Visual Measurement of Very Long Range Distances

ColonelSandersLite · 01-01-13, 05:31 AM

Before continuring, I'd like to say that thoughts are welcome. If you have a better way, please let me know.

Ok, so the problem is: how does one get distance measurements on a distant target *BEFORE RADAR* is available. This can be pretty important when trying to set up an attack on an escorted convoy for example.

Alright, here's what I've come up with, after some reading, critical thinking, and math. In a nutshell, you can measure the distance to a target at very long range using the horizontal scale on the periscope and tbt. Using this method, I can get measurements that are reasonably accurate (+/- about 200 yards) on a target that is 5 miles away.

As we all (probably) know, the standard method up close is to use mast height and either the stadimeter or vertical hash marks as can be seen here:
http://img398.imageshack.us/img398/2958/plateiiawg1.jpg

The problem with this method at long range is that you cannot necessarily see the waterline of a ship at long range due to the curvature of the earth (which is modeled in sh4) so I got to thinking, what if you use the horizontal hashes instead?

The steps to follow:

1: You must be at or near a 90 degree aob from the target, so shadow the target and pull even with it.

2: Measure the targets length using the horizontal hash marks.

3: Reference ship length and do some math.

The following is what I have come up with for tmo 2.5. Depending on how the game displays, it may be relevent that I'm using a 16X9 Resolution.

Code:

   Periscope - High Zoom                                   TBT

           277.63*Ship Length                          515.58*Ship Length
Distance = ------------------               Distance = ------------------
               Hash Marks                                  Hash Marks

Ship Name       Length - Yards               Ship Name       Length - Yards

Japanese DDs & Escorts--------               Merchants---------------------     
Auxilary Subchaser       68.90               AKITA MARU              114.83
Akikaze Destroyer       112.10               BIYO MARU               131.23
Akizuki Destroyer       147.64               British Med Old Tanker  100.07
Asashio Destroyer       129.05               BUZYUN MARU             112.64
Etorofu Escort           72.18               Coastal Comp Freighter   88.33
Fubuki Destroyer        129.59               Conte Verde Liner       190.00
Kisaragi Destroyer      111.55               HAKUSIKA MARU           147.64
Minekaze Destroyer      112.20               HARUNA MARU              83.11
Momi Destroyer          112.20               HEITO MARU              113.30
Mutsuki Destroyer       111.55               Hog Island typ A Frghtr 131.23
Shiratsuyu Destroyer    118.11               HORAI MARU              150.33
Somers Destroyer        126.86               KASAGISAN MARU           94.93
Type C Escort            97.88               KINPOSAN MARU           118.11
Type D Escort            97.88               KITURIN MARU            142.17
Shimushu Escort          76.55               Landing Ship Tank       107.94
Wakatake Destroyer      112.20               Large German Tanker     207.79
Yugumo Destroyer        129.05               Liberty Cargo           160.76
                                             Medium Modern Passenger 114.83
Japanese Carriers-------------               MOMOYAMA MARU           131.23
Akitsu Escort Carrier   157.21               NAGARA MARU             149.82
Chitose Seaplane Tender 210.52               NIPPON MARU             164.04
Hiryu Fleet Carrier     244.20               Old Raked Bow Split     131.23
Shokaku Fleet Carrier   273.40               RYUUN MARU              131.23
Taiho Fleet Carrier     277.45               Small Old Split Frghtr   88.04
Taiyo Escort Carrier    196.96               Small Split Freighter    95.00
                                             T3 Tanker               207.79
Japanese BBs and Cruisers-----               TAIHOSAN MARU            88.04
Agano Light Cruiser     191.38               Troop Transport         166.23
Furutaka Heavy Cruiser  205.60               TYOHEI MARU              86.40
Fuso Battleship         231.85               Victory Cargo           152.67
Ise Battleship          240.59               ZINBU MARU              131.23
Kongo Battleship        240.59                    
Kuma Light Cruiser      178.26               Japanese Others---------------     
Maya Heavy Cruiser      223.10               Atami Gunboat            49.21
Mogami Heavy Cruiser    218.72               Hira Gunboat             60.15
Naka Light Cruiser      177.16               Okinoshima Minelayer    134.95
Takao Heavy Cruiser     223.10
Yamato Battleship       287.62

If you're not using TMO, the ship lengths can be gotten with http://www.subsim.com/radioroom/down...o=file&id=1602

I took these steps to determine the constant.

Set up a single mission with a couple of stationary vessels.

Start the mission with map contacts set to on, so that you can measure the distance to target on the map. Radar could be used instead.

Count the number of hash marks the target takes up and plug the data into this formula.

Constant to use = (Distance X Hash Marks) / Ship Length

Recommendations:
When deriving the constant, close to the point where the sample vessel takes up all the hash marks. Try to avoid fractions (IE 8.5 hash marks).

Test it on a few different vessels, not just one. I can't say with any certainty that all the measurements the game spits out are actually correct.

Make sure you're at 90 degrees AOB.

Test it at a few different ranges to make sure you got it right.

If you're plotting in yards, be sure that the ship lengths are converted from meters to yards. The game's values are metric so Gutted's utility will also spit out metric values.

