How fast ocean waves travel in deep water, by the length of the wave

In deep water a wave 100 feet from crest to crest runs at 15 mph; a swell 1,600 feet long runs at 62 mph, a crest every 18 seconds.

What does this axis measure?

What does this axis measure?

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y ↑: Wave speed (mph)
x →: Wavelength (feet)

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The data: 40 points

Wavelength (feet)	Wave speed (mph)
50	10.9
100	15.4
150	18.9
200	21.8
250	24.4
300	26.7
350	28.9
400	30.9
450	32.7
500	34.5
550	36.2
600	37.8
650	39.3
700	40.8
750	42.3
800	43.6
850	45
900	46.3
950	47.6
1000	48.8
1050	50
1100	51.2
1150	52.3
1200	53.4
1250	54.5
1300	55.6
1350	56.7
1400	57.7
1450	58.8
1500	59.8
1550	60.7
1600	61.7
1650	62.7
1700	63.6
1750	64.5
1800	65.5
1850	66.4
1900	67.3
1950	68.1
2000	69

Source: Computed: wave speed = √(g × wavelength ÷ 2π) for waves in deep water (Wikipedia, Dispersion (water waves)), calculated by Unlabeled via Horace Lamb, Hydrodynamics, 6th edition (1932), section 228
Licence: Original computation by Unlabeled; nothing copied from the source
Read: 2026-11-03
Drawn: 40 points as the puzzle showed them · line

Ran in puzzle #40 on November 5, 2026. Play it