Heavy Weather Preparations & Checklist

Heavy Weather Preparations & Checklist - MASCOTMARITIME

Table of Contents

What is heavy weather?

In shipping, the term “heavy weather” is defined as a combination of strong winds of Beaufort wind scale 7 (Douglas scale 6) or more and waves with a height of 4 meters or more.


The Master to ensure due diligence and precaution are taken by vessels scheduled to make trans-North Atlantic/ North Pacific voyages, or when vessels are in the vicinity of a tropical depression/cyclone.

Ships that are scheduled to make trans-Atlantic or transpacific voyages in the bad weather periods, mainly during the winter months may request weather routing information from the charterers in consultation with vessel owners.

Also, every Master should be guided by instructions provided in the Manuals/checklist provided by the company for heavy weather.

During the time of the year when winter sets in the Northern hemisphere and mariners expect heavy weather and cold wintry conditions.

Below information /checklist is to help prepare the vessels to avoid any injuries to personnel and damages to property:

Personnel (Master, crew, passengers)

All personnel must wear proper winter gear and be careful of trips/ falls in icy deck conditions. If the situation demands, the seafarers going out to check/secure loose items on deck or under deck should only be doing it in daylight, with the vessel course adjusted to minimize rolling and/or pitching.


  1. Deck hydraulic machinery: Machinery must be warmed up well in advance before the actual operation. Oil temperature to be monitored.
  2. Check whether the bridge window pane heater is operational.
  3. Fire lines on deck, anchor wash lines: Are the lines drained?
  4. Emergency generator: Check if antifreeze is in the water in the cooling jacket/radiator. It should never freeze. The room heater should be on.
  5. Air conditioning plant heating: Is it in good working condition?
  6. Cooling water recirculating valve: Is the o/b recirculating valve operational?
  7. Sea chest – steam blow lines: are they functional?

Check out top curated weather links for quick reference.

For vessels trading in the North Atlantic and North Pacific areas the need for extra precautions when preparing your vessel for sea, en-route, and in port is extremely important. 