01-01-13, 05:31 AM	#1
ColonelSandersLite Captain Join Date: Aug 2009 Posts: 481 Downloads: 74 Uploads: 3	Visual Measurement of Very Long Range Distances Before continuring, I'd like to say that thoughts are welcome. If you have a better way, please let me know. Ok, so the problem is: how does one get distance measurements on a distant target BEFORE RADAR is available. This can be pretty important when trying to set up an attack on an escorted convoy for example. Alright, here's what I've come up with, after some reading, critical thinking, and math. In a nutshell, you can measure the distance to a target at very long range using the horizontal scale on the periscope and tbt. Using this method, I can get measurements that are reasonably accurate (+/- about 200 yards) on a target that is 5 miles away. As we all (probably) know, the standard method up close is to use mast height and either the stadimeter or vertical hash marks as can be seen here: http://img398.imageshack.us/img398/2958/plateiiawg1.jpg The problem with this method at long range is that you cannot necessarily see the waterline of a ship at long range due to the curvature of the earth (which is modeled in sh4) so I got to thinking, what if you use the horizontal hashes instead? The steps to follow: 1: You must be at or near a 90 degree aob from the target, so shadow the target and pull even with it. 2: Measure the targets length using the horizontal hash marks. 3: Reference ship length and do some math. The following is what I have come up with for tmo 2.5. Depending on how the game displays, it may be relevent that I'm using a 16X9 Resolution. Code: Periscope - High Zoom TBT 277.63Ship Length 515.58Ship Length Distance = ------------------ Distance = ------------------ Hash Marks Hash Marks Ship Name Length - Yards Ship Name Length - Yards Japanese DDs & Escorts-------- Merchants--------------------- Auxilary Subchaser 68.90 AKITA MARU 114.83 Akikaze Destroyer 112.10 BIYO MARU 131.23 Akizuki Destroyer 147.64 British Med Old Tanker 100.07 Asashio Destroyer 129.05 BUZYUN MARU 112.64 Etorofu Escort 72.18 Coastal Comp Freighter 88.33 Fubuki Destroyer 129.59 Conte Verde Liner 190.00 Kisaragi Destroyer 111.55 HAKUSIKA MARU 147.64 Minekaze Destroyer 112.20 HARUNA MARU 83.11 Momi Destroyer 112.20 HEITO MARU 113.30 Mutsuki Destroyer 111.55 Hog Island typ A Frghtr 131.23 Shiratsuyu Destroyer 118.11 HORAI MARU 150.33 Somers Destroyer 126.86 KASAGISAN MARU 94.93 Type C Escort 97.88 KINPOSAN MARU 118.11 Type D Escort 97.88 KITURIN MARU 142.17 Shimushu Escort 76.55 Landing Ship Tank 107.94 Wakatake Destroyer 112.20 Large German Tanker 207.79 Yugumo Destroyer 129.05 Liberty Cargo 160.76 Medium Modern Passenger 114.83 Japanese Carriers------------- MOMOYAMA MARU 131.23 Akitsu Escort Carrier 157.21 NAGARA MARU 149.82 Chitose Seaplane Tender 210.52 NIPPON MARU 164.04 Hiryu Fleet Carrier 244.20 Old Raked Bow Split 131.23 Shokaku Fleet Carrier 273.40 RYUUN MARU 131.23 Taiho Fleet Carrier 277.45 Small Old Split Frghtr 88.04 Taiyo Escort Carrier 196.96 Small Split Freighter 95.00 T3 Tanker 207.79 Japanese BBs and Cruisers----- TAIHOSAN MARU 88.04 Agano Light Cruiser 191.38 Troop Transport 166.23 Furutaka Heavy Cruiser 205.60 TYOHEI MARU 86.40 Fuso Battleship 231.85 Victory Cargo 152.67 Ise Battleship 240.59 ZINBU MARU 131.23 Kongo Battleship 240.59 Kuma Light Cruiser 178.26 Japanese Others--------------- Maya Heavy Cruiser 223.10 Atami Gunboat 49.21 Mogami Heavy Cruiser 218.72 Hira Gunboat 60.15 Naka Light Cruiser 177.16 Okinoshima Minelayer 134.95 Takao Heavy Cruiser 223.10 Yamato Battleship 287.62 If you're not using TMO, the ship lengths can be gotten with http://www.subsim.com/radioroom/down...o=file&id=1602 I took these steps to determine the constant. Set up a single mission with a couple of stationary vessels. Start the mission with map contacts set to on, so that you can measure the distance to target on the map. Radar could be used instead. Count the number of hash marks the target takes up and plug the data into this formula. Constant to use = (Distance X Hash Marks) / Ship Length Recommendations: When deriving the constant, close to the point where the sample vessel takes up all the hash marks. Try to avoid fractions (IE 8.5 hash marks). Test it on a few different vessels, not just one. I can't say with any certainty that all the measurements the game spits out are actually correct. Make sure you're at 90 degrees AOB. Test it at a few different ranges to make sure you got it right. If you're plotting in yards, be sure that the ship lengths are converted from meters to yards. The game's values are metric so Gutted's utility will also spit out metric values.