Thursday, May 3, 2012



The STS transfer of chemical cargoes is a common practice.  Experience gained from these regular operations has proven that STS  transfers are safe, if proper procedures are observed, in suitable weather and sea conditions.

In certain port areas it will be  found that local regulations apply. These local regulations should be followed  and where appropriate the recommendations made in this procedure can be  used as additional advice. 


The overall control of an STS operation should be vested in the hands of one  individual and will be either one of the Masters concerned, or an STS  superintendent.  

If both Masters are unfamiliar with, or inexperienced in STS transfer operations then an STS superintendent must be employed to assist ship’s  masters in mooring and unmooring of the ships, and to co-ordinate and  supervise the entire ship-to-ship operation. There are specialised  STS  agencies providing such services on an international basis.

Master of the ship supposed to be involved in STS transfer operation has to inform the chemical operator in order to arrange necessary assistance. Master must satisfy himself that acceptable conditions for Ship to Ship (STS) transfer exist.

There must be sufficient resilience in the moorings to absorb the movement between vessels

For all STS transfer operation Master remain responsible for the safety of his  own ship, its crew, cargo and equipment and should not permit safety to be  prejudiced by the actions of others. If another ship fails to observe any of the  safety requirements during the STS transfer operation, this should be brought  to the attention of the Master of the another ship and operation should be  suspended until the situation is rectified. To protect both vessels from damage, fenders must be of sufficient size and strength, and be strategically placed, so as to:

1.absorb the impact energy during berthing/unberthing

2.maintain adequate separation between ships allowing for normal movement and listing.


Master of the ship involved in STS transfer operation should ensure that the  ships to be used are compatible in design and equipment and that mooring  operations, hose handling and communications can be conducted safely and  efficiently. The initial information will be supplied to the organisers  by the  Master as per Check List 1 ( ICS / OCIMF  SHIP TO SHIP TRANSFER  GUIDE ). 

Additionally to Check List 1, the following should be determined prior to  mooring:

whether approval from local authorities have been received

the size and number of manifolds to be used

whether the cargo cranes or derricks are in satisfactory condition 

whose hoses will be in use and last pressure test of the hoses

which ship ( mother-ship or daughter-ship ) has Yokohama fenders 

STS On arrival at the terminal, ships must confirm with the terminal, the wind speed restrictions applicable to the terminal or berth i.e.:

--The maximum wind speed at which the cargo is to be stopped.

--The maximum wind speed at which the cargo hoses are to be disconnected.

--The maximum wind speed at which the own ship is to cast off.

The above wind speed restrictions are to be notated in the ISGOTT Ship / Shore Checklist.

Good communication between the ships is an essential requirement for  successful transfer operations. A common language for communication should  be agreed before operations commence. If a serious language problem be  detected, then action should be taken  to resolve this by transferring  an  experienced person from one ship to the other before operations begin.

The ships should establish initial communication as early as practicable to  plan operations and to confirm the transfer area.

As the ships come into the transfer area, contact should be established on the  appropriate VHF channel at the earliest opportunity, thereafter switching to a  mutually agreed working channel. Approach, mooring and unmooring should  not be attempted until proper effective communication has been confirmed  between two ships. At this time, in accordance with the information  exchanged, Check List 2 and 3 should be satisfactory completed.

If communication breakdown occurs during an approach manoeuvre, if  appropriate and safe, the manoeuvre should be aborted and the subsequent  actions taken by each ship should be indicated by the appropriate sound  signals as prescribed in the  IRPCS (colreg).

During cargo transfer operation, essential personnel on both ships should  have a reliable, common means of communication at all times, including a backup system. Spare radios and batteries to be available on board.

The emergency signal should be agreed between both ships and this should  be a series of short and rapid blasts on the ship whistle. It should be sounded  by either ship in an emergency or in case of communication breakdown during  cargo operations.

In general, operations should not be resumed until satisfactory  communications have been re-established.

The lights and shapes to be shown, and the sound signal made, during STS  transfer operations required by the  International Regulations for Preventing  Collisions at Sea.


One ship, normally the lager, maintain steerage way at slow speed on a  constant heading. Normally the manoeuvre should be made with the wind   and sea ahead, however local conditions and knowledge may dictate an  alternative heading.  It is recommended that the manoeuvring ship  approaches and berths with her port side to the starboard side of the constant  heading ship. The Master should always be prepared to abort a berthing  operations if necessary. The decision should be taken in ample time while the  situation is still under control.

