I was using the figures provided in an example posted by someone else.
Using *those* figures, I believe that my calc was correct.

Now, as for your figures, a big factor comes into consideration;
How does present day Earth tech-level scale up to TU level tech?
(others have mentioned that it won't necessarily be 'straight-line' analogous & I believe it's obvious were I stand on that)

As for a hypothetical world w/ a 1.1gigaTonne figure, let's see;
(BTW: Does 1 tonne = 1dTon? I don't think so but let's go ahead and postulate a world w/ 1.1giga dTons.)

Assuming an avg of 500dTon cargo cap amongst various size vessels they'd need about 2,000 thousand trips/year= 5.5 departures/day.
Not a very high figure at all but maybe too high for T5.
Naturally, an avg of 250dTon cargo cap amongst various vessels would yield about 11 departures/day.
*But* aren't these both imports & exports?  In that case ships can be counted twice as they can bring an avg of 500dTons, or 250dTons, & also take out the same amount.
But since they will also be arriving & departing they will count twice there too so it would be more accurate to say 5.5 (low-end) or 11 (high-end) arrivals/departures per day.
BTW, What's the ratio of im to ex?
I would assume it's not 1 to 1 so let's increase the number of arrivals & departures to about  8 (low-end) to 16 (high-end).

(Note that this assumes that ships might have to leave w/o a full load, which I've never seen taken into consideration.
The examples that I recall pretty much assume that ships will come in full & leave full.)

Still, very reasonable traffic levels.

------------------------------------------------------------------------------------
On Mon, 8/25/14, Tim <xxxxxx@little-possums.net> wrote:

 Subject: Re: [TML] expected ship traffic
 To: xxxxxx@simplelists.com
 Date: Monday, August 25, 2014, 5:00 PM

 On Mon, Aug 25, 2014 at
 07:37:58AM -0700, Phil Pugliese (via tml list) wrote:
 > I believe that 1000dT J2 merchantman could
 handle the trade from
 > Oz'.  About
 280-300 trips/year.

 By Oz
 you mean Australia?  According to Ports Australia, our sea
 trade
 for 2012-2013 was 1.1 billion
 tonnes.  So you're wrong by a factor of
 roughly a thousand.

 > And that's *If* such
 a trade could really be sustained in the TU,
 > which I doubt as, unlike the Earth the TU
 is not bound by an upper
 > TL limit of 8
 or 9. Which I believe changes things quite a bit.

 Given the canonical prices,
 wages, and TL disparities - no, if
 anything
 the TU should see more trade than MT ever envisaged.

 - Tim
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