Thread by @AdroitlyAbsurd

Tempting as it is to assume this is a clock, it couldn’t be. After all, if it WAS a clock on a French ship there would be a heck of a lot of ormolu dripping off the thing...

What time is it? Range finder time!

🔭🕓⛴🧵

/1

https://twitter.com/thedreadships/status/1321791396471332865

In grand naval tradition up to WWII, typical line-of-battle was just that: LINE of battle. Ships stem to stern, firing broadside

In ye olde days before yer fancy radar or radio (wireless, for you old-schoolers), how do you get all the ships firing on the same target? SIGNALS! /2

As an aside, “Broadside” is the literal name of the game, as in “what’s one of your favorite early 1960s War of 1812-themed naval combat board games where you get to dismast your opponent while showering them w/ 19th century sailor’s profanity?”

boardgamegeek.com/boardgame/1508… /3

Anyway, yelling or using noisemakers from drums & whistles to cannon fire for signals gets confusing quick, as naval engagements tend to be Loud Events.

Semaphore signals are good, but time consuming. Even raising flags can take time, let alone hand signaling. /4

Signal lamps became popular, particularly after electricity became practical, but as anyone whom has ever tried to put on a performance of “Julius Caesar” w/ an Aldis lamp knows, this too takes time.

And yes, this photo was already downloaded on my phone. /5

Weather & pesky side-effects of battle such as smoke, splashes, & overwhelming disorientation do tend to make these visual signals hit-or-miss, w/ missing part of the message having rather *severe* consequences. /6

Thus, the Range (or Concentration) Dial was born. Easier to read than earlier “drums,” two hands could indicate numbers representing 100s (hour hand) or 1,000s of yds (minute hand). Extra indicators could add 100,000s of yds.

Dial faces ranged (hah!) from 4-10 ft. in diameter /7

For quick reading the “hour” & “minute” hands were colored (ex: red or blue) & had “spoons” attached to the ends in different shapes (ex: circle or diamond)

Most dial faces were white w/ black numbers, although some (see previous pics) bucked the trend b/c of course they did

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Here’s designs from the British Royal Navy (Roman Numerals? How posh!): dreadnoughtproject.org/tfs/index.php/…

The dials numbered above “9” are for numeric signal codes; otherwise, “0” indicates the base number (100, 1,000, etc.). /9

So, this example shows a target range of 150 yds (“minute” hand), 8,000 yds (“hour” hand), & 10,000 yds (black dot aligned w/ “I”), or 18,150 yds. /10

These indicators worked using the same technology as Engine Order Telegraphs, as demonstrated in this BBC clip of Ruth Goodman aboard the 1924 paddle steamer PS Kingswear Castle on the River Dart: /11

Engine Order Telegraphs are beautiful examples of technology that is instantly recognizable as “maritime related” & I love them greatly, as many have surmised upon spotting my wristwatch...

Excellent conversation starter, to say the least

/12

Range dials were great for getting a long string of info quickly transmitted from ship to ship, allowing concentrated fire, w/o fear of losing parts of the message.

They did, however, have the same drawbacks as other visual signaling: being obscured. /13

Other quick-reference markings for allied ships in battle included declination marks on turrets, which helped discern which direction they were aiming.

Combined, one ship could send range/bearing info to others whose own view was obscured by ships, spray, & smoke. /14

These were just two tools in a massive system of range finders across each ship, & that’s BEFORE we get to something like radar!

W/ radio & radar, range disks were phased out, removed during refits & rare on warships by WWII. /15

TLDR: these “clocks” are dials displaying distance, not time.

Further questions may be submitted via semaphore flag, as I assume you *don’t* have a range dial handy.

/16 -end