STCW Leadership and Managerial Skills (HELMS)

Correct: Tricing pendants are short, fixed-length lines designed to pull the lifeboat into the embarkation deck for safe boarding. Because they are short, they must be released before the boat is lowered further; otherwise, the boat would hang at a dangerous angle or be held against the ship’s side as the falls are paid out. Bowsing tackles are used to hold the boat alongside while the pendants are released, allowing for a controlled transition to the falls.

Incorrect: Maintaining the pendants until the boat is near the water is physically impossible and dangerous because the fixed length of the pendants would cause the boat to tilt sharply as the falls lower. Focusing only on extending telescopic canopy supports is incorrect because the canopy does not provide the necessary structural clearance or control for the falls during descent. The strategy of transferring the boat’s weight to deck cleats is unsafe as the craft must remain suspended by the falls to ensure a rapid and synchronized launch during an actual emergency.

Takeaway: Tricing pendants must be replaced by bowsing tackles and released before lowering a lifeboat from the embarkation deck to the water.

Correct: For a totally enclosed lifeboat to function as designed in a fire or toxic gas environment, it must be completely sealed to maintain its airtight integrity. The compressed air system provides positive pressure to prevent the entry of smoke or fumes and supplies air for the engine and crew. The external water spray system must be activated before the craft enters the fire zone to create a protective thermal barrier over the hull, and the engine must be running to ensure immediate maneuverability upon release.

Incorrect: The strategy of leaving hatches open for visibility is extremely dangerous as it compromises the fire-protected environment and allows toxic smoke to enter the cabin. Delaying the engine start until the boat is waterborne is a critical error because the engine must be tested and running to ensure the craft can immediately move away from the hazard once released. Choosing to keep the water spray system off during the descent through a fire zone exposes the hull to intense heat, which can lead to structural failure or internal temperature spikes before the boat even reaches the water.

Takeaway: Totally enclosed lifeboats must be fully sealed with air and spray systems active when launching into fire or gas hazards.

Correct: Frapping lines are specifically designed to control the athwartship movement of a lifeboat during the launching process. When a vessel is listing, the lifeboat naturally wants to swing away from or crash into the hull. By properly tending these lines, the crew can keep the craft tucked into the ship’s side, ensuring a stable platform for embarkation and a controlled descent to the water line as required by USCG and STCW safety standards.

Incorrect: The strategy of rapidly releasing the brake is dangerous because it sacrifices control over the descent speed and does not address the lateral swinging of the craft. Choosing to disconnect tricing pendants prematurely would cause the lifeboat to swing out away from the embarkation deck, making it nearly impossible for passengers to board safely. Focusing only on the emergency hand crank is an incorrect application of equipment, as the hand crank is intended for recovery or when gravity fails, and it does not provide the necessary lateral restraint provided by frapping lines.

Takeaway: Frapping lines are essential for controlling a lifeboat’s swing and maintaining its proximity to the hull during emergency launching.

Correct: Under United States Coast Guard safety standards for survival craft, ensuring the drain plug is closed is a fundamental pre-launch requirement. This prevents the lifeboat from taking on water and losing buoyancy immediately upon contact with the sea. For open lifeboats, maintaining hull integrity is the primary defense against swamping in heavy seas.

Incorrect: The strategy of stowing the painter inside the boat is incorrect because the painter must be led forward and secured to the ship to keep the boat alongside during embarkation. Choosing to bypass limit switches is a dangerous violation of safety protocols that could lead to equipment failure or structural damage to the davits. Focusing only on venting air tanks is counterproductive and potentially harmful, as these tanks provide the inherent buoyancy required for the craft to float even if the hull is breached.

Takeaway: The installation of the drain plug is the most critical step for maintaining the watertight integrity of an open lifeboat during launch.

Correct: Under USCG regulations and international standards, a rescue boat must have a minimum length of 3.8 meters and a maximum of 8.5 meters. It is required to accommodate at least five seated persons and one person lying on a stretcher, while maintaining a speed of 6 knots for 4 hours.

Incorrect: Relying solely on a minimum length of 5 meters and a speed of 8 knots for only 2 hours fails to meet the specific endurance and size requirements. Choosing to require fire-retardant construction and a fixed VHF radio for all rescue boats incorrectly applies standards typically reserved for totally enclosed lifeboats. Focusing only on seating for the entire crew muster list or mandatory GPS integration misinterprets the primary function of a rescue boat for recovery operations.

