Topics Covered on This Page
Fire Onboard
The Fire Triangle and Tetrahedron
Fire requires three elements — fuel, heat, and oxygen. Remove any one and the fire dies. Modern fire science adds a fourth: the chemical chain reaction sustaining combustion. These four together form the fire tetrahedron. Understanding this determines which extinguishing agent to choose.
Remove: Shut off fuel valves, close fuel lines, move combustibles away from fire
Cut fuel supply; remove burning material
Remove: Cool faster than fire generates heat — only works on Class A with water
Water (Class A only); CO2 also has cooling effect
Remove: Smother the fire — cut off the oxygen supply
CO2, foam, closing hatches, fixed suppression systems
Remove: Chemical interruption of combustion at the molecular level
Halon substitutes (FM-200, HFC-227ea), dry chemical
The PASS Acronym — How to Use a Fire Extinguisher
PASS is the universal procedure for operating a portable fire extinguisher. Most portable extinguishers discharge for only 8 to 15 seconds — know the steps cold before you need them.
Remove the safety pin or tamper seal from the handle. This unlocks the operating mechanism and allows the handle to be depressed.
Point the nozzle or horn at the BASE of the fire, not at the flames. The agent must reach the fuel source to extinguish the fire — aiming at flames is ineffective.
Press the handle firmly and steadily. This opens the valve and releases the extinguishing agent. Most portable units discharge for only 8 to 15 seconds — every second counts.
Move the nozzle in a wide, slow sweep across the entire base of the fire. Work from the near edge toward the far edge. Continue until the fire is completely out, then watch for re-ignition.
Fire Classes A, B, C, and D
The fire class is determined by what is burning, not where the fire is. An engine room fire from a fuel leak is Class B (flammable liquid) — not Class C because it is in an engine room. Selecting the wrong class leads to the wrong agent, which can make the fire worse.
| Class | Label | Fuel Type | Correct Agents |
|---|---|---|---|
| A | Ordinary Combustibles | Wood, paper, cloth, rubber, fiberglass, plastics | Water, dry chemical, foam |
| B | Flammable Liquids and Gases | Gasoline, diesel, oil, propane, grease, paint | CO2, dry chemical, halon substitutes, foam |
| C | Energized Electrical Equipment | Live wiring, motors, panels, batteries, switchboards | CO2, dry chemical (non-conductive agents only) |
| D | Combustible Metals | Magnesium, titanium, sodium, lithium (rare on recreational vessels) | Special dry powder (graphite-based) ONLY |
Immediate Actions — Fire Onboard
Alert everyone aboard immediately. Fire grows exponentially — early warning saves lives. Designate someone to call MAYDAY if you cannot control the fire quickly.
Everyone aboard puts on a PFD before fighting the fire. If the situation deteriorates and the vessel must be abandoned, jackets are already on.
If underway, alter course or reduce speed so the fire and smoke blow away from the vessel. This slows fire spread and protects crew from smoke inhalation.
Transmit a MAYDAY if the fire is serious. Do not wait to see if you can extinguish it first — help takes time to arrive and fires grow fast.
Shut off fuel supply to the affected area. Cut electrical power at the main breaker. This removes two sides of the fire triangle — fuel and heat sources.
Use the right agent for the fire class. Pull, Aim low, Squeeze, Sweep. Stay low — heat and toxic gases rise. Maintain your exit route at all times.
Opening the engine room hatch introduces oxygen and can cause a catastrophic flashover. Activate the fixed suppression system from outside. If no fixed system, crack the hatch only enough to insert the extinguisher nozzle, then close it.
If one full extinguisher discharge does not extinguish the fire, evacuate immediately. Attempting to fight a fire you cannot win costs lives. Abandon ship and let the USCG know your position.
Engine Room CO2 Fixed System — Step-by-Step
A fixed CO2 suppression system floods the engine compartment with carbon dioxide, displacing oxygen and extinguishing the fire without opening hatches. CO2 is lethal in confined spaces — never enter a CO2-flooded engine room without SCBA.
