Section 9.5 Heavy Weather Precautions for Loaded Bulk Carriers

Navigating a loaded bulk carrier through heavy weather is one of the most demanding and potentially hazardous aspects of a Master Mariner’s responsibilities. The immense forces exerted by wind and waves on a large, heavily laden vessel can lead to structural damage, cargo shifting, loss of stability, and, in extreme cases, catastrophic failure. Bulk carriers, due to their size, relatively low freeboard when loaded, large hatch areas, and the nature of their cargoes, have specific vulnerabilities that require proactive and meticulous preparation before encountering heavy weather, as well as prudent seamanship during the passage. This section outlines the key precautions and actions necessary to safeguard the vessel, its crew, and its cargo when severe weather conditions are anticipated or encountered.

1. Understanding the Risks in Heavy Weather:

Loaded bulk carriers face several distinct risks in heavy seas:

Structural Damage:

Slamming/Pounding: The forepart of the vessel, especially in ballast condition but also possible when laden if pitching heavily, can slam into waves, causing immense impact forces that can lead to bottom plating damage, forepeak tank damage, and cracking in the forward structure.

Green Seas on Deck: Large waves breaking over the forecastle and main deck can damage deck fittings, air pipes, ventilator cowls, hatch cover securing arrangements, and even deform hatch covers themselves, leading to water ingress.

Longitudinal Stresses (Hogging/Sagging): While designed to withstand wave-induced bending moments, extreme wave conditions can impose stresses approaching or exceeding design limits, particularly if the vessel is already experiencing high still water bending moments or if its structural integrity is compromised by age or corrosion.

Torsional Stresses: Quartering seas can induce twisting forces on the hull.

Fatigue Damage: Repeated stress cycles in prolonged heavy weather can contribute to fatigue cracking in structural members.

Cargo Shifting: As discussed in Section 9.3, severe vessel motions can cause bulk cargoes to shift, especially if not properly trimmed or if the cargo has a low angle of repose. This can lead to a dangerous list and loss of stability.

Water Ingress into Holds:

Damaged or improperly secured hatch covers are a primary route for water ingress.

Broken air pipes or ventilators can also allow significant water entry.

Structural failure (e.g., cracks in shell plating) can lead to flooding.

The consequences of water ingress include cargo damage, loss of stability due to free surface effect or added weight, and increased stress on bulkheads if one hold floods.

Loss of Stability: Caused by cargo shifting, water ingress, or a combination.

Machinery Malfunction: Severe vessel motions can affect machinery operation (e.g., lubrication issues, cooling water intake problems if rolling heavily, stress on propulsion shafting). Loss of propulsion or steering in heavy weather is an extremely dangerous situation.

Damage to Deck Equipment and Superstructure: Fittings, pipelines, accommodation ladders, and even parts of the superstructure can be damaged by wave impacts.

Crew Safety: Injuries to crew from falls, being struck by unsecured objects, or being washed overboard are significant risks.

2. Preparations Before Encountering Heavy Weather:

Proactive preparation is key to mitigating the risks. When heavy weather is forecast or anticipated based on the voyage route and season:

A. Weather Routing and Voyage Planning:

Obtain Latest Forecasts: Utilize all available sources (weather fax, Navtex, satellite services, internet weather sites, routing services) to get the most accurate and up-to-date weather forecasts and storm warnings.

Strategic Route Adjustment: If possible, alter course and/or speed well in advance to avoid the worst of the storm system or to pass through it in the most manageable sector (e.g., avoiding the “dangerous semi-circle” of a tropical cyclone). This is the most effective precaution.

Consider Seeking Shelter: In extreme cases, seeking shelter in a protected anchorage or port of refuge might be the most prudent option, if feasible.

B. Securing the Vessel (Exterior):

Hatch Covers:

Confirm all hatch covers are fully closed and properly secured with all cleats, wedges, and cross-joint seals correctly tightened.

Inspect gaskets and compression bars for any obvious defects.

Consider applying extra sealing measures (e.g., high-quality hatch cover tape, Ram-Nek tape) if there are any doubts about weathertightness or if exceptionally severe weather is expected, especially on older vessels.

Access Hatches and Doors: Ensure all access hatches to cargo holds, forecastle store, chain lockers, mast houses, and any other deck openings are securely closed and dogged down. All external doors to accommodation and engine room must be kept closed and secured.

Ventilators and Air Pipes: Close and secure all cargo hold ventilator cowls/flaps and air pipe heads to prevent water ingress. Ensure their closing appliances are in good condition.

Deck Cargo (if any, though rare for bulkers): Ensure any cargo or equipment stowed on deck is exceptionally well secured.

Anchors: Secure anchors firmly in their hawsepipes with chain stoppers, windlass brakes, and any additional securing arrangements (e.g., hawsepipe covers, devil’s claws) fully engaged.

Mooring Lines and Deck Equipment: All mooring lines, wires, and any loose equipment on deck (drums, tools, spare parts) must be securely stowed and lashed down.

Gangway/Accommodation Ladder: Securely stowed in its sea position.

Freeing Ports and Scuppers: Ensure all freeing ports and deck scuppers are clear and unobstructed to allow rapid drainage of any water shipped on deck.

C. Securing Within the Vessel (Interior):

Stores and Equipment: Secure all loose items in storerooms, workshops, galley, accommodation, and engine room to prevent them from shifting and causing damage or injury.

Cargo Hold Bilges: Ensure bilge wells are covered by their strum boxes and that bilge suctions are clear and have been tested. Pump out any existing water from hold bilges.

Engine Room Bilges: Pumped down to minimize free surface.

Tank Soundings: Verify levels in ballast, fuel, and fresh water tanks. Minimize slack tanks where possible to reduce free surface effect, consistent with stability and stress requirements.

D. Stability and Stress Considerations:

Verify Stability Condition: Ensure the vessel has adequate GM and meets all stability criteria for the current loaded condition. A vessel with good stability is better able to withstand heavy rolling.

Stress Distribution: Be aware of the current still water bending moments and shear forces. While the vessel is designed for sea conditions, minimizing pre-existing stresses is good practice.

Ballast: Avoid having excessive amounts of slack ballast tanks. If ballasting is necessary for stability or stress management in heavy weather, it should be done with careful consideration of free surface effects and induced stresses.

E. Machinery and Steering Gear:

Engine Room Readiness: Ensure main engine, auxiliary engines, and all essential machinery are in good working order. Check lube oil levels, cooling systems, and fuel Purity.

Steering Gear: Test steering gear (main and emergency) and ensure it is fully operational.

Bilge Pumps: Confirm bilge pumps (main and emergency) are ready for immediate use.

F. Crew Briefing and Preparation:

Safety Briefing: Conduct a safety briefing for all crew, outlining the expected weather, precautions taken, assigned duties in case of emergency, and emphasizing personal safety (e.g., use of handholds, avoiding exposed decks).

Rig Lifelines: Rig safety lifelines in exposed walkways on deck if personnel might need to transit these areas (though this should be minimized).

Personal Protective Equipment (PPE): Ensure all crew have access to and use appropriate PPE if required to be on deck (lifejackets, safety harnesses, non-slip footwear).

Meal Preparation: Prepare meals in advance if very heavy weather is expected, to minimize work in the galley during severe rolling/pitching.

Rest: Encourage crew to get adequate rest before the onset of heavy weather.

6. Actions When Heavy Weather is Encountered:

A. Vessel Handling and Seamanship:

Reduce Speed: This is often the most effective single action to reduce stresses on the hull, minimize slamming, and lessen the severity of ship motions. The appropriate speed reduction depends on the vessel, its loading condition, and the sea state.