Takeaway: Rescue boats must meet specific length, seating, and 6-knot/4-hour performance standards to ensure effective recovery and towing capabilities.

Correct: Limit switches are mandatory safety components in launching appliances designed to automatically interrupt the power supply to the winch motor. This prevents the motor from continuing to pull once the davit arms have reached their final travel limit, which would otherwise result in snapped falls or structural damage to the vessel’s boat deck fittings.

Incorrect: Relying on centrifugal brakes is incorrect as these are designed to regulate the speed of descent during a gravity launch rather than stopping the motor during recovery. The strategy of using dead-man controls is insufficient because while they require the operator to maintain pressure to keep the motor running, they do not provide an automated physical stop at the stowed position. Choosing governor valves is a mistake as these are typically found in engine speed regulation and are not the primary electrical cut-off mechanism for lifeboat winches.

Takeaway: Limit switches are essential safety devices that prevent mechanical failure by automatically cutting winch power during survival craft recovery operations.

Correct: Rear-facing seats are mandatory in free-fall lifeboats because they ensure that the force of impact is distributed across the strongest parts of the body, specifically the back and head.

Incorrect: Choosing to face the boarding hatch for faster evacuation ignores the primary risk of spinal injury during the high-speed launch sequence. Focusing only on the coxswain’s visibility fails to address the mechanical necessity of protecting crew members from extreme G-forces. The strategy of reducing motion sickness through seat orientation is secondary to the critical requirement of preventing traumatic impact injuries during the launch.

Correct: Under USCG regulations and international standards, lifeboat buoyancy must be inherent and provided by material that is resistant to oil and petroleum products. This ensures that the buoyancy remains effective even if the hull is breached in an environment where oil or fuel may be present on the water surface, maintaining the craft’s ability to support its full complement and equipment while flooded.

Incorrect: The strategy of making buoyancy material removable for hull inspections is incorrect because buoyancy must be a permanent, integral part of the craft’s construction to prevent accidental displacement. Proposing the use of pressurized air tanks is a misconception that confuses rigid lifeboat construction with inflatable liferaft technology, which relies on different buoyancy principles. Focusing buoyancy only in the bow and stern would result in poor longitudinal stability and would likely cause the boat to pitch or capsize if flooded, rather than remaining level and stable.

Takeaway: Lifeboat buoyancy must be inherent, oil-resistant, and sufficient to support the craft and its full complement even when completely flooded.

Correct: According to United States Coast Guard regulations and the LSA Code, lifeboats must have inherent buoyancy to keep the boat and its equipment afloat when flooded. This buoyancy is provided by internal buoyancy units, such as tanks or closed-cell foam, which must be resistant to oil and petroleum products to prevent degradation in a machinery-space discharge scenario.

Incorrect: Relying solely on hull displacement and manual pumping is insufficient because survival craft must remain buoyant even when completely swamped. Utilizing inflatable chambers along the gunwale is a design feature typically reserved for rigid-inflatable rescue boats rather than standard open lifeboats. Choosing to depend on the buoyancy of wooden construction materials fails to meet the specific requirement for dedicated, non-absorbent buoyancy units that provide a calculated reserve of flotation.

Takeaway: Open lifeboats must contain dedicated internal buoyancy units resistant to oil to ensure they remain afloat even if the hull is swamped.

Correct: Under U.S. Coast Guard safety regulations and standard maritime emergency procedures, ensuring the drain plug is closed is the primary step to prevent the craft from flooding upon water entry. Simultaneously, securing the painter forward is essential to keep the lifeboat alongside the vessel and properly oriented as it reaches the water, preventing it from drifting into the propeller or away from the ship.

Incorrect: Releasing the gripes before confirming the boat is watertight and the painter is secured can cause the boat to swing dangerously or drift out of reach. The strategy of running the engine at high speeds while the boat is still suspended in the davits is hazardous because it risks engine overheating due to lack of cooling water and creates unnecessary vibration. Choosing to lower the craft to the water before verifying the drain plug is a critical safety failure that leads to immediate flooding and potential loss of the survival craft.

Takeaway: Securing the drain plug and painter is the mandatory first step to ensure lifeboat buoyancy and control during emergency launching.