Flooding and Watertight Integrity
Flooding is one of the most time-critical emergencies on any vessel. The rate of flooding determines how much time you have to respond — know your pumping capacity versus inflow rate. Watertight integrity means keeping flooding confined to one compartment through closed watertight doors, hatches, and bulkheads.
Check through-hull fittings, seacocks, stuffing boxes, transducer fittings, hull-to-deck joint, and any collision damage. Get below and find it fast.
Use softwood plugs (keep one attached to every seacock), rags, seat cushions, or a collision mat over an external breach. Even slowing the inflow buys time for pumping.
Activate electric bilge pumps, engine-driven bilge pumps, and portable pumps simultaneously. Know the pump-out rate versus the inflow rate — if inflow exceeds pump capacity, the situation is critical.
Limit flooding to one compartment by closing all watertight integrity features. This may keep the vessel afloat even if one compartment is fully flooded.
If flooding cannot be controlled, transmit MAYDAY on VHF Channel 16 immediately. Include your position, number of persons aboard, and nature of the emergency.
Put on PFDs, gather the grab bag (EPIRB, flares, water, first aid), and deploy the life raft while the vessel still has freeboard. Do not wait until the vessel is nearly submerged.
Collision Mat
A collision mat is a heavy canvas or rubber mat used to cover an underwater breach in the hull from the outside. The water pressure holds it in place against the hull.
Fire Pumps and Portable Pumps
High-capacity pump driven by the main engine; delivers hundreds of gallons per minute. Used to fight fires with a fire hose and also serves as a dewatering pump in flooding emergencies. Always check that seacocks are open before starting.
Automatic or manual electric pump; typically 500 to 2,000 GPH on recreational vessels. Activates on a float switch. First line of defense against minor flooding — not sufficient alone for serious flooding.
A gasoline or electric portable pump that can be placed directly in the flooded space. Typical capacity 50 to 200 GPH for small units; much higher for commercial portable pumps. Essential when fixed systems are overwhelmed.
Last resort when all mechanical pumps have failed. More effective than it sounds for small flooding rates — a coordinated crew can move significant volumes of water. Any container works: buckets, pots, fenders cut in half.
The decision to abandon ship is one of the hardest a captain makes. General guidance: if flooding cannot be controlled by all available pumps and plugging measures, and the vessel is losing freeboard, abandon ship before the vessel is awash.
The cardinal rule: abandon ship TO the life raft, not FROM it.Board the raft while the vessel still has freeboard for a controlled transfer. A vessel that is nearly submerged provides no stable platform for raft deployment.
Man Overboard
Man overboard is one of the most time-sensitive emergencies at sea. Cold water accelerates hypothermia rapidly — a person in 50-degree water loses consciousness in 30 to 60 minutes. Speed, organization, and keeping the person in sight are the three priorities. See also: Man Overboard Rescue Guide.
Immediate Actions — Man Overboard
Immediately alert all crew. The more eyes tracking the person in the water, the better. Sound is also a signal to other nearby vessels.
Throw the nearest ring buoy, horseshoe buoy, or any floating object immediately. A Type IV throwable PFD, fender, or even an ice chest can keep someone afloat. Throw close to the person — do not hit them.
One crew member does NOTHING except keep the person in sight and point at them continuously. They do not speak on the radio, they do not handle lines — they only watch and point. Never lose sight of the person.
Press the MOB button on the chartplotter or GPS immediately. Note the time and bearing. Drop a smoke float or dye marker if available. Every second of drift makes recovery harder.
Transmit a PAN-PAN on VHF Channel 16 if the person is in sight and recovery is likely. Transmit MAYDAY if they are not in sight, conditions are severe, or recovery will take time. Alert the USCG to stand by.
Choose the appropriate maneuver: Quick Stop for good visibility and calm conditions, Williamson Turn for reduced visibility or when the person is not visible. Approach from downwind and downcurrent to avoid overrunning the person.
