Re: Evolution and stuff (was: Re: HTML: woes)

Michael Lorrey (
Tue, 17 Mar 1998 19:17:30 -0500

Erik Moeller wrote:

> >Still, Erik's previous claim, that the biggest medieval ship (about 200
> >tons, was it?) would not be allowed in a Roman harbor, is invalidated.
> The biggest Scandinavian ship was, according to "Aspects of Maritime
> Scandinavia" (1991) 155 tons in cargo size. The biggest Venecian ships, of
> the 14th to 15th century (end of MA, beginning Renaissance) was 200 to 300
> tons in cargo size [1].
> My memory was a bit wrong, the biggest ships that were allowed to enter the
> harbour were 134 tons in size (not 150 as I stated). See my post on this:
> Subject: Re: Evolution and stuff (was: Re: HTML: woes)
> Date: Mon, 16 Mar 1998 19:03:39 +0100
> Cargo ships of more than 1200 net tonnage (the size of the Roman ISIS, of
> which type at least 60 to 80 ships existed, because of the high wheat
> requirements of the empire, however, it was probably much more) were only
> built again in 1800 (!) in larger series [2].
> Nelson's "Victory" had 3000 brutto register tons, the ISIS had 2900 BRT.
> Conclusion: The biggest Scandinavian ships would barely have been allowed to
> enter the Roman harbour, and the *biggest* late MA / early Renaissance
> Venecian ships were still under the *average* Roman size.

And how does one parameter, the gross tonnage of the average vessel, apply to
naval technology? Not at all. For example: in WWII, the largest Japanese vessels
were the Yamato Class battleships, at around 75,000 tons, and a little known
large aircraft carrier program that was never finished that had a vessel size of
100,000 tons. THe most advanced US vessels were the Essex class carriers
(~50,000 tons) and the Missouri class battleships (~65,000 tons). The Japanese
carrier was to carry over 150 aircraft, while the US Essex was to carry less
than 100. The Yamato battleship had 18 inch main guns, while the USS Missouri
had only 16 inch main guns, as well as half the total number of guns as the
Yamato. Yet the US vessels were technologically several years advanced ahead of
the Japanese vessels. They had radar and gun ballistics computers, for starters.

As for Roman vessels, the Isis class vessel, was, as I recall, mostly a
glorified self propelled grain barge. Hardly a feat of naval engineering, and
more a matter of economics than engineering. Its not surprising that such
vessels were not needed during the middle ages, as population was less, trade
was less, and what was left of Rome couldn't afford fine Libyan wheat (which was
the point of the Isis, to ship wheat from North Africa to feed Rome (the 'bread'
part of the 'bread and circuses')). I also would doubt highly that the Isis
could do more than 6-8 knots or survive more than 6-8 foot seas. The smaller
middle ages vessels were more seaworthy, built for the North Atlantic, not the
calm Mediterranean.

   Michael Lorrey
------------------------------------------------------------ Inventor of the Lorrey Drive
MikeySoft: Graphic Design/Animation/Publishing/Engineering
How many fnords did you see before breakfast today?