[tz] Maritime time zones

Tim Thornton tt at smartcomsoftware.com
Thu May 24 13:50:54 UTC 2012

Maritime time zones are well defined - basically every 15 degrees but with
the odd wiggle in them - see
They are identified by a letter, as shown in the above diagram.
They were created in the 1920s and I think are virtually unchanged since
Note that the nautical date line is different from the international date
Also, it uses GMT (i.e. UT1, not UTC) - I'm not sure if the tz database can
cope with this, or if the difference (< 1 second) is relevant for most tz
So they could be included in the TZ database if people feel this is good -
it would make the database more complete. Perhaps in a separate file, as
they are not associated with any of the continents?


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-----Original Message-----
From: tz-bounces at iana.org [mailto:tz-bounces at iana.org] On Behalf Of Steffen
Daode Nurpmeso
Sent: 24 May 2012 13:52
To: Sascha Wildner
Cc: tz at iana.org
Subject: Re: [tz] time zone abbreviations - uniqueness and meaning

"Sascha Wildner" <saw at online.de> wrote:

 |On Thu, 24 May 2012 12:11:32 +0200, Tobias Conradi
|<tobias.conradi at gmail.com> wrote:
 |> was: Re: [tz] Propose new zone for Crozet Islands  |  |How about just
working out all your little "proposals" privately and  |posting a _patch_ to
tzdata* like it is good practice?


 |I for one will subscribe to the announce list because I'm really getting
|tired of your seemingly endless, annoying dribble.

And i *don't* wanna do that, because there were really interesting topics
once in a while, and things good to learn about, and that's what it's about
for me.

And from what i know his last posts really revealed fuzzy stuff that could
be improved (or de-improved).  Here i'm with your first sentiment, though.

I in turn got response from the German Navy, the second.
Thanks to Herrn Kapitänleutnant Daub (Mr. Lieutenant Daub) and Herrn
Oberstabsbootsmann Jürgen Haak (Mr. Master Chief Petty Officer Juergen
For the German Navy:

  Wir können Ihnen hier lediglich Informationen darüber geben, wie
  die Schiffe/Boote der Marine es in der Praxis mit den Zeitzonen
  handhaben. So fahren diese in der Regel in den jeweiligen
  Zonenzeiten mit Erreichen des entsprechenden Gebiets.
  Sonderregelungen (z. B. während Manövern/Übungen) sind möglich
  und werden vorab bekanntgegeben.

So the germans basically agree with the post from the former Navy member
("normally local area time is used", "special arrangements are possible and
will be gazetted") if i recall correctly.
It was the "we have the better Kung-Fu" mail.  (And i was in doubt because
whoever has the better Kung-Fu actually didn't really understand what
Kung-Fu is about, but maybe it's simply a good job.  Sorry.)

  Möglicherweise kann Ihnen aber das Bundesamt für Seeschifffahrt
  und Hydrographie bezüglich der rechtlichen Regelungen Auskunft
  geben bzw.  zuständige Ansprechpartner benennen.

Yes, i didn't have had a clue and should of course have asked the Federal
Agency instead!
The question is - should i really do that?  Does it *really* matter what
timezone a ship uses regarding to the timezone database?  Maybe i have
mislead myself.  On the other hand i'll send another mail if some
international law actually exists (which is what i have asked for), for

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