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Problem with helicopter operations on gas carriers & other deck precautions
Gas carriers are recommended not to undertake routine helicopter operations unless a purpose-built helicopter platform is provided. Whenever helicopter services are used the safety measures recommended in the ICS “Guide to Helicopter / Ship Operations” should be taken into account.
Types of operating areas
Ships operating areas fall into two distinct types:
a) Landing Area – defined as an operating area suitable for landing helicopters. The landing
area may consist of a purpose built structure located above the ship’s deck located on or
over the stern of the ship. A landing area may also be used for winching operations.
b) Winching Area – defined as an operating area which may only be used for winching
The potential hazards associated with helicopter operations involving LNG vessels must be clearly
recognised by all concerned. Before any helicopter operations are allowed to take place permission
must be obtained from the Managing Office.
The major problem with helicopter operations on gas carriers is the lack of clear space available for
an operating area, coupled with the high risk of damage to the deck installations and the difficulty
in controlling any resulting fire. As most gas carriers are unable to provide a suitable clear space in
the cargo area or on the forecastle for helicopter operations, the only suitable and safe place
where operations may be carried out is on the poop deck.
This area has advantages for helicopter operations due to its remoteness from the cargo tank area,
but it has some disadvantages.
- The lack of clear deck space because of mooring equipment
- The requirement to protect the accommodation against the potential hazards of a
- Problems such as excessive pitch, roll and heave
- Turbulent air flow above the accommodation block and funnel which may make control of
the helicopter difficult.
The ideal solution is for the gas carrier to have a purpose built platform, specially designed to
alleviate the problems (a) and (b) above. It may also be helpful, if the ship is manoeuvered so that
the wind is within 35 degrees of the beam, preferably on the port side, although final instructions
and requests regarding this will be given by the helicopter pilot prior to final approach. On receipt
of this advice, the Master must consider the request having due regard to his obligations for safe
navigation and collision avoidance. If the Master is unable to comply fully with these obligations for
safe navigation and collision avoidance, then this fact must be communicated to the helicopter pilot
and operations delayed until the Master is able to comply with these obligations.
It is recommended that routine helicopter operations should not take place unless a platform is
provided. Winching operations at a designated winching area away from the poop deck, may
however be permitted on occasions, and a full Risk Assessment must be carried out before the
permission is given for the operation to proceed.
Vapour emission control
The venting of cargo vapours to atmosphere under normal operating conditions should not occur,
unless there has been some malfunction or mal-operation of the cargo system. The only possible
sources of vapour on deck should therefore be minor, such as leakage from valve glands, pipeline
joints or improperly seated pressure relief valves.
In order to eliminate any possibility of a major escape of vapour during helicopter operations due
to the lifting of safety valves, cargo tank pressures should be reduced prior to the arrival of the
helicopter. However due to the design function and safety procedures inherent in the gas burning
system, there is no requirement for these operations to be suspended during helicopter operations.
All tank lids and other openings must be closed securely to restrict the effects of any accident.
General deck precautions for Gas carriers at sea
To avoid an over reliance on computerised alarms systems, it is important that daily rounds of the
cargo deck and compressor house are carried out. Areas which should be particularly sighted on
these rounds are;
- bellows pieces, as deformation of the bellows is an indication of excess pressure in the
- readings on local temperature and pressure gauges on vapour and liquid lines, to
ensure that the readings given are as expected at that stage of the voyage,
- Areas of un-insulated pipework for any unexpected ice build up, particularly on the
- Any movement of the liquid and vapour lines through the sliding feet, noting direction
and amount of movement,
- Any signs of leakages from valves, vents and flanges,
- Overall condition of the cargo system
Any anomalies or unexpected observations are to be investigated, and where necessary corrective
action taken. The managing office should be informed of any observed problems.
An entry should be made in the deck log Book when deck rounds have been completed,
along with the results of the inspection. Any deficiencies or unexpected conditions must be
recorded, along with an entry when corrective action has been taken.
Lashing of Movable Articles
Articles that are likely to generate sparks, such as iron, aluminum or other light metal articles, shall be secured or stored in preparation for rolling of the vessel.
The Scupper Plug
The scuppers should be effectively plugged and condition of scupper plugs should be satisfactory. Scuppers on gas carriers will only be required to be plugged when bunkering or if carrying a MARPOL Annex 1 cargo.
Indicating Regulation Signals
While the vessel carrying dangerous cargo shall exhibit a ‘B’ flag in the daytime and a red light in the night time where they can best be seen. And even outside the port, exhibit the signals stipulated in the Marine Traffic Safety Law both while being navigating and while being moored in waters where the Marine Traffic Safety Law is applicable (Japan).
More safety precautions and instructions for liquefied gas carrier :
Mooring requirements for gas carrier
Means of access to ship
Standards for use of Mobile-phone
Precautions against abnormal weather
Dispersal of vented cargo vapours
Openings in deckhouses
Engine room precautions
Cargo machinery room precautions
Ship’s readiness to move
Drying of Cargo Tanks and preparation for loading LNG cargo
- Cargo Information - physical and chemical properties necessary for the safe containment of the cargo
- LNG spill risk during marine transportation and hazards associated
- How to tackle fire on board LNG ship
- Displacing with Vapour of the Next Cargo (Purging)
- Fire fighting plan for LNG cargo
Inerting of Cargo Tanks prior loading LNG cargo
Initial Cool Down of cargo tanks
Gas cargo containment systems - primary barrier (the cargo tank),secondary barrier, thermal insulation and more
Preparatory operations of drydocking for LNG carriers
Procedure for transporting remote gas
Development and potential of todays emerging gas technologies
Transporting economically viable compressed gas liquids from remote fields
The risk of laden voyage - a brief guide to liquefied gas carriers
Connection and disconnection of cargo hoses and hard arms
The risk of ballast voyage - a brief guide to liquefied gas carriers
The risk of laden voyage - a brief guide to liquefied gas carriers
Liquefied gases - Health hazards
Liquefied gas cargo reactivity
Liquefied gas cargo corrosion
Liquefied gas cargo vapour characteristics
Liquefied gas cargo - low temperature effects
Liquefied gas carrier -monitoring cargo pressure
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