SH4 Plotting Board

[muser]

Here's a plotting board for any of you that might like to track your targets in Silent Hunter IV the good old fashioned way -- pencil and paper. It's scaled in yards and nautical miles, and will print a very clean image at up to 20" x 24".

20" x 24" Silent Hunter IV version with distance scales in yards and nautical miles:
(The actual image quality is much better than seen here.)
http://hoist.hrtc.net/~standsapart/SH3/plotboardYards.jpg



You can download the Silent Hunter IV version here:
http://files.filefront.com/plotboard_yards_20_x_24jpg/;6847891;;/fileinfo.html

A link to chapter six of the pub 1310 plotting manual (explains how to use the maneuvering board):
http://files.filefront.com/plotting_manual_pub_1310zip/;6831920;;/fileinfo.html



A meters and kilometers version for SHIII can be found at this post:
http://www.subsim.com/radioroom/showpost.php?p=430253&postcount=1

[geetrue]

This is for radar ... right? You need other items to determine range ... sonar will only give you realitive bearings, not range.

Still need a compass looking slideboard that calculates kts. bearing/angle on the bow ... based on estimated or real time range.

Thanks for the chart :yep:

[Tigrone]

Very nice Muser, and much more real than the graph paper, I've been using.

[muser]

geetrue,

Right you are. As far as I know, the form was originally used for plotting target information transferred from the radar scope.

In my case, I plot the tagets relative position and movement; based on observations of time, bearing, and range with the UZO or periscope.

By the way, this is a pretty good tool for teaching a budding navigator a little applied geometry and trig. See this post:
http://www.subsim.com/radioroom/showpost.php?p=430253&postcount=1

[Snowman999]

Right you are. As far as I know, the form was originally used for plotting target information transferred from the radar scope.


Not trying to teach the navy vets to suck eggs, but the rest might be interested to know that this plotting device is still used--intact from 1920--in CICs and submarine control rooms today. Throughout the USN it's known as a "mo-board". When I went through OCS in 1980 we had to learn celestial nav, inshore piloting/chart work, and mo board. It's used most often as a very quick aid to determine one of three things: 1) a contact's true course and speed and thus an intercept or avoidance course for own ship, 2) a contact's closest-point-of-approach to own ship (CPA), and 3) an own-ship true course needed to be steered relative to another (usiually a carrier) in order to take up a new position in the screen or to plane-guard.

Own ship is in the center. One always knows own ship course and speed, which gives a vector. A target bearing and range is marked in at least two data points, with time between observations (usualy 3-minutes so the 3-Minute Rule applies) known. A line is drawn between the two points, that line is "walked" to the end of own ship's vector with parallel rulers, and a third vector to close the triangle is the target course and speed. It's just a relative motion working tool.

Radar is normally the primary data colleciton tool since every CO has standing orders to the OOD when to maneuver to avoid a CPA of "x", and waiting until accurate visual range (stadimenter in scope or handheld) is available results in CPAs far too close for any CO to accept. But I've done mo board re-verifications through the scope when I was contact coordinator to back up the PPI data and ensure the contact didn't maneuver too close.

Normally in my day, on the surface, there's an ET manning the radar and ESM, moving between them, and he does a mo board on the PPI with a grease pencil to back up the contact coordinator's pencil version. The OOD on the bridge is often doing a mental mo board as well (he'd better be ; it's his butt in the sling.) You can usually tell how long somebody has been conning when they don't need the paper, but most COs I've known insist on the discipline. Most/all OODs also do rough mo boards on the PPI using fingers to "walk" the contact vectors and get a good-enough answer in under five seconds.

In the USN anywhere vessels are moving you'll find pads of mo board paper, dividers, and parallel rulers. Staying with yards/nms makes the 3-minute math easy as well. Mo boards are the most basic tool for avoiding collisions at sea we have. The paper shown in this thread hasn't changed since 1920 because it's perfect as is, but its age is irrelevant to its usefulness. Running a mo board is truly an entry-level skill for all officers, mids, QMs, ETs, sonar girls, etc.

Final aside--I've never seen a mo board attempted to be used in a passive environment, either sonar or emcon, since you do need a range to match with the bearing. TMA (target-motion-analysis) is used in passive situations and range falls out of that process. It's not an input.

[geetrue]

Not trying to teach the navy vets to suck eggs, but the rest might be interested to know that this plotting device is still used today. When I went through OCS in 1980 we had to learn celestial nav, inshore piloting/chart work, and mo board.
Running a mo board is truly an entry-level skill for all officers, mids, QMs, ETs, sonar girls, etc.

sonar girls! Sir, an officer in the USN submarine service is considered a gentleman.

Your cruising for a bruising ... sir! :o

[Snowman999]

sonar girls! Sir, an officer in the USN submarine service is considered a gentleman.

Your cruising for a bruising ... sir! :o


VBG.

Sorry, but that's what they're universally called. Probably has something to do with their excitability ("The plane, boss! The plane!!!) and showering habits (long and hot--you can get pretty stinky working in that 50-degree blue cave. <g>) Their water consumption always gave A-gang an excuse to not shower at all--and they really, REALLY needed to.

FWIW, I'm the son of a chief sonarman, qualified in diesel boats (in a very famous diesel boat in fact, one that sank a Japanese CL. Hope it's in the game.)

[muser]

Not trying to teach the navy vets to suck eggs, but the rest might be interested to know that this plotting device is still used--intact from 1920--in CICs and submarine control rooms today. Throughout the USN it's known as a "mo-board". When I went through OCS in 1980 we had to learn celestial nav, inshore piloting/chart work, and mo board. It's used most often as a very quick aid to determine one of three things: 1) a contact's true course and speed and thus an intercept or avoidance course for own ship, 2) a contact's closest-point-of-approach to own ship (CPA), and 3) an own-ship true course needed to be steered relative to another (usiually a carrier) in order to take up a new position in the screen or to plane-guard.

Snowman999,

Thanks for the informative post on the use of the "mo-board" -- a very interesting read.