Ingermanland

Posted by cy on Wednesday 29th of June 2016 11:44

Yep, 3decks should be better than this. I was having a bad day, apologies. the measurement has been corrected to displacement

Posted by Robert Price on Wednesday 29th of June 2016 06:57

I'm sorry but Stephen is correct, there is no way this ship can physically be 1,992 ton burthen, that number is probably her displacement, one of the most common mistakes that even self-described experts make as they think the two are interchangeable, they are not. This is Osprey book level mistake, something 3decks should be above.
If we apply the older formula you mentioned (Length of keel x Beam x Depth in Hold) / 94, the Ingermanland gets about 1,214 tons burthen.

If we use length of keel she has even less. Measuring from inside or outside of planking would only change the tonnage by a couple of tons either way.

This is clearly a mistake in the source used.

The USS Constitution for example is 25ft longer and 2' wider of beam (the only 2 factors that go into any tons bm formula) than the Ingermanland and she is 1576 tons bm and 2,200 tons displacement. So, yeah.

Even more absurdly, the much, much larger HMS Victory is only 2,165 tons bm and 3,500 displacement. And you are determined for her to have nearly the same tonnage here as a 104 gun, 3 deck ship that is 40' longer, 10' wider and 11' deeper?

She simply is not 1,992 tons burthen by any math. Change it to displacement at least, in fact I'm sure that is what it is looking at other ships of her similar size in the sources.

The example of the Intrepid given by Stephen is accurate.

At least anyone coming to the page can see the clear evidence if you are determined to have her given the tonnage of a British 98 gun 2nd rate.

Posted by Cy on Tuesday 24th of May 2016 08:03

Actually the calculation for BM (in England at least) is (Length of keel x Beam x Depth in Hold) / 94, although at one time it used beam / 2. Later it became (length of keel for burthen), which was a calculated measurement and not the actual touch keel length. There is a 19C definition in the Glossary.
Note that different nations also used slightly different criteria for Beam (inside planking or over-all for example), at different times as well.
The burthen is as quoted from the source so I will not be 'correcting' it.

Posted by Stephen on Tuesday 24th of May 2016 02:25

She is not 1992 tons bm. "Builder's Old Measurement (BOM or bm) is the method used from approximately 1650 to 1849, the formula is (Length - (Beam x 3/5)) x Beam x (Beam/2) / 94"
So she is 1180 tons bm. For reference, the HMS Intrepid, 64 guns, is 159' 6" length, 44' 4" beam, she is 1374 bm. Please correct, thank you.