A common method of berthing is for the manoeuvring ship to approach the  constant heading ship from the quarter on the side of berthing. On closer  approach she should parallel the course of the constant heading ship, about  50 to 100 meters off. The manoeuvring ship should then position itself relative  to the constant heading ship. Contact is made by the manoeuvring ship  reducing the distance by appropriate rudder and engine movements until  fenders touch.

The two ships should preferably make parallel contact at the same speed with  no astern engine movements being necessary.

The effects of ship interaction should be anticipated when manoeuvring at  close quarters.

On completion of mooring, the constant heading ship will power all future  manoeuvres and, if a transfer at anchor is planned, will proceed to the agreed  anchoring position. During this time the former manoeuvring ship will have its  engines stopped and rudder amidships. For this period the constant heading  ship should not use strong astern engine movements.

Depends upon ships size and weather condition it should be decided whether  only constant heading ship will anchor or both ship. The constant heading  ship should use the anchor on the side opposite that on witch the other ship is  moored.

Once at anchor, each ship is responsible for keeping its own anchor watch.


This manoeuvre can be preferred for more constrained transfer area,  especially when tug assistance is available.

A berthing operation should only be carried out after the anchoring ship is  brought-up to her anchor and is lying on a steady heading with reference to  prevailing current and wind conditions.

A careful watch should be kept on the heading of the anchored ship and the  manoeuvring ship should be advised immediately by the anchored ship if she  has any tendency to yaw. Where there is a tendency to yaw is excessively, a  tug should be employed to hold the anchored ship on a steady heading. If no  tug is available, postponement of the operation should be considered.

The manoeuvring ship approach and berth with  her port side to the starboard  side of the other ship. When approaching the ship at anchor the wider angle  of approach than that adopted for manoeuvres underway is recommended. A  wider angle of approach helps to avoid early ship to ship contact in cases  where the anchored ship might yaw unexpectedly.  

When mooring to an anchored vessel care should be taken not to pull the  anchored vessel quickly towards the mooring vessel. 


When two ships are securely moored the pre-transfer Check List 4 should be  satisfactory completed. In addition, Ship/Shore Safety Check List to be  completed as well.

Cargo transfer operations should be carried with the requirements of the  receiving ship.

The cargo transfer operation should be planned and agreed in written  between the two vessels and should include information on the following  where applicable:

quantity of each grade of cargo

sequence of grade

cargo density and temperature

number of pumps, maximum pressure

cargo heating requirements

initial, maximum and topping off rate

notice of rate change and transfer shut down procedures

emergency and spill containment procedures

watch or shift arrangements

critical stage of the operation

The agreed transfer rate should not exceed the manufacturers recommended  flow rate for the cargo hoses.

Electrical bonding between the vessels hulls is not necessary.

Throughout cargo transfer operations, the both ships should station  a  responsible person at the cargo manifold area to observe the hoses and to  check for leaks. A responsible person equipped with portable radio should be  stationed at or near the cargo pump controls on the discharging ship to take  action as required.

Cargo transfer should begin at agreed slow rate to enable the receiving ship  to check that the cargo pipelines system is correct set.

It should be noted that the incorrect operations of pumps and valves can  produce pressure surges in a pipeline system. Consideration should be given  to the prevention of pressure surges by careful planning and control of pump  speeds and the operation of valves.

During cargo transfer, appropriate ballast operations should be performed in  order to minimise change in freeboard, and avoid excessive trim by the stern.

Throughout the transfer, regular hourly transfer rate checks and comparisons  should be made between the two vessels, and the results logged.

The transfer rate should be reduced to an agreed topping off rate when the  receiving ship’s tanks  are reaching their feeling limit.

After completion of cargo transfer the following operations should be carried  out:

All hoses drained into one ship prior to disconnecting

Hoses disconnected, taking precautions to ensure that no liquid is left in the  cargo transfer system

Cargo manifolds and cargo hoses securely blanked

Authorities informed of completion of cargo transfer and anticipated time of  unmooring



Check list 5 to be completed before unmooring.

Unmooring can be achieved  by singling up fore and aft, then letting go the remaining forward mooring and  allowing the bow to swing away from the constant heading ship to the suitable  angle, at which time the remaining stern mooring line is let to go and the  manoeuvring ship moves clear. After disengaging, neither ship should attempt to steam ahead or fall astern of the  other until both ships are well separated. 

It should be noted that local conditions or vessel configuration may cause  difficulties in separating the two ships and other alternative plans should be  considered. 




Is the parallel body length suitable for loaded/ ballast drafts?

Is the freeboard suitable while coming alongside?

Considering chemical tankers freeboards are low are height of fixed fenders suitable?

If fixed fenders will crush railings are Yokohama fenders available?

