I disagree that is the right procedure.

I think you should align B dial 90 degree to A dial at 180 degree. The triangle protruding out of the A dial is always the submarine bow and the opposite semicircle in dial A is the submarine stern.

b) From the periscope we spotted a ship and the relative bearing is 300 degree.

This is the same as capt Krunch. Move the periscope tab or c dial so that the outer marker in the periscope tab is over the A dial at 300 degree mark. Note in the periscope tab, there are two markers. One is pointing to A dial and the other is pointing to D Dial.

c) We have a contact heading 330 degree.

Move the D dial 0 degree (which represents the bow of the enemy ship) to B dial at 330 degree. (B dial is the true compass)

When you have done this, you can find AOB easily by reading from the periscope tab, the inner marker which points to the D dial at 120 degree port.

2) TO FIND THE COURSE OF ENEMY SHIP

Three piece of information required: The sub course, the relative bearing and the estimated AOB

a) Our sub course is 55 degree.

B dial 55 degree to A dial at 180 degree. The triangle protruding out of the A dial is always the submarine bow and the opposite semicircle in dial A is the submarine stern.

b) From the periscope we spotted a ship and the relative bearing is 260 degree.

Move the periscope tab or c dial so that the outer marker in the periscope tab is over the A dial at 260 degree.

c) Estimated AOB is 45 degree starboard.

Move the D dial starboard 45 degree to the inner marker of the periscope tab. At this point the outer marker is pointing to 260 degree of A dial and inner marker is pointing to D dial at 45 degree starboard.

To find the course of ship, read the 0 degree of D dial (which is the bow of the enemy ship) to B dial. You will find the enemy course to be 90 degree.

I hope I have not confuse the picture further. My only difference is that I believe the 180 degree in A dial is the bow of the sub where as the 0 degree is the stern of the sub.

Igorry

04-15-07, 09:39 AM	#39
Igorry Swabbie Join Date: Dec 2004 Posts: 10 Downloads: 23 Uploads: 0	I like give my 2 cents worth on how to use the Is-was/banjo using cpt krunch example. The Is-was/banjo has 4 dial A dial is the submarine B dial is the true compass C dial is the periscope ruler D dial is the enemy ship The banjo can used to find the AOB of the enemy ship or the course of the enemy ship. However in each case three piece of information is required. 1) TO FIND AOB OF ENEMY SHIP Three piece of information is require - your sub course, the relative bearing, the enemy course a) Our sub course is 90 degree east. According to cpt Krunch, he align B dial 90 degree to A dial at 0 degree. I disagree that is the right procedure. I think you should align B dial 90 degree to A dial at 180 degree. The triangle protruding out of the A dial is always the submarine bow and the opposite semicircle in dial A is the submarine stern. b) From the periscope we spotted a ship and the relative bearing is 300 degree. This is the same as capt Krunch. Move the periscope tab or c dial so that the outer marker in the periscope tab is over the A dial at 300 degree mark. Note in the periscope tab, there are two markers. One is pointing to A dial and the other is pointing to D Dial. c) We have a contact heading 330 degree. Move the D dial 0 degree (which represents the bow of the enemy ship) to B dial at 330 degree. (B dial is the true compass) When you have done this, you can find AOB easily by reading from the periscope tab, the inner marker which points to the D dial at 120 degree port. 2) TO FIND THE COURSE OF ENEMY SHIP Three piece of information required: The sub course, the relative bearing and the estimated AOB a) Our sub course is 55 degree. B dial 55 degree to A dial at 180 degree. The triangle protruding out of the A dial is always the submarine bow and the opposite semicircle in dial A is the submarine stern. b) From the periscope we spotted a ship and the relative bearing is 260 degree. Move the periscope tab or c dial so that the outer marker in the periscope tab is over the A dial at 260 degree. c) Estimated AOB is 45 degree starboard. Move the D dial starboard 45 degree to the inner marker of the periscope tab. At this point the outer marker is pointing to 260 degree of A dial and inner marker is pointing to D dial at 45 degree starboard. To find the course of ship, read the 0 degree of D dial (which is the bow of the enemy ship) to B dial. You will find the enemy course to be 90 degree. I hope I have not confuse the picture further. My only difference is that I believe the 180 degree in A dial is the bow of the sub where as the 0 degree is the stern of the sub. Igorry