How to use periscope marks?

Gino · 01-12-08, 06:53 PM

These reticle scales are the basic means for determining target range. On COD's periscopes, on L.P. (low-power) each scale mark represents 1-degree of optical angle. On H.P. the longer marks are 1-degree apart and each shorter mark is 1/4-degree. Knowing that at 1000 yards range, a length of 52.5 feet subtends an angle of 1-degree provides you with a means for converting known lengths to range. It would be tough to do all but the simple calculations in your head, but the Range Omnimeter

is one example of a quick tool for determining range using these reticle marks. If the attack officer knows the masthead height of a target and sets this value on the Omnimeter, he can then observe the relative optical height of the mast in terms of scale divisions and then read off the range to the target directly from the Omnimeter.

For example, if I know that a ship's masthead height is 70 feet and it appears to take up three reticle marks on the vertical scale with the scope set on H.P. then I can immediately read from the Omnimeter that the target's range must be 1860 yards.

The horizontal reticle scale can be used in the same way using a target's known waterline length and estimated angle on the bow. Or the two ideas can be used together to first find the range, then observe the apparent waterline length, and then read the angle on the bow directly from the Omnimeter.

Other example:

I guess someone's gonna build this one next...
Need more info?

Likewise:

groetjes,

Q3ark · 01-13-08, 07:11 AM

Very interesting thanks for the info Gino. Wonder if this works correctly in game I think some testing is in order after work tonight.

Blue · 01-13-08, 06:47 PM

While reading, I just realized a new question.......

When using the Stadimeter is it nescassary to align the scope's horizontal center-line with the horizon or surf. line? I see that proper alignment is obviously required when calculating range manually. Does it matter with the Stadimeter?

Q3ark · 01-13-08, 06:58 PM

Quote:

Originally Posted by Blue

While reading, I just realized a new question.......

When using the Stadimeter is it nescassary to align the scope's horizontal center-line with the horizon or surf. line? I see that proper alignment is obviously required when calculating range manually. Does it matter with the Stadimeter?

No you don't have to line up the horizontal line with the waterline on the ship. It'll work just fine

01-12-08, 06:53 PM	#1
Gino Pacific Sub Expert Join Date: Aug 2006 Location: Las Vegas, Nevada Posts: 148 Downloads: 56 Uploads: 0	These reticle scales are the basic means for determining target range. On COD's periscopes, on L.P. (low-power) each scale mark represents 1-degree of optical angle. On H.P. the longer marks are 1-degree apart and each shorter mark is 1/4-degree. Knowing that at 1000 yards range, a length of 52.5 feet subtends an angle of 1-degree provides you with a means for converting known lengths to range. It would be tough to do all but the simple calculations in your head, but the Range Omnimeter is one example of a quick tool for determining range using these reticle marks. If the attack officer knows the masthead height of a target and sets this value on the Omnimeter, he can then observe the relative optical height of the mast in terms of scale divisions and then read off the range to the target directly from the Omnimeter. For example, if I know that a ship's masthead height is 70 feet and it appears to take up three reticle marks on the vertical scale with the scope set on H.P. then I can immediately read from the Omnimeter that the target's range must be 1860 yards. The horizontal reticle scale can be used in the same way using a target's known waterline length and estimated angle on the bow. Or the two ideas can be used together to first find the range, then observe the apparent waterline length, and then read the angle on the bow directly from the Omnimeter. Other example: I guess someone's gonna build this one next... Need more info? Likewise: groetjes, __________________ Gino

01-13-08, 07:11 AM	#2
Q3ark Watch Officer Join Date: Apr 2007 Location: York, England Posts: 346 Downloads: 47 Uploads: 0	Very interesting thanks for the info Gino. Wonder if this works correctly in game I think some testing is in order after work tonight. __________________ Johnny was a chemist's son, But Johnny is no more. What Johnny thought was H20 was H2SO4.

01-13-08, 06:47 PM	#3
Blue Watch Join Date: Dec 2007 Location: New York Posts: 15 Downloads: 23 Uploads: 0	While reading, I just realized a new question....... When using the Stadimeter is it nescassary to align the scope's horizontal center-line with the horizon or surf. line? I see that proper alignment is obviously required when calculating range manually. Does it matter with the Stadimeter?