Lesson previewSeasickness: Protect Crew Capacity1 section shown
Preview lesson
Seasickness: Protect Crew Capacity
What you will learn
Recognise early motion-sickness evidence, protect the person and remove unsafe duties before vomiting, dehydration or exhaustion erodes the boat's safety margin.
Seasickness is common, but the safety decision is about observed function: protect the person, preserve crew capacity and keep another illness or injury from hiding behind a familiar label.
NHS motion-sickness guidance lists dizziness, nausea, vomiting, headache, feeling cold, pallor and sweating. A moving boat can explain that pattern, but it does not prove the diagnosis. Head injury, low blood sugar, heat or cold illness, infection, medicine effects and anaphylaxis can also change response, balance or behaviour, so keep the observed evidence visible.
Move the person away from immediate deck and overboard hazards, give them a stable supported place, fresh air and a view of the horizon where conditions allow, and use a lifejacket, tether or direct supervision appropriate to the actual deck risk. Relieve them from helm, navigation, lookout, radio or machinery work as soon as nausea, dizziness, poor concentration or medication makes that role unreliable.
Reassess the passage as well as the casualty. Remaining crew, weather, distance to shelter, access to help, repeated vomiting and the person's trend decide whether to continue, turn back, divert or call. The sunk cost of the plan is not evidence that the safety margin remains adequate.
Sickness and medicine board
Protect function, preserve evidence, escalate change
Select an observed situation to compare role safety, evidence, oral and medicine boundaries, passage planning, escalation and handover. Every state is complete in text and does not depend on colour.
- 1Protect + role
- 2Observe
- 3Oral / medicine boundary
- 4Passage plan
- 5Call + update
- 6Handover
These stages can run together. A medicine record cannot delay airway or breathing care, and a familiar seasickness pattern cannot explain away deterioration.
1 · Protect + role
Move the person away from immediate deck hazards, support them in a safer lower-motion place and name another person for any helm, lookout, navigation, radio or machinery duty that is becoming unreliable.
2 · Observe
Record nausea, pallor, sweating, dizziness, headache, response, balance, vomiting, intake and change. Keep impact, low blood sugar, heat, cold, infection and medicine effects in view rather than diagnosing from one familiar pattern.
3 · Oral / medicine boundary
Use fresh air, a horizon reference and slow breathing where safe. Any medicine remains the person's own product used to its exact label, leaflet and professional advice; do not share or invent a dose.
4 · Passage plan
Compare remaining competent crew, sea state, workload, distance to shelter and the trend before committing farther offshore.
5 · Call + update
Seek professional advice early when symptoms persist, the cause is uncertain, oral intake is failing or the boat's safety margin is shrinking.
6 · Handover
Give onset, observed symptoms, duties stopped, vomiting, intake, medicines, allergies, relevant history, vessel position and change.
Choose an observed situation and rehearse role safety, evidence, oral or medicine boundaries, passage planning, escalation and handover without diagnosing or prescribing.
Worked example
Forty minutes after leaving harbour, the navigator becomes pale and sweaty, stops checking the chart and says the compass card will not stay still.
- 1The skipper transfers navigation to the named backup and moves the person to a supported, lower-motion position with fresh air and a horizon view where safe.
- 2A buddy records response, vomiting, fluid intake, medicines and change while checking that no impact, low-blood-sugar plan or other cause is being missed.
- 3The skipper compares remaining crew, sea state, distance to shelter and the person's trend before committing farther offshore.
Sense check: The intervention protects both the person and the navigation function; waiting for vomiting would spend crew capacity without adding useful evidence.
| Observed evidence | Immediate protection | Unsafe inference |
|---|---|---|
| Nausea, pallor, sweating or dizziness | Safer position, fresh air, horizon reference and buddy observation | They can keep a critical role until they actually vomit |
| Poor concentration or coordination | Relieve the duty and assign named cover | Qualifications cancel current impairment |
| Vomiting or declining intake | Start a fluid-loss record and reassess the passage | One familiar label explains every later change |
| Confusion, abnormal breathing or collapse | Call now and use the current first-aid response | Wait for more typical motion-sickness symptoms |
Protect the person and the role together
A two-person crew has one seasick helm and the other person is reefing on deck.
1. Stabilise the boat task
Reduce avoidable workload and establish who can safely control the vessel now.
2. Protect the person
Use a supported safe position, supervision and the practical motion-sickness measures that do not add deck risk.
3. Change the plan early
Choose the safest manageable route before the remaining crew is also overloaded.
Sense check: A passage decision can be correct before the person meets any medical emergency threshold.
Common mistake or limitation
- Mocking or minimising symptoms until the person is unable to help.
- Leaving a dizzy or drowsy person on helm, lookout, navigation or machinery duty.
- Calling every later change seasickness without checking the observed ABC and history.
Recap
- Recognise the symptom pattern but avoid a browser diagnosis.
- Protect the person, reassign unsafe duties and preserve crew capacity early.
- Let the casualty trend and the remaining passage margin drive the next plan.
Optional quick check
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