1 · Historical weight: why “a ton” and 2,700 lb can both matter
MacLeod’s 1893 Gaelic account calls the object a ship’s anchor “weighing a ton,” says MacAskill put it on his shoulder, and says he was injured while lowering it. [1] Gillis’s 1899 account gives 2,700 lb in one version. [2] Arthur Young’s 1863 merchant-vessel table gives 18.5–20.5 cwt of anchor for a 400-ton vessel. [3]
20 cwt × 112 lb/cwt = 2,240 lb = 1 long ton
2 · Stock mass: how ~2,240 lb can approach ~2,700 lb
The 1794 Royal Navy plan gives a 20-cwt anchor a 13-ft shank and an arm about 4 ft 4.5 in long. [4] Steel (1794) says the stock was two oak beams mounted transverse to the flukes; stock length was about the shank length plus half the ring diameter, with the middle section sized in inches roughly equal to stock length in feet and the ends half that size. [5] Working approximation: L = 13.5 ft, center side D = 13.5 in = 1.125 ft, end side E = 6.75 in = 0.5625 ft.
V ≈ L(D² + DE + E²)/3 = 9.97 ft³
USDA material gives dry oak at about 44 lb/ft³. [6]
9.97 × 44 ≈ 439 lb of wood
2,240 + 439 = 2,679 lb ≈ 2,700 lb
Interpretation: the 1893 “ton” could plausibly reflect nominal iron-anchor weight, while 2,700 lb could approximate the complete stocked object. This is a hypothesis, not something either source explicitly explains.
3 · Why one fluke is ~2 ft above the wharf
Use the measured arm A = 4.375 ft and Steel’s ~60° arm geometry. [4][5]
a = A cos60° = 2.19 ft r = A sin60° = 3.79 ft
Let the crown be C = (0, 0, 0), the lower fluke L = (2.19, 3.79, 0), and one stock end S = (13, 0, 6.75). Those three contact points define a plausible stable ground plane. The opposite fluke is U = (2.19, −3.79, 0).
h = |(L × S) · U| / ‖L × S‖ = 1.95 ft ≈ 2 ft
This is a model of one plausible three-point resting orientation (crown + one fluke + one stock end), not a measurement of MacAskill’s actual anchor.
4 · Initial rotational force: why the estimate is ~870 lb
A simplified component model places the 2,240-lb iron body’s center of mass near 4.0 ft from the crown (central estimate; modeled range ~3.5–4.2 ft); adding a ~439-lb stock centered near the upper shank moves the assembled center of mass to:
xG ≈ (2240×4.0 + 439×13) / 2679 = 5.47 ft
About the tipping edge from the lower fluke to the grounded stock end, the 3-D model gives a ~7.00-ft moment arm at the raised fluke and ~2.27 ft at the center of mass.
F × 7.00 = 2,679 × 2.27 → F ≈ 868 lb ≈ 870 lb
The wharf is still supporting the anchor. The 870-lb figure is the estimated upward force needed to start rotation, not a claim that MacAskill freely supported 2,700 lb.
5 · Modern tire-flip benchmark
Guinness lists the heaviest tire flip at 628 kg / 1,384.5 lb. [7] In an ideal rigid-tire model, the center of mass is one radius from the pivot and the lifting edge is two radii away:
Ftire ≈ W/2 = 1,384.5/2 = 692 lb
870 / 692 − 1 ≈ 0.26 → ~26% higher theoretical starting-force scale
This is a scale comparison, not a laboratory measurement: tire deformation, grip, acceleration, and anchor contact geometry differ.
What is sourced vs. modeled
Historical sources support the story, the one-ton/2,700-lb descriptions, period anchor sizes, anchor geometry, stock construction, and the tire record. The ~439-lb stock, ~2-ft fluke height, center of mass, and ~870-lb force are explicit reconstructions from those sourced dimensions.
Sources
- Donald MacLeod, “Mac Asguill Mor,” Mac-Talla, Vol. II, No. 5, p. 5 (29 July 1893). Original page scan · DASG searchable volume
- James D. Gillis, The Cape Breton Giant: A Truthful Memoir (1899), Ch. XXIV, “He Shoulders a Monster Weight”; CIHM 05930. Canadiana scan
- Arthur Young, Nautical Dictionary, 2nd ed. (1863), “Anchor” table: 400-ton merchant vessel → 18.5–20.5 cwt. 1863 text
- Royal Museums Greenwich, ZAZ7913, “Anchor weights and measurements in the Royal Navy (1794)”; dimensions taken from actual measurements. RMG record
- David Steel, The Elements and Practice of Rigging and Seamanship (1794), anchor-making section: ~60° arm geometry; two-beam oak stock; stock transverse to flukes; stock proportion rules. 1794 text
- USDA Forest Products Laboratory, B. H. River et al., “Wood as an Adherend” (1991): dry oak ~44 lb/ft³. USDA PDF
- Guinness World Records, “Heaviest tyre flip (male)”: 628 kg / 1,384.50 lb, Xiao Yang, 9 Nov. 2025. Guinness
- Context: South Street Seaport Museum documents a ca. 1850 Admiralty anchor from New York’s East River weighing 5,000 lb. Museum page
- Context: Smithsonian National Museum of American History notes New Orleans was the second-busiest U.S. port by 1850. Smithsonian