Module 20 - Special Situations Afloat
Advanced Scenario Check: Grounding, Flooding and Injured Crew
What you will learn
Control a compound night casualty by measuring ingress, protecting steerage and casualty care, and escalating before the remaining sea room and power are consumed.
A compound casualty defeats single-topic recall. The advanced task is to run several workstreams without allowing a technically attractive action—such as restarting the engine—to create the next failure.
At 2310 a fictional yacht touches a charted shoal and the helm becomes heavy. One crew member falls and sustains a head injury. Bilge depth at a marked point rises from 12 cm to 18 cm by 2316. The engine is stopped; deeper water lies astern and the tide is rising. VHF contact is available.
The first six-minute observation gives (18 − 12) ÷ 6 = 1.0 cm per minute at the mark. At 2316 the main pump starts. By 2320 the level is 20 cm: a net rise of (20 − 18) ÷ 4 = 0.5 cm per minute with the pump running. The pump is helping but ingress remains uncontrolled. Bilge geometry is not known, so no litres-per-minute claim is justified.
Do not restart and motor astern merely because deeper water is available. Steering is degraded, underwater damage is unknown and the grounded hull may be supporting the breach. The rising tide changes water depth but does not prove that movement is safer. Keep the yacht controlled, investigate only with safe access and preserve the propeller, rudder, batteries and communications.
Run parallel roles: trained first aid and casualty observations; helm/lookout and position; flooding containment and timed level; VHF/Coastguard update; survival preparation. Report the grounding, injury, control state, timed water trend, pump state, position, tide and intended fallback. Escalation must reflect the combined danger rather than waiting for one subsystem to fail completely.
The next safe state may be remaining supported for assisted recovery, a controlled move after hull/steering evidence, or abandonment if the yacht becomes less safe than the raft. This scenario does not prescribe a universal MAYDAY word, astern setting, tow or abandonment time. It requires the skipper to state which observed change creates grave and imminent danger, which options remain and why the chosen transition is safer.
Worked example
Audit the timed water evidence and give the first defensible command update at 2320.
- 12310–2316: depth rises 6 cm in 6 minutes = 1.0 cm/min at the marked point.
- 22316–2320 with pump on: depth rises 2 cm in 4 minutes = 0.5 cm/min net.
- 3State 'pump reduces the observed rise, but level is still increasing'; do not call it controlled.
- 4Keep engine use withheld while breach, propeller, rudder and the consequence of moving into deeper water remain unknown.
- 5Assign casualty care, vessel control, containment/measurement and Coastguard communication as separate owned roles.
- 6Prepare survival equipment and state the water-level, stability, power, control or casualty trigger that moves the response to immediate rescue or abandonment.
Sense check: The water trend improved by half but did not reverse. A quieter alarm or a running pump cannot turn +0.5 cm/min into a stable level.
| 2320 evidence | Meaning | Command consequence |
|---|---|---|
| Bilge +0.5 cm/min with pump | Ingress not controlled | Contain, measure, escalate and protect power |
| Heavy helm after grounding | Steering/underwater damage uncertain | Withhold casual engine manoeuvre |
| Head injury with changing state | Medical trajectory may worsen | First aid, record and Coastguard advice |
| Rising tide and deeper water astern | More float depth and possibly greater flood consequence | Compare support with movement; no automatic refloat |
| VHF still available | Coordination option exists now | Use it before power or coverage is lost |
Give the 2320 read-back
A crew member says, 'The pump has it now; restart and get us off before the tide rises further.'
1. Correct the fact
Water is still rising at the mark with the pump running, so ingress is not controlled.
2. Protect against cascade
Do not add propeller, rudder or deeper-water exposure while underwater damage remains unknown.
3. Coordinate help
Update Coastguard with position, casualty state, steering, grounding and timed water trend.
4. Name the transition
State what evidence releases controlled movement and what worsening trigger demands immediate rescue or leaving.
Sense check: The fastest visible action is not necessarily the fastest route to a safer state.
Common mistake or limitation
- Calling the bilge controlled because the pump halved the observed rise.
- Converting depth change to a volume flow without knowing the bilge geometry.
- Treating rising tide and deeper water as automatic permission to motor astern.
- Letting casualty care, flooding response or communications consume every competent person and leave the yacht uncontrolled.
- Waiting for total loss of buoyancy, power or consciousness before escalating the combined casualty.
Recap
- The checked water trends are +1.0 cm/min before pumping and +0.5 cm/min with the pump on.
- Still rising means ingress is not controlled; depth alone does not reveal litres per minute.
- Grounding, steering uncertainty, flooding and injury must be managed as parallel workstreams.
- Preserve communications and survival options, then move only when the next state is supported as safer.
Optional quick check
Section 12 of 12
At 2320 the marked bilge level is rising 0.5 cm/min with the pump on after a grounding. Steering is heavy and one crew member has a head injury. Which update is defensible?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
- RYA Yachtmaster Offshore examination scope
- RYA Coastal Skipper/Yachtmaster Offshore Theory course
- RYA equipment for UK pleasure vessels
- MCA MGN 599 Amendment 1 — pleasure-vessel safety guidance
- MCA GMDSS VHF DSC procedures for small-boat users
- RYA first aid afloat
- MCA MGN 623 — telemedical advice service at sea
- RYA sailing grab-bag guidance
Continue studying Special Situations Afloat
This public lesson is part of Revision Module 20. Full revision access adds the guided Learn, Practise and Test flow, flashcards and revision progress.