Come alongside with the person to leeward of the vessel to create a lee. Shut down engines before the person reaches the propeller arc. Use a boarding ladder, swim platform, or rescue sling to recover. For an unconscious or exhausted person, use a rescue strop or sling.
Recovery Maneuvers
Keeps the person close to the vessel throughout the maneuver; simple for small crews
Propeller risk during the initial sharp turn; vessel may overshoot in strong wind
Returns vessel along the exact same track; best for night and reduced visibility
Takes longer than Quick Stop; requires precise helmsman execution
Abandon Ship
Abandoning ship is the last resort — but when it is necessary, an organized and early departure saves lives. The life raft is designed to survive conditions that a vessel cannot. Preparation begins long before the emergency: the life raft should be inspected annually, the EPIRB registered and tested, and all crew briefed on procedures.
The cardinal rule: abandon ship to the life raft, not from it. Abandon the vessel while it still has freeboard. An organized departure from a stable vessel is far safer than an emergency jump from a sinking one.
Transmit MAYDAY on VHF Channel 16 with your exact position, number of persons, vessel description, and nature of distress. If time permits, transmit on both Channel 16 and Channel 22A (USCG working channel).
Manually activate the EPIRB if Category II, or ensure it is free-floating if Category I (activates automatically in water). The EPIRB transmits your position to the COSPAS-SARSAT satellite system and the USCG Rescue Coordination Center.
Everyone puts on an immersion suit (survival suit) or life jacket before going into the water. Hypothermia is a primary killer in cold water — immersion suits significantly extend survival time.
The grab bag should contain: EPIRB, handheld VHF radio, flares and pyrotechnics, water and emergency rations, first aid kit, knife, compass, whistle, and any medications. Grab it on the way out — do not go back for it.
Throw the life raft canister overboard while keeping the painter (activation line) secured to the vessel. Pull the painter sharply to inflate the raft. Board the raft from the vessel if possible — step into the raft, do not jump on it.
Once all persons are aboard the raft, cut the painter free of the vessel. A sinking vessel can drag a life raft under. Use the raft knife stored in the raft canister.
If multiple life rafts, secure them together. Stay in the vicinity of the vessel wreck — rescuers will search there first. Deploy sea anchor to reduce drift. Fire flares when you hear or see rescuers. Preserve water and maintain body heat.
EPIRB — Emergency Position Indicating Radio Beacon
Survival in the Life Raft
Rescuers will search the reported position first. Deploy sea anchor to minimize drift. Only paddle away if there is danger from sinking debris or fire.
Do not drink seawater — it accelerates dehydration. Collect rainwater. Ration emergency water strictly. The first 24 hours without water are manageable; rationing extends survival.
Stay out of the water. Use the raft canopy if available. Huddle together for warmth. A dry person in a raft survives far longer than a person in the water, even in warm climates.
Fire flares only when a rescuer is in sight — do not waste them signaling into empty sky. Use the signal mirror in daylight. Activate the EPIRB and keep it transmitting until rescue is complete.
Distress Signals
Distress signals are divided into radio signals (MAYDAY, DSC) and visual signals (flares, smoke, mirror, flag). USCG regulations require recreational vessels operating on coastal waters to carry approved visual distress signals (VDS). Know which signals work day only, night only, or day and night.
MAYDAY Call Format — VHF Channel 16
Visual and Electronic Distress Signals
Say MAYDAY three times; follow the MAYDAY format exactly for fastest response
Digital Selective Calling sends an automatic distress alert with MMSI and GPS position to any DSC-equipped vessel or shore station; press and hold the red DISTRESS button for 5 seconds
SOLAS-compliant; reaches 1,000 feet altitude; visible for 40 seconds; burns red; do not fire directly overhead in heavy rain or cloud
Hold downwind and away from body and life raft; burns 60 seconds; direct heat — wear gloves if available; one of the most effective close-range signals
Highly effective for aircraft spotting; deploy upwind of raft so smoke does not engulf survivors; burns 3 to 4 minutes
Black square and circle on orange background; wave it or display it prominently on a raft or vessel
Most effective long-range alerting device; satellites relay position to USCG within minutes; keep activated until rescue is complete
Visible up to 10 miles in good conditions; aim by looking through the sighting hole and directing the reflected spot toward the target
Three short, three long, three short flashes (dot-dot-dot dash-dash-dash dot-dot-dot); repeat continuously
Recreational vessels 16 feet and over on coastal waters, the Great Lakes, and US territorial sea must carry USCG-approved visual distress signals.
Minimum requirement: three day signals, three night signals, or three day-and-night combination signals.
Pyrotechnic signals expire 42 months from date of manufacture (printed on the device) — check expiration dates before every voyage.
Expired pyrotechnics do not count toward the legal requirement but should be kept aboard as backup signals.
Medical Emergencies
Medical emergencies at sea require rapid assessment, stabilization, and communication with shore-side medical professionals. The USCG acts as a relay to the Tele-Medical Assistance Service (TMAS), which provides physician-level medical guidance via radio. For severe emergencies, medevac by USCG helicopter may be requested.
Use the ABCs: Airway (is it open?), Breathing (are they breathing?), Circulation (is there a pulse, are they bleeding?). Stabilize immediately — stop major bleeding, start CPR if indicated.
Transmit a PAN-PAN (urgent, not immediately life-threatening) or MAYDAY (life-threatening) to the USCG. Describe the patient symptoms, location, number of persons, and vessel information. The USCG will connect you to medical advice.
The US Coast Guard can connect you to the Tele-Medical Assistance Service (TMAS) — staffed by emergency physicians who provide real-time medical guidance via radio or satellite phone to mariners at sea.
If the patient requires care beyond what can be provided aboard, request a medevac (medical evacuation). The USCG will coordinate helicopter or vessel pickup. Be prepared to provide your exact position, wind and sea conditions, and patient status.
Move the patient to a clear area with enough overhead clearance for a helicopter hoist. Secure loose items and cover the patient to prevent rotor downwash hypothermia. Have patient information (medications, allergies, medical history) ready for the medevac crew.
- •Patient name, age, and sex
- •Chief complaint and symptoms with onset time
- •Vital signs: pulse, breathing rate, level of consciousness
- •Medications and allergies
- •Relevant medical history
- •Vessel position, speed, and nearest port
- •Sea state and weather conditions
- •Estimated time to reach port
TMAS provides 24-hour physician-staffed medical guidance to mariners anywhere in US waters and on the high seas. The USCG will connect you via radio or satellite phone.
TMAS can advise on: trauma management, cardiac events, stroke recognition, medication administration from the first aid kit, and whether medevac is required or whether the patient can be safely transported to port.
Running Aground
Running aground is one of the most common maritime casualties. The immediate priority is to determine whether the vessel is flooding. A grounded vessel that is watertight is not sinking — address flooding first, then work to free the vessel. Tide state is a critical factor: a rising tide can refloat the vessel without further action.
Stopping prevents further forward movement that worsens grounding and prevents propeller damage from sand, rock, or coral. Mark your position on the chartplotter.
Inspect the bilge immediately. If the hull is breached below the waterline, flooding takes priority over getting free. A grounded vessel that is not flooding is not sinking — address flooding first.
Sudden grounding can throw crew members. Check everyone for injuries before proceeding.
Determine whether the tide is rising or falling. If rising, wait — the vessel may float free on its own. If falling, act quickly before the vessel settles harder on the bottom.
Attempt to back off along your track by reversing engines slowly. If the vessel does not move freely, do not force it — excessive throttle can damage the propeller, shaft, or stuffing box.
Kedging is the technique of setting an anchor in deeper water and winching the vessel off using the anchor rode. Use the dinghy or a long line to carry the anchor to deeper water in the direction from which you came, then winch back using the windlass or a block and tackle.
