Portuguese measurements

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sgtfox
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Location: Idyllwild, California

Portuguese measurements

Post by sgtfox » Sat Jun 17, 2017 5:31 pm

French Warships in the Age of Sail 1786-1862 by Rif Winfield and Stephen Roberts lists several Portuguese warships captured by the French in 1807. They contain the French measurements of said vessels. When you multiply the French feet by 1.066, they pretty much match the Portuguese feet measures in Tres Seculos No Mar. Of course there are some typos in the later, and the French don't always seem to measure the same way, but it more or less proves to me that Portuguese feet, for ship measurement, was based on the Imperial system. That said, you must look up French ships of a similar class to the Portuguese ship to be converted, then go to Rif's French book to see the original measurements. Comparing the Imperial versions will give you the method the British used for measuring. In most cases, the British would have a shorter length, but a slightly wider width, due to their way of measuring tonnage. Once you have the adjustments in mind, you can adjust the Portuguese measurements accordingly. I like to figure the British method of keel length and apply it to the Portuguese ship to be measured. That makes getting the tonnage easier and more accurate. The formula would simply be keel length times 1 1/2 the width divided by 94.
When I designed my wargame rules, Beat to Quarters, in 1980, there was no internet, and I was unaware of the "new" set of books out on the Portuguese Navy. I wanted to include the Portuguese in the game, so I used some information from another designer. Turns out he was guessing, so I was off the mark. There is no need to pull numbers out of the air for Portuguese tonnages in this day and age. Common sense and the books mentioned will get you closer to the mark. That said, the obvious typos, often repeated in Tres Seculos can leave one hanging. Case in point, all 64 gun ships are listed as 182 x 44 Portuguese feet. The length is totally off when compared with similar ships of other navies. It appears that 162 feet would be more correct. That said, the French measured a Portuguese 64 in Lisbon and got very close to 182 x 44 in Imperial measure. Were the French just being lazy, since they had a record of the Portuguese measurements? Perhaps there are other reference works out there other than the many I now possess, and I would be happy to hear about them.

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