Tac Numbers

[from the stabenow.com vaults, 2007]

April 19

They’re on every bulkhead in every compartment of this ship, they’re on doorways and light fixtures and valves. When we have a fire drill the affected space is identified by tac number and BM3 Tim Stamm finds it and marks it on the white lucite map of the ship on the bridge. (see photo) It’s standard nomenclature for ship’s spaces, equipment, the engines, the turbines, everything. If I look at the bottom of a ketchup bottle, I will very probably find a tac number.

ship's map

I’m embarrassed to admit that even after the XO’s painstaking explanation of tac numbers I was still horribly, well, at sea. I’ve spent time in front of that bridge map, trying to wrap my head around the system, and I still didn’t get it. The numbers just seemed so arbitrary, they didn’t make sense. For five weeks now, it didn’t matter where I turned (it starts when I wake up in the morning, see photo), I was being hammered with my own instransigent ignorance.

movie call

Then last night I was at movie call, and allow me to digress a little here. Chief Marc Blecman had some bed sheets sewn together and hung them up on the hangar door (“Next time we should just buy a screen,” he says), ET3 Javed Mohammed set up a DVD player and speakers and the crew brought out deck chairs and popcorn and watched a movie under the stars. The movie was “Made in Prison,” but nevertheless another good idea to relieve underway tedium.

I lost orbit and wandered off after the movie, allegedly a comedy, gave me the annual statistics about rapes in American prisons. On the fantail I bumped into MPA Andy Molnar and Chief Dale Brown. Earlier that evening the shellbacks on board had sent the pollywogs on three different tac hunts to sign up for the crossing of the line ceremony. I, naturally, had failed utterly at all three. Dale decided to take me in hand and explained the tac number system yet again, speaking slowly and carefully, as if to a very small, idiot child. He is a perspicacious man.

He explained a second time. A third. My forehead remained wrinkled and he was losing patience. I didn’t blame him. “What exactly is a frame, anyway?” I said. He hauled me up the portside deck past the trash pile and pointed. A giant light bulb went on over my head. “It’s a rib!”

frames, aka ribs

Why didn’t somebody say so? I get ribs. (see photo, they’re the long, vertical rectangles running parallel against the bulkhead) Shipwrights lay a keel or backbone of a ship, bow to stern, perpendicular to which they lay the frames, or ribs, which form the U-shape of the hull. The ribs are numbered, just like doctors name the ones in your chest, beginning with 1 (or they do aft of the forward perpendicular, which according to LTJG Josh Dipietro is a whole ‘nother dissertation and I’m not going there) and on this ship occuring at one-foot intervals all the way to the stern.

After that, it’s easy. There is an imaginary centerline running fore to aft, named zero, like the equator. Everything portside of the equator is even numbered, everything starboard is odd numbered. MDE 1 (main diesel engine 1) is starboard, MGT 2 (main gas turbine 2) is port.

ENS Greg Vera with hangar bullseye

Decks above the main deck (1) begin with zero, so up one from the main deck (1) the hangar deck/boat deck/flight deck is 01. See photo of ENS Greg Vera pointing at the bull’s-eye on the hangar. Bull’s-eyes are the big signs in each space. “There should be one in every space,” Greg says. “The larger the space, the more entrances it has. The rule is the bull’s-eye has to be visible from any entrance, so the larger spaces have multiple bull’s-eyes.”

the Vise Gang's address

Decks below the main deck are whole numbers. So the Vise Gang’s address is 2-304-2-Q. 2 is one deck down from 1, the main deck. 304 is the frame number, so if zero begins more or less at the bow and the ship is 378 feet or frames or ribs long, this is well aft. 2 is even-numbered, so they’re on the port side of the centerline or the equator of the ship. Q means miscellaneous, like for the repair shops.

my address

My address is 1-111-1-L (1 tac 111 tac 1 tac L, is where the tac comes in).
1, I’m on the main deck.
111 is the frame (rib!) number of the compartment, so more or less 111 feet aft of the bow, or at least aft of the forward perpendicular.
Third number, 1, indicates which side of the ship (or which side of 0, or the equator), so I’m on the starboard side (odd number).
L says it’s a living space. W is for water, F is for fuel, E for engineering, A for armory, and C for control (main control, the bridge and CIC).

my stateroom

By George, I think she’s got it. I feel so powerful.

Like I said, there are tac numbers on every fixed object everywhere on the ship. If you master this system, you will never be lost. Good luck!

Click here to order a copy.


Dana View All →

Author and founder of Storyknife.org.

12 Comments Leave a comment

  1. Ok Dana

    We know the the Vise Gang is a kick a$$ group from an earlier post, and now know where they live.

    But who and what is the vise gang?

    BTW – Big Thank you on today’s post – I never understood the numbering system either. You gave a great explaination!

    a clueless vise gang parent 🙂

  2. The Vise Gang hangs out in Repair Locker 3. They are part of the Auxiliary Division in Engineering, and their motto could be something like “We Do Everything Else.” Anything that needs fixing that isn’t about the engines and the turbines, they do it. MK3 (may have got that job title wrong, if so I’ll find out and fix it later) Shawn Milton has fixed the faucets in my sink, re-fastened the handrail to the stairs outside my door, and he’s a student in my underway writer’s workshop and just wrote me a paper about unplugging the sewage tanks that had me laughing out loud.

    You’d have to ask them, but I’m guessing it’s one of the better jobs on board, because engineers are curious types and this job let’s them go everywhere and puzzle out ways to do everything. It’s especially challenging because we’re underway, and they have to make things work with what we have on hand. They are true sons of Martha, like the Kipling poem says.

    What I said. Kick-ass.

  3. I knew you were a woman of my own heart, Dana. Who else would use perspicacious in a blog? I really enjoy reading it, especially because you’re way more forthcoming than my husband is about what goes on. Thanks, Syntha

  4. Addendum: A Farscape reference too, be still my beating heart. I could almost wish I was on the boat to enjoy your company instead of my husband (sigh).

  5. Petty Officer Milton is a DC2 and actually is aboard temporarily helping us out. The DC’s, besides being our experts in damage control (fire, flooding, locusts – that sort of thing), maintain our sewage system and are typically expert welders and have an air of excellence for loving a challenge. One of their earlier ones from this patrol was figuring out designs and building brackets so a white erase board could be hung on the mess deck for use during algebra classes.
    Oh, by the way, thanks. I understand the numbering system much better.
    As to ‘perspicacious’ – we’re just a bunch of simple sailors not writers. If you won’t try to drive the ship, I won’t try to write blog entries! Deal?

    The Captain

  6. Dana, Thanks for the explanation about the tac. I didn’t know that everthing fixed on a ship had a number. It was very interesting and fun to hear how you finally figured it out!

    Syntha, I guess now you know why there are so many of us DANAMANIACS and how fitting the name is!

Leave a Reply to DanaCancel reply

%d bloggers like this: