# @stem_antics on Instagram

- **Type:** Video
- **Original URL:** https://www.instagram.com/p/DbTTXPugmgq
- **Gondola URL:** https://gondola.cc/posts/68532559-stem-antics-instagram
- **Thumbnail:** https://img.gondola.cc/tr:w-,h-,fo-auto/postThumbnails/66f9880c12.jpg
- **Posted:** 2026-07-27T15:38:47.000+00:00
- **Account Owner:** Stem Antics (@stem_antics) — https://gondola.cc/stem_antics

## Caption

Solo ocean racers do not sleep. They ration it.

Twenty minutes at a time, sometimes less, spread across the whole twenty-four hour clock. The physiology behind this was mapped by a chronobiologist rather than a sailor.

Human sleep runs in ultradian cycles of roughly ninety minutes, descending through light stages into slow-wave sleep before surfacing towards REM. Waking out of slow-wave sleep produces sleep inertia: a window of degraded reaction time and poor judgement that can last half an hour. A nap capped near twenty minutes usually ends before deep sleep consolidates. The sailor wakes functional.

Claudio Stampi studied competitors through the BOC Challenge and the solo races that followed. His finding held. Racers who fragmented sleep into many short naps outperformed those taking fewer long ones on identical total hours. Daily totals often fell to four or five hours for weeks at a stretch.

Nap length is set by geometry as much as by neurology.

- A container ship makes twenty knots. A racing yacht makes eight.
- Meeting head on, closing speed is twenty-eight knots.
- Twenty minutes of sleep therefore covers roughly nine nautical miles of closure.
- Detection ranges must exceed that margin, with time left to act.

The layered defence:

- AIS alarms keyed to closest point of approach and time to closest point of approach
- Radar guard zones that sound on any target entering a set annulus
- Autopilot or windvane holding course through the nap
- Mechanical timers, because a flat phone battery is a hazard rather than an inconvenience

Sailors sleep dressed and harnessed, in the saloon rather than a forward bunk. Time from waking to deck matters more than comfort does.

COLREGS Rule 5 demands a proper lookout at all times. Singlehanded ocean sailing lives in permanent tension with that sentence.

Fatigue at sea is not endured. It is engineered.

#stemantics #sailing #chronobiology #sleepscience #marineengineering

## Stats

- **Views:** 36,059
- **Likes:** 1,744
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- **Comments:** 15

## Tags

sailing, marineengineering, chronobiology, sleepscience, stemantics

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