Recently I have commented on the 4100teu container ships introduced to the New Zealand trade in 2002, and the departure from it, of eight of them, in the last three years.
This round-the-world service officially commenced in November 2002, and the 10 ships built for it were required to maintain a very taxing 70-day round voyage schedule.
But as time went by, port delays and other contributing factors resulted firstly in Fremantle being dropped from the schedules and later two Amercan east coast ports.
Even with these measures, the ships often ran very late.
Despite their short-lived tenure in the New Zealand trades, these third-generation vessels remain the largest cargo vessels to have been built for it.
All had provision to carry 1300 refrigerated containers, but homeward-bound with export cargo they only carried about 2500-2600 boxes, nowhere near their stated 4100teu nominal capacity.
To date, the largest container ship to visit Port Chalmers, last December, was the 294m-long, 54,771gt, 5018teu, Offen-owned Maersk Detroit.
Port Otago currently has plans for port development in readiness for even larger vessels that will eventually enter the New Zealand trade.
There have been many changes since container ships first started calling here 39 years ago.
While the names of a number of operators have been swallowed up by mergers or restructuring, there were others that came and went, or went out of business.
As for the earlier visitors, many gave years of sterling service.
The local trade was inaugurated when the 1187teu Columbus New Zealand berthed on its maiden voyage on June 26, 1971.
Later that year, it was joined by sister ships Columbus Australia and Columbus America.
Built for the North American east coast/Australia/New Zealand service, they remained on that run until sold for demolition in 1998-99.
The first-generation British-owned vessels were units of the ACT and OCL fleets built from 1969-72 for the Australian trade.
Transferred later to the New Zealand trade, most of them went to the breakers over the period 1998-2003.
And four of the five larger second-generation, 2300-2400teu, /ACT 7/Resolution Bay-type vessels built in 1977-78 went for scrap in 2002 when the 4100s came on stream.
When OCL introduced the 1530teu Encounter Bay class in 1969, they were the largest container ships in the world.
And when the 4100s were introduced to this trade eight years ago, they were described as "super ships".
But how things have changed, for by today's standards they would fit more comfortably into a modest medium-size range.
Over the last few years it has been onwards and upwards to even larger mega-ships in excess of 10,000teu.
In 2008, Mediterranean Shipping introduced its 151,559gt, 366m-long MSC Daniela with a declared 14,000teu capacity.
Earlier this year, the first of 12 similar capacity vessels ordered by Claus-Peter Offen entered service on charter as the 153,115gt, 366m long MSC Savona.
Both classes were ordered from South Korean yards.
Four years ago, Maersk took delivery of the 170,794gt, 397m-long Emma Maersk, the first of eight sister ships order-ed from its own Odense shipyard.
The company was always very vague about their capacities and gave the impression that they were about 11,000teu.
But now they have declared that their capacity is 14,770teu.
