The clipper ship era / an epitome of famous American and British clipper ships, their owners, builders, commanders, and crews, 1843-1869

by Arthur H. Clark

The old practice of calculating tonnage in the United States was adapted from the English, and the mode of measurement was as follows:

The length was measured on deck from the fore part of the stem to the after part of the stern-post; the breadth from outside to outside planking at the broadest part of the vessel; the depth of the hold from the plank on deck to the ceiling of the hold. This last measurement was not used, the depth of a vessel for tonnage purposes being assumed to be one half of her breadth. In order to find the tonnage, three fifths of the breadth were deducted from the length and the remainder multiplied by the breadth, and this product multiplied by one half the breadth, or the assumed depth, the last product was then divided by 95, giving the formula:

(L - ⅗ B) × B × ½ B

95

Thus in a vessel measuring 100 ft. x 20 ft. x 18 ft.:

Length of vessel	100
Subtract â…— breadth	12
Length for measurement	88
Multiply by the breadth	20
	1760
Multiply by half breadth	10
	17,600

Divide 17,600 by 95	and
the result is	185 + 12/19
Total tonnage	185 + 12/19

This mode of measurement continued from colonial times until the Moorsom system was adopted in 1865.

The dimensions of ten representative American and British clippers were as follows:

		Length			Breadth
	Nightingale (1851)	178	“		36	“
American	Oriental (1849)	183	ft.		36	ft.
	Celestial (1850)	158	“		34	“	6 in.
	Stag-Hound (1850)	209	“		39	“
	Flying Dutchman (1852)	187	“		38	“	6 in.
British	Falcon (1859)	191	“	4 in.	32	“	2 in.
	Taitsing (1865)	192	“		31	“	5 in.
	Titania (1866)	200	“		35	“
	Spindrift (1867)	219	“	4 in.	35	“	6 in.
	Thermopylæ (1868)	210	“		36	“