Correct: Under United States Coast Guard regulations and international standards for rigid lifeboats, the craft must have inherent buoyancy or be fitted with internal buoyancy units. This buoyancy must be sufficient to float the lifeboat with all its equipment and the full complement of persons when flooded. Crucially, the material used for buoyancy must be resistant to oil and petroleum products to prevent degradation in the event of a spill or engine leak.

Incorrect: The strategy of using a simple air gap in a double hull is insufficient because a single breach would compromise the entire buoyancy system. Opting for inflatable collars describes a different class of rescue boat or hybrid craft rather than a standard rigid lifeboat. Focusing only on hull thickness and displacement fails to account for the requirement that the craft must remain buoyant even when completely swamped or flooded.

Takeaway: Rigid lifeboats must contain oil-resistant internal buoyancy to ensure they remain afloat even when flooded or damaged.

Correct: Gravity davits are designed to function without external power by utilizing the weight of the survival craft to initiate and maintain the launch. The speed of the descent is controlled by a centrifugal brake to prevent overspeeding, while the operator uses a weighted manual brake lever to start, stop, or modulate the rate of fall. This ensures the boat can be safely deployed even during a dead-ship scenario as required by USCG and STCW standards.

Incorrect: Relying on an internal hydraulic dampening system is incorrect as standard gravity davits use mechanical centrifugal and friction brakes rather than hydraulics for descent control. The strategy of using the electric winch motor as a regenerative brake is invalid because the motor is mechanically disconnected or free-wheeling during a gravity launch to ensure power is not required. Choosing to use the manual hand crank during the fall is extremely dangerous and prohibited, as the crank would spin at high speeds and could cause fatal injuries to the operator; safety interlocks are usually in place to prevent this.

Takeaway: Gravity davits utilize the craft’s weight for launching, with descent speed controlled manually through a weighted friction brake lever.

Correct: In accordance with United States Coast Guard safety standards and STCW guidelines, frapping lines are essential for controlling the lateral motion of a lifeboat. When a vessel lists, the boat tends to swing away from the hull; tensioning these lines keeps the craft stable and prevents it from crashing back into the ship’s side, ensuring a safer descent for the occupants.

Incorrect: Relying only on tricing pendants is insufficient because they are designed specifically to bring the boat to the embarkation deck and must be released before the boat is lowered to the water. The strategy of deploying a sea anchor while the boat is still suspended is ineffective as it requires water resistance to function and would create a significant snag hazard. Choosing to stop the boat repeatedly with the hand brake during an emergency descent increases the time spent in the danger zone and subjects the davit system to unnecessary shock loading.

Takeaway: Frapping lines are critical for stabilizing a lifeboat against swinging during launch, especially when the vessel is listing or rolling in heavy seas.

Correct: In accordance with U.S. Coast Guard safety standards for survival craft, limit switches are designed to automatically cut power to the winch before the boat reaches the structural stops. This prevents the winch from over-tensioning the wire falls or damaging the davit arms and boat hull through excessive mechanical force.

Incorrect: Relying on maximum speed until physical contact occurs risks catastrophic failure of the wire falls or davit structure due to sudden impact and kinetic energy. Choosing to bypass safety limit switches removes the primary protection against operator error and mechanical over-travel, which is a violation of standard safety protocols. Opting to apply the centrifugal brake while the motor is engaged is incorrect because the brake is intended for controlled gravity descent, not for stopping a powered hoist, and would cause excessive heat and mechanical wear.

Takeaway: Limit switches are critical safety components that prevent mechanical damage by automatically stopping the winch before the rescue boat hits the davit stops.

Correct: Under United States Coast Guard and international safety standards, totally enclosed lifeboats are engineered to be self-righting. This capability depends on the craft being watertight and the occupants being securely belted into their seats to maintain the designed center of gravity. If the boat capsizes, the hull geometry and weight distribution will naturally return it to an upright position.

Incorrect: The strategy of using an active ballast system is incorrect because such systems are too complex for survival craft and would likely fail during a power loss or extreme motion. Relying on an automatic retractable sea anchor is a secondary safety measure that does not address the fundamental physical stability or self-righting requirements of the hull. Opting for a double-hull filled with pressurized nitrogen is not a standard construction method, as lifeboats typically use closed-cell foam for inherent buoyancy rather than pressurized gases.

Takeaway: Totally enclosed lifeboats provide critical safety through self-righting capabilities, which require passengers to be belted and hatches to be sealed.

