| CTM 9.11 |
Chemical Tanker Manual CTM Ship to Ship Transfer of Annex II Cargoes |
Doc No.: CTM 9.11
Revision: 01 Date: 15 Oct 2024 Issued by: DPA Approved by: MD |
1 APPLICATION
This document applies to all Chemical Tankers managed by Company.
2 PURPOSE
The purpose of this document is to specify requirements for ship-to-ship transfer of Annex II Cargoes.
3 RESPONSIBILITIES
- Master shall:
- Ensure STS operation is carried out in accordance with reference documents listed in Section 4.
- Seek Marine Department approval prior to STS operation.
- Notify relevant authorities.
- Liaise with STS superintendent/mooring master (Person in Overall Advisory Control – POAC).
- Chief officer shall:
- Coordinate with Master for mooring operation.
- Prepare cargo plan.
- Comply with STS transfer checklists.
- Deck officers shall:
- Assist Master & Chief Officer during STS operation as directed.
4 REFERENCES
Master/Officers involved in STS operations shall refer and familiarize themselves with STS procedures as stated in:
- OCIMF/ICS STS Transfer Guide
- Ship’s approved STS plan
- Tanker Safety Guide (TSG) for chemicals
5 OFFICE CONCURRENCE
Note:
- Master shall seek written concurrence from Marine Superintendent/ Marine Department