If the STS is planned underway can the ship maintain 5 knots for 2 hours minimum?

Are  the ships lifting gear suitable for the operation?

Do both vessels have sufficient enclosed fairleads to prevent damage to railings?

Are the fairleads suitable for providing spring ropes?

If the mooring ropes are wires are there proper synthetic tails?

Is the vessel clear of any overhanging projections?

Is the weather suitable?

Do you have sufficient weighted heaving lines ?

Are the mooring ropes being used floating on water?

Has the transfer area and rendezvous area been agreed upon?

Is there a basket for transporting personnel?

Have methods of communication been agreed upon?

Is sufficient crew available to handle mooring lines?

Has the language of communications been agreed upon?

Has it been agreed which ship will send which lines and in what sequence?

Will both the ships be upright?

Will the ships have suitable trim?

Has the weather forecast been obtained?

Are the STS transfer hoses in good condition?

Do the fender ropes appear to be in good condition?

Has a crew meeting been held?

Is there a contingency plan and has it been agreed ?

Are appropriate local authorities briefed of the operation?

Has a navigation warning been issued?

Are proper signals displayed?

Are portable fenders available on the agreed side alongside?


Have flags been put at the manifold?

Is there somebody at the manifold to position the vessel ahead / astern ?

Are secondary emergency prtable light fenders available?

Are the cargo manifold connections ready and marked?

For underway operations has the course and speed info been exchanged and understood?

Is lighting adequate at night?

Have the mooring winches been tried out in advance?

Are proper rope stoppers in place?

Are anchors ready for immediate use?

Is the course recorder on?

If the mother ships is at anchor is her yaw being monitored and reported ?

Is there a qualified and proficient helmsman available?

Is the wind and tide direction/ strength being monitored?


Have the cargo hoses been drained prior disconnection?

Are all the hoses and manifolds blanked?

Is the space between the ships clear of obstruction?

Has the sequence of unmooring been agreed upon?

Is the position of fenders suitable for the unmooring method?

Have the mooring winches been tried out?

Is crew standby at mooring stations?

Has internal / external communications been tried out?

Has local shipping movement been checked?

Have the local authorities been notified?

Note: In case of negative answer pl give brief reason if relevent


The lightering vessel, or support tug  shall make a navigational warning prior to the commencement of lightening operations via VHF.  If the situation warrants (poor visibility, high traffic density, vessels drifting or slow steaming, etc.), voice warning must be made at frequent intervals.

Operations must be carried out in a safe manner and oil pollution must be avoided. these items have first consideration over all other factors, and all the personnel onboard shall be made aware of this.

The vessel will, at all times, be capable of immediate manoeuvres while engaged in the lightering operations. The main plant must not be immobilized at any time.

The vessel should conduct “break away drills”  prior to arrival to ensure that officers and crew are fully aware of their stations and duties in a lightering operation emergency.

If the operation is carried out underway, full bridge and engine room watches are to be maintained on throughout the operation.  During still air conditions, a watch must be kept for lightning and thunder. STS loading/ unloading operations must stop immediately in such a scenario.  Do NOT under estimate the danger posed by lightning.


Individual vessels may have lower loading rate capability than the hoses, and the cargo transfer rate should be set accordingly. Loading/discharge rates and manifold pressures are to be monitored to ensure that the permitted rates are never exceeded.

In case oil escapes into the water, all cargo operations shall be stopped immediately, the local authorities and the agent shall be notified and the Vessel Response Plan or SOPEP activated as applicable.

Prior to mooring, vessel should blow soot from boilers. During operations when ships are moored together, tubes should not be blown.

Transfer of personnel between ships should be conducted with the approval of the Masters and Lightering Master. Those personnel engaging in transfer between the vessels (this includes the lightering support craft in attendance) shall wear appropriate PPE and use an approved transfer basket (e.g.: Billy Pugh type). Steadying lines shall be used to prevent the basket swinging.

STS During ship-to-ship operations, consideration must be given to restricting the use of radars if the relative freeboards between the two ships might expose the personnel working on deck to electro-magnetic radiation from the radar scanners.

When transferring cargo to or from barges it is essential that there is no relaxation of normal safety precautions and procedures. When conducting operations with barges due consideration should be given to the possibility that the barge procedures may be significantly different to those used onboard the ship. It may also be the case that the barge personnel are not experienced seafarers or tankermen. Extra vigilance by the ship's staff may therefore be necessary to prevent an incident. If communication between ship and barge is lost for any reason, the transfer operation must be stopped immediately. Operations must not be resumed until communications have been re-established.



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