Correct: Under U.S. Coast Guard regulations (46 CFR) and the LSA Code, all lifeboats, including motor-propelled totally enclosed versions, must carry a set of buoyant oars. These oars must be sufficient to make headway in calm seas and include thole pins or crutches attached by lanyards. This requirement provides a necessary manual backup for maneuvering the craft away from hazards or maintaining position if the engine fails.

Incorrect: Opting for a fixed EPIRB wired to the starter battery is not a standard requirement, as distress signaling is typically handled by ship-wide float-free units or portable SARTs. The strategy of providing five liters of water per person is an overestimation of the legal requirement, which is set at three liters per person. Choosing to include a portable gasoline-powered bilge pump is incorrect because internal combustion engines for auxiliary equipment are generally restricted due to fire safety and fuel storage risks within the craft.

Takeaway: Lifeboats must maintain manual propulsion capability through buoyant oars to ensure basic maneuverability during a primary engine failure.

Correct: Under United States Coast Guard and STCW standards, securing the canopy of a partially enclosed lifeboat is vital to prevent swamping from spray or boarding seas. Leading the painter forward allows the boat to shear away from the ship’s side as it hits the water. Simultaneous release of the hooks is the standard safety procedure to prevent the boat from being suspended by one end, which often leads to capsizing or structural failure.

Incorrect: The strategy of leaving the canopy retracted significantly increases the risk of the boat taking on water and losing stability in rough conditions. Releasing the forward hook before the aft hook is a dangerous error that can cause the boat to broach or be dragged stern-first. Relying on taut tricing pendants during the entire descent is incorrect as they must be tripped to allow the boat to reach the water. Opting to rig a sea anchor to the ship’s railing creates a lethal entanglement hazard that could pin the survival craft against the sinking vessel.

Takeaway: Securing the canopy and properly leading the painter are critical steps to ensure stability and a safe departure from the ship’s side.

Correct: According to United States Coast Guard (USCG) and international safety standards for totally enclosed lifeboats, the craft is designed to survive a fire-on-water scenario for at least 10 minutes. This requires the craft to be completely sealed to prevent smoke ingress. The compressed air system must be activated to provide breathable air for the occupants and the engine, while also creating positive pressure to keep out toxic fumes. Simultaneously, the water spray system must be engaged to provide a continuous film of water over the hull, protecting the fiberglass and occupants from intense radiant heat.

Incorrect: The strategy of keeping hatches open for ventilation is incorrect because it allows lethal smoke and heat to enter the survival craft. Choosing to shut down the engine is a failure in emergency procedures as the craft must use its own power to clear the hazard area as quickly as possible. Opting to delay the use of the air system while in a fire zone is dangerous because the engine and occupants would quickly deplete the available oxygen and succumb to carbon monoxide poisoning.

Takeaway: Totally enclosed lifeboats protect occupants from fire by using a closed-air system for positive pressure and a water spray for cooling.

Correct: Under USCG safety standards, frapping lines are used to reduce the swinging motion of a lifeboat during the lowering process. By applying tension to the falls, these lines keep the boat tucked closer to the ship’s side, preventing heavy impacts that could damage the rigid hull or injure occupants.

Incorrect: The strategy of rapidly surging the brake is extremely hazardous as it risks a free-fall condition or mechanical failure of the winch system. Choosing to release the sea painter too early is incorrect because the painter is vital for keeping the boat positioned correctly under the falls until release. Focusing only on adjusting limit switches is a misunderstanding of equipment, as these are safety cut-outs for the winch and do not control the physical swing of the boat during descent.

Takeaway: Frapping lines provide the necessary lateral control to prevent a lifeboat from swinging and impacting the ship’s hull during emergency launching.

Correct: In accordance with USCG survival craft standards, the sea painter must be led well forward to act as a spring line. This keeps the boat alongside the ship for boarding and prevents the craft from being drawn into the dangerous area of the ship’s stern and propellers.

Incorrect: The strategy of using the painter as a guide line for crew to slide down is unsafe and not its intended purpose. Choosing to use the painter for high-speed towing is incorrect as painters and lifeboat fittings are not designed for the stresses of high-speed towing while the ship is underway. Focusing only on keeping the boat under the davit heads ignores the dynamic forces of the sea which will move the boat as soon as it is waterborne.

