Technology can be described as the use of increased engineering complexity to improve efficiency as determined by cost verses benefit.
If we look at technology in the way I have described.
Is the technology of modern diesel ships less than say the tea clippers at the height of the age of sail.
From the current economic viewpoint it can be argued that it is.
Basically we have gone from ships with a net fuel cost of zero to ships that run on oil based fuel whose price is increasing year on year.
More to the point consider where sail based technology would be today if we had continued along the line of producing increasingly advanced sailing ships.
It is not too late to develop this sail technology and it is already being done.
Today we have the possibility of hybrid sail/solar/diesel powered ships (we still need the diesel engines when there is no fuel).
Of course the design of large oil tankers and cargo vessels will have to be re-thought employing a much wider shallower design to reduce water friction on the hull either employing a large deep keel or a twin hull design to compensate for the tall masts.
This would also require a redesign of harbors.
The goal of having a merchant fleet which consumes maybe a 5th of the fuel of today's fleet is well worth the effort.
Imagine the reduction in the use of precious oil reserves and imagine the impact on reducing CO2 emissions.
In my opinion there should be an international agreement requiring that all ships be sail/solar/fuel hybrids by the year 2020.
All we need to do is put pressure on industry and world governments to make this happen.
Best regards, Simon