Why do we say "Shipshape and Bristol fashion"?

Quoting from an archived copy of a page on RNJobs.co.uk (The Royal Navy - Jobs):
"This expression may well have had its origin in the XVIII century when Bristol was the second most important commercial port in the United Kingdom. In those days (Bristol's docks were not constructed till 1804), the high range of tides experienced at Bristol necessitated ships berthed alongside there being left high and dry at the fall of the tide and so ships regularly trading to Bristol had to be of specially stout construction."
Link: https://web.archive.org/web/20050414174853/http://www.rnjobs.co.uk/static/pages/4761.html

Second attempt, this one quoted from Daniel Reisel's Web site "Broca's Area":
"Shipshape (in neat order) is a tribute to the traditional high standards of good order on board sailing ships, especially in the Royal Navy. The second syllable is a shortening of 'shapen', the old form of 'shaped', i.e. fashioned. Shipshape and Bristol fashion means the same: before the growth of Liverpool, Bristol was the major British west-coast trading-port with a high reputation for the standards of equipment and service needed for long voyages."
Note: "Brewer's Dictionary of Phrase and Fable" also agrees with this explanation.
Link: http://www.broca.org/2002_09_01_archive.html

I saw this on't Telly las' nite!

Because Bristol has the highest raise and drop of water in the country, all of the things inside the ship had to be locked in cupboards and tied down so it did not break or fly out when the waters went down so rapidly. When the waters did go down, the boats would often fall over on their keels. So everything inside had to be neatly stowed away, all 'ship shape and Bristol fashion'.