Junon Class

Posted by F.F. on Friday 18th of November 2022 19:05

«700 tonneaux» was the «port» of these frigates. Port has, etymologically, exactly the same meaning in French than burden / burthen has in English, yet what is called «port» for a French ship was her deadweight tonnage, the French translation for burthen being «jauge».

Burthen was hardly ever used in France (or in Spain) except for merchant ships. For a one-decker, the formula, from 1795, was: gun-deck × beam × depth to deck ÷ 94 (here: 142 × 36 × 18¾ ÷ 94 → 1020 «tonneaux de jauge»). Most often was given, for war ships, their deadweight tonnage, and sometimes their displacement, the former being more or less one half of the latter in larger war ships. One «tonneau de poids» was equal to 2,000 French pounds, or some 2158.37 pounds. Here, 700 «tonneaux de port» are equal to some 675 long tons, the displacement being likely some 1300 long tons.

A French admiral refered to a frigate in 1803, also mounting eighteen pounders, which displacement was 1396 «tonneaux de poids» (≈ 1345 long tons), her «port» being some 800 «tonneaux de poids».