Takeaway: The sea painter is essential for keeping the lifeboat alongside the ship and clear of the propellers during launch.

Correct: In accordance with United States Coast Guard safety standards and STCW guidelines for free-fall lifeboats, the physical safety of the crew is the primary concern during the high-impact entry. The forces exerted during a free-fall launch can cause severe spinal or neck injuries if occupants are not properly restrained in their rear-facing seats with their heads supported by the integrated headrests.

Incorrect: The strategy of using the water spray system for ramp lubrication is a misconception, as the spray system is designed for fire protection and clearing toxic gases rather than reducing friction. Relying on a painter line is inappropriate for free-fall operations because the craft is designed to move away from the vessel through its own momentum upon impact. Choosing to set the engine to full throttle before water entry is dangerous, as the sudden impact can cause mechanical damage to the propulsion system or injury to the crew if the propeller is spinning at high speeds upon hitting the water.

Takeaway: Occupants must be fully restrained with heads against headrests to prevent injury from the G-forces of a free-fall water entry.

Correct: In a free-fall lifeboat, the craft enters the water at a significant speed and angle, creating high deceleration forces. To protect the occupants from spinal and neck injuries, the LSA Code requires seats to be aft-facing so the impact force is distributed across the back and the head is supported. Multi-point safety harnesses are essential to keep the occupant securely positioned against the seat’s padding throughout the entire launch and entry sequence.

Incorrect: The strategy of using forward-facing seats with lap belts is dangerous because the impact forces would cause the occupant’s torso and head to whip forward violently. Focusing only on longitudinal benches with handholds is insufficient as they provide no restraint or specialized support for the high G-forces experienced during a drop. Choosing to install swivel bases with shock absorbers is incorrect because such mechanisms are not structurally rated for free-fall impacts and do not provide the necessary fixed orientation for safety.

Takeaway: Free-fall lifeboat seats must be aft-facing and equipped with multi-point harnesses to safely distribute impact forces across the occupant’s body.

Correct: Under U.S. Coast Guard and STCW standards, ensuring the trackways are clear prevents mechanical jamming of the davit arms. Verifying limit switches ensures that power to the winch is cut before the davit arms hit the stops, preventing structural damage or wire failure.

Incorrect: Relying on the application of lubricant during the launch sequence is a maintenance task that should be performed during periodic inspections rather than during an active launch. Focusing only on the engine status is a critical part of boat readiness but does not address the mechanical integrity or safety of the launching appliance itself. Choosing to adjust the centrifugal brake tension is dangerous because these units are calibrated to specific descent speeds and should not be modified by crew during operation.

Takeaway: Safe launching requires verifying clear mechanical paths and functional safety limit switches before initiating the movement of the survival craft appliance.

Correct: A taut painter leading forward is essential because it ensures the rescue boat remains directly under the davit head. This prevents the boat from surging forward or aft as it leaves the water, which is the primary cause of dangerous swinging and hull impact in a seaway. According to standard maritime safety procedures, the painter acts as a control line that stabilizes the boat’s longitudinal position while the falls handle the vertical lift.

Incorrect: Choosing to maximize winch speed immediately is a dangerous approach that can lead to extreme shock loading on the falls and hook assembly if a wave suddenly drops the boat. The strategy of adjusting limit switches is fundamentally unsafe because these are fixed safety components designed to prevent structural damage at the stowage position, not operational controls for sea conditions. Focusing on the manual hand crank for taking up slack is inefficient and hazardous in a seaway, as manual operation cannot keep pace with wave motion and puts the operator at risk of injury from the crank handle.

Takeaway: Maintaining tension on the painter is the primary method for stabilizing a rescue boat during recovery in a seaway.

Correct: Open lifeboats are designed with internal buoyancy tanks or foam to ensure the craft remains afloat even when completely filled with water. USCG regulations require this buoyancy to be sufficient to support the boat, its equipment, and all certified persons. This makes the integrity of these tanks vital for survival in heavy seas where swamping is a significant risk.

Correct: Under United States Coast Guard and international safety standards, launching a rescue boat while making headway requires the painter to be secured well forward of the boat’s position. This creates a towing effect that keeps the boat parallel to the ship’s side and prevents it from swinging. Starting the engine in neutral ensures readiness without premature propulsion, and releasing the falls only when the boat is waterborne and the painter is under tension ensures the boat is safely towed by the ship until the crew is ready to cast off.

Incorrect: Securing the painter directly above the boat fails to provide the necessary forward lead to keep the boat stable against the ship’s movement. The strategy of releasing the painter before the falls is hazardous because the boat will lose its longitudinal alignment with the ship, leading to a high risk of broaching or being swept astern. Choosing to drop the boat from a height instead of lowering it fully into the water can result in equipment failure or crew injury. Relying on engine power alone to steer away without the stability of a forward painter lead is insufficient to overcome the hydrodynamic forces acting on the boat at 5 knots.

Takeaway: A forward-led painter is essential for stability and control when launching a rescue boat while the vessel is making headway.

Correct: Under USCG and international standards for tankers, totally enclosed lifeboats must be capable of protecting the crew when the vessel is surrounded by fire. This is achieved through a self-contained air support system that provides breathable air to the occupants and maintains a slight positive pressure to prevent the entry of toxic fumes, combined with a water spray system that pumps seawater over the exterior of the craft to keep the hull temperature within safe limits.

Incorrect: Relying on a manual ventilation system with carbon filters is insufficient because it does not provide the necessary positive pressure or cooling required to survive an oil fire. The strategy of using fire-retardant timber is outdated and does not meet modern construction standards for survival craft, which typically utilize fire-protected glass-reinforced plastic. Opting for an open-top canopy design is incorrect as it would expose the occupants to heat and flames, directly contradicting the purpose of a totally enclosed lifeboat on a tanker.

Takeaway: Totally enclosed lifeboats on tankers must include integrated air support and water spray systems to survive fire-hazardous environments during evacuation.

Correct: For totally enclosed lifeboats, especially those on tankers, the self-contained air support system must be designed so that the air remains breathable and the engine continues to run normally for a period of at least 10 minutes. This ensures the craft can safely navigate away from a fire on the water or through toxic gas clouds without suffocating the occupants or stalling the engine due to lack of oxygen.

Incorrect: Choosing a five-minute duration is insufficient as it does not provide enough time for a lifeboat to clear a large-scale fire or hazardous vapor zone at standard maneuvering speeds. Opting for a twenty-minute or thirty-minute requirement describes a capacity that exceeds the minimum regulatory standards set for standard air-support bottles in survival craft. The strategy of assuming longer durations might seem safer but does not reflect the specific technical specifications required for certification under current maritime safety codes.

Takeaway: Totally enclosed lifeboats must provide a self-contained air supply for at least 10 minutes to protect occupants during hazardous transits.

Correct: In a gravity davit system, tricing pendants are designed to automatically pull the lifeboat into the embarkation deck as it is lowered from the stowed position. This is critical during a list to ensure the boat is close enough for crew and passengers to board safely. Once the boat is loaded, frapping lines are used to hold the boat steady while the tricing pendants are released to allow the boat to be lowered to the water.

Incorrect: The strategy of disconnecting limit switches is dangerous as these are safety features designed to prevent structural damage to the davit and do not assist in positioning the boat for boarding. Focusing on the manual hand crank for lowering is incorrect because gravity davits rely on controlled brake release for descent, and cranking is too slow for emergency abandonment. Choosing to manipulate the hydrostatic release unit at the embarkation deck is a misunderstanding of its function, as it is intended to release the lashings or the painter once the craft is waterborne or to allow the boat to float free.

Takeaway: Tricing pendants and frapping lines are the primary tools for stabilizing a lifeboat at the embarkation deck during emergency boarding.

Correct: According to USCG regulations and international standards for the construction of rigid lifeboats, internal buoyancy must be provided by inherent buoyant material or watertight enclosures. This material must be resistant to deterioration by oil or petroleum products and must provide sufficient buoyancy to keep the lifeboat afloat even if the hull is breached and the craft is fully flooded.

Incorrect: Relying on manually inflatable air chambers is a design feature typically reserved for inflatable liferafts or certain rescue boats rather than standard rigid lifeboats. The strategy of using granulated cork is an obsolete maritime practice that does not meet modern requirements for non-absorbent, fire-retardant, and oil-resistant materials. Focusing only on a double-walled hull without internal filling fails to provide the necessary safety margin required for a craft to remain buoyant when the outer skin is compromised.

Takeaway: Rigid lifeboats must utilize oil-resistant, inherent buoyancy materials to ensure the craft remains afloat even when completely flooded or damaged at sea.