Reducing draft by heeling the vessel can help. Move crew and gear to one side, use a halyard to pull the mast over (on a sailboat), or use the boom as a lever. Even a few inches of draft reduction can be enough.
If unable to free the vessel independently, call Sea Tow, TowBoat US, or the USCG. Do not wait until the vessel is in a worse position. Provide your exact position, vessel type and size, and the nature of the grounding.
Helicopter Operations
Helicopter hoist operations require close coordination between the vessel crew and the helicopter crew. The most critical safety point: do not touch the hoist cable or basket until it has contacted the water or deck to discharge static electricity — rotor static charge can cause a severe electrical shock. See also: Search and Rescue Operations Guide.
Emergency Towing
Emergency towing is the operation of towing a disabled vessel to safety using another vessel. Unlike commercial towboat operations, impromptu emergency towing requires careful seamanship to prevent towline parting, damage to both vessels, or injury to crew. Towing is hard on equipment — use the strongest available gear and take up loads gradually.
Contact the assisting vessel on VHF Channel 16, then move to a working channel. Agree on the towing arrangement, speed, and any signals before connecting the tow.
The disabled vessel should rig a bridle — two lines from port and starboard bow cleats meeting at a central point. The bridle distributes tow load and prevents yawing. Use the strongest available lines.
A heaving line is thrown from the towing vessel to pass the towline. The towed vessel secures the towline to the bridle. Use at least 300 feet of tow line — longer in rough seas. A catenary (sag) in the line absorbs shock loads.
The towing vessel takes up slack very slowly. A sudden jerk on the towline can part it or damage cleats. Ease into the tow gradually over several minutes.
Post a crew member aft to watch the towline at all times. Check for chafe at the bow chock or fairlead. Keep a knife ready to cut the towline in an emergency. The towed vessel should steer to track behind the towing vessel.
Towing speed should be slow — typically 3 to 5 knots in calm water, slower in rough seas. A disabled vessel under tow handles poorly and can yaw violently. The towing vessel must communicate any course changes in advance.
Two lines from port and starboard bow cleats meeting at a central point — distributes load and prevents yawing under tow
Wrap the towline with rags, leather, or commercial chafe gear where it passes through a bow chock or over a fairlead — the chafing point is where towlines part
Keep a sharp knife immediately accessible to cut the towline in an emergency — if the towing vessel grounds or founders, the towline must be cut immediately
Keep a helmsman at the wheel of the towed vessel to steer and prevent yawing — an unsteered vessel under tow can sheer dangerously and part the line
Exam Quick Reference — High-Frequency Topics
Pull-Aim-Squeeze-Sweep. Aim at the BASE of the fire. The most tested fire extinguisher question on the OUPV exam.
An engine room fuel fire is Class B. A burning life ring is Class A. An electrical panel fire is Class C. Location is irrelevant — only what is burning determines the class.
Opening the hatch introduces oxygen to a fuel fire and can cause flashover. Activate the CO2 system from outside. If no CO2, crack the hatch only to insert the extinguisher nozzle.
A CO2-flooded engine room has no oxygen. A crew member entering without SCBA will lose consciousness in seconds. Never enter until the space is confirmed ventilated.
The Williamson Turn returns the vessel on a reciprocal course along the same track — best for night and reduced visibility when the person is not visible from the bridge.
Assigning a pointer who does nothing but keep the person in sight is the critical step most candidates underestimate. Never look away from the person in the water.
Board the life raft while the vessel still has freeboard. Do not wait until the vessel is awash. An organized departure from a stable vessel is exponentially safer than an emergency jump from a sinking one.
A helicopter hoist cable carries a dangerous static charge from the rotor. Allow it to touch the water or deck before touching it. This point appears frequently in helicopter hoist questions.
Category I is float-free and activates automatically when submerged. Category II is manual activation only. Cat I is preferred offshore; Cat II is acceptable for coastal use.
If the tide is rising when you go aground, wait — the vessel may float free without further action. If the tide is falling, act immediately before the vessel settles harder and heels further.
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