  1. Always ensure that the vessel has sufficient bunker reserves for the passage taking into account the adverse heavy weather conditions. Seek advice or assistance from the Manager or Owner(s)/Charterer(s) office if you have any concerns or doubts in this regard.
  2. Ensure that all loose material in all stores and deck are well secured (heavy engine spares to be wedged by welded angle bars on deck + lashing).
  3. All watertight doors, Foc’sle store booby hatches to be well secured, and additional lashing from inside to be taken. Bilges’ high water level alarms to be tested periodically and bilge pumping /educting to be proved. All vent flaps on the forecastle and doors at break of forecastle (for stores etc.) are properly shut and secured (with no gaps in rubber packing) with no chance of dogs becoming loose. Secure the Suez Canal light receptacle box. Hold access booby hatch covers properly secured with all butterfly nuts.
  1. (i) Ensure anchors are well housed and secured with additional lashings as required. It is a good idea to lash the horizontal Guillotine bar’s mid-section to the anchor chain near the hawse pipe so that if the chain runs the bar is pulled tighter. Anchor’s Spurling pipes to be covered and cemented. Make lugs inside the chain locker so that the free length of chain going into the chain locker can be lashed inside the chain locker by synthetic rope. This way chain movement is restricted and does not break the cement. Chain locker hatches and bitter end pin glands to be tight so that accidental filling of chain locker does not flood the foc’sle store. It is a good idea to ease the bitter end and ensure that it can in fact be slipped/knocked out in an emergency. (ii) The cautions about the hydraulic system for windlass and ensuring that it can be hydraulically isolated from other systems to be reviewed and measures put in place. For both hydraulic and steam systems, ensure no leaks which can reduce heaving power.(iii) Strong winds while alongside demand special care of moorings and strengthened mooring watches, doubling of moorings, and call tugs to assist the vessel to stay alongside well in time. Review safety of cargo operations in strong wind conditions.
  2. Gangways lashing to be tightened regularly as a loose wire or rigid lashings leave room for movement and subsequently get damaged when seas are shipped on deck. The present securing arrangements to be reviewed and enhanced as required.
  3. Ensure all precautions for cargo security are taken such as lashings, shoring/tomming, airbags, tight stow, etc. This applies equally to on-deck and under-deck cargo including timber cargo. Check security and stability of walkways on timber cargoes.
  4. Anyone going on deck in Heavy weather must do so in teams of two or more and stay on lee side with the possibility to take shelter, or on a tether line. Safety briefing to be done prior to going on deck or before man entry in cargo spaces for checking lashings. Always carry Walkie Talkies covered in water protective cling wrap and stay in touch with OOW on the bridge.
  5. Ensure that caps on ballast/hold bilge sounding pipes/ temperature pipes are firmly closed and no chance of caps getting washed away resulting in water ingress. Check & confirm all hydraulic valve boxes on the main deck are properly secured. Non-return valves on hatch drain channels are clear of debris and working in non-return mode. Engine room double bottom tank sounding pipes caps tight, and spring type cock in closed position.
  6. On Bulk Carriers, correct ventilation of holds to be followed and vents trimmed or closed in heavy weather.
  7. Engine rpm is to be reduced to a manageable load and avoid slamming whenever necessary, in consultation with C/E. A decision to heave to and await the passing of the worst weather may also be taken, when it becomes obvious there is nothing to be gained by steaming against adverse winds/seas.
  8. Container and PCC vessels to avoid heavy rolling (parametric rolling) by judicious course and speed adjustments made well in time. Ballast exchange requirements in these vessels especially and in all vessels in general are to be complied with only in calm to moderate weather. Pay attention to proper procedure and soundings being taken to ensure sufficient stability and positive GM. On Bulk carriers Heavy weather ballast holds should be prepared for ballast first when cleaning holds in port and any heavy weather ballast required to be taken in holds should be taken while still in port and before putting out to sea. Do not wait till heavy weather strikes to take hold ballast for damage due to slamming can easily occur.  At sea slamming danger in Heavy weather, ballast hold must be recognised and hold kept topped up with hoses if overflowing. Ensure Hold ventilators are opened before ballasting/deballasting holds, as many bulkers hatch pontoons have been damaged due to negligence in this respect.
  9. Ensure lube oil sump levels for both the m/e and a/e’s are maintained at a level to avoid pumps losing suction.
  10. Ensure the seawater pumps are set to low suction to avoid losing suction during heavy pitching of vessels.
  11. Ensure that the Engine room crane and the hook are secured at one end to avoid accidental movement and possible damage to property and personnel.
  12. Ensure the items in the provision stores and cold rooms are secured properly.
  13. Ensure the cook & catering staff understand the dangers involved in cooking during rough weather and using restraining bars on the cooking range. Avoid using large amounts of oil or deep frying during such periods. The oil level in the pan is low.
  14. Anchoring in areas exposed to rough weather: If any doubts exist as to the safety of the designated anchorage area (eg. proximity to land, quality of holding ground, protection from the weather, traffic density within anchorage, etc.), it is the Master’s responsibility to take any action considered necessary for his vessel’s safety. If this involves moving further out to sea & drifting/remaining hove too with engines working / in readiness, such a decision would be fully acceptable. 

If in doubt, Master should discuss the merits of the case with the marine safety & insurance department of his company. It is advisable for ships to heave up anchor and proceed to sea and hove too well in time once sustained wind gets to say above 30 knots than to wait till it worsens. It is better to go to sea and be hove to than to try and use TWO anchors instead of one and try to stay in port.

  1. The RoRo, PCC, and Container vessels to review now High wind effects for maneuvering and when alongside in line with guidelines given by Owners/operators & managers, check mooring requirements and ropes condition. 
  2. If forced to be at anchor or alongside or liable to drift on to shore in high wind conditions it is a good idea to ballast the ship down as much as possible before the onset of heavy weather, so that even if you do run aground then the vessel has a chance to deballast and refloat the vessel quickly.
  3. On-board cold weather procedures & precautions to be reviewed and ensure strict compliance for crew & operational safety. If going to a severe winter area, ensure staff has proper severe winter gear beforehand.
  4. Secure accommodation doors by using hooks or other strong means when open. Every year many crush injuries have occurred by swinging doors.
  5. On receiving a heavy weather advisory, the Master should call for a safety meeting and brief all crew.

At present days there are usually warnings about the development of a hurricane/cyclone/typhoon or other serious weather phenomena. This information is usually available many days before the weather arrives. The key is how this information is being used and what preventive measures are being taken.

Nowadays many marine weather forecast sites are available, and mariners should make the best use of these.


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