Alter Course: Adjust course to find the most comfortable heading relative to the wind and waves. This might be:

Heading into the seas (or slightly off): Often reduces rolling but can increase pitching and slamming.

Running with the seas (stern-to or quartering seas): Can reduce pitching and slamming but may lead to heavy rolling, risk of broaching (turning beam-on to the seas), or pooping (waves breaking over the stern). Requires careful steering.

Beam-on to the seas: Generally avoided as it causes the heaviest rolling and is most dangerous for cargo shifting and stability.

Heaving-To: In extreme conditions, it may be necessary to heave-to (maintaining minimal headway with the bow or stern to the weather) to ride out the storm.

Avoid Synchronous Rolling: If the vessel’s natural rolling period coincides with the wave encounter period, very heavy rolling can occur. Altering course or speed can break this synchronicity.

B. Continuous Monitoring:

Vessel’s Motion and Stresses: Pay close attention to how the vessel is behaving. Listen for unusual noises (groaning, cracking) that might indicate structural stress. Be aware of areas prone to slamming or heavy wave impact.

Weather Conditions: Continuously monitor weather reports and observe actual conditions (wind speed/direction, wave height/period/direction).

Steering: Ensure responsive steering. If autopilot is used, monitor it closely and be ready to switch to hand steering if it struggles to maintain course.

Engine Performance: Monitor main engine RPM, temperatures, and pressures.

Water Ingress:

Regularly check bilge soundings in all cargo holds and other compartments.

Visually inspect hatch covers, ventilators, and deck fittings for any signs of leakage or damage (only if safe to do so from a protected position).

Cargo Condition (if possible and safe): Check for any signs of cargo shifting (unexplained list, noises).

Security of Items on Deck and Internally.

C. Crew Safety:

Restrict access to exposed decks.

Ensure personnel moving about the vessel use handholds and exercise extreme caution.

Maintain good communication throughout the ship.

D. Damage Control Preparedness:

Have damage control equipment (e.g., timber shores, wedges, cement boxes, portable pumps) readily available in case of hull breach or serious leaks.

Ensure fire-fighting equipment is ready.

E. Reporting:

Keep the company (DPA) regularly informed of the vessel’s status, weather conditions, and any problems encountered.

Send out appropriate safety messages (e.g., Securité if encountering an unforecasted severe storm that could affect other shipping) or distress messages if the vessel is in grave danger.

7. Post-Heavy Weather Actions:

Thorough Inspection: Once clear of the heavy weather, conduct a comprehensive inspection of the vessel as soon as it is safe to do so:

Hull structure (for cracks, dents, deformation).

Hatch covers, coamings, and securing devices.

Ventilators, air pipes, and other deck fittings.

Anchoring and mooring equipment.

Masts and rigging.

Cargo holds (for water ingress, cargo shift, damage).

Engine room and steering gear compartment.

Damage Assessment and Reporting: Report any damage found to the company, Class society (if it affects seaworthiness), and insurers as appropriate.

Log All Details: Meticulously record the duration and severity of the heavy weather, actions taken, any damage sustained, and results of inspections in the ship’s logbook.

8. Master’s Overriding Authority and Responsibility:

The Master has the ultimate responsibility and overriding authority for all decisions related to navigating the vessel in heavy weather. This includes decisions on course, speed, and when to take evasive action or seek shelter. Commercial pressures must never compromise the safety of the vessel, crew, and cargo.

Prudent Judgment: Relies on experience, good seamanship, and careful interpretation of all available information.

Decisive Action: Must be prepared to make timely and decisive actions to mitigate risks.

Prioritization of Safety: Safety of life is always the highest priority, followed by the safety of the vessel and then the cargo.

Navigating a loaded bulk carrier through heavy weather is a true test of a Master’s skill, preparation, and judgment. By taking comprehensive precautions, exercising prudent seamanship, and maintaining constant vigilance, the risks associated with severe sea conditions can be significantly mitigated, ensuring the vessel and its valuable cargo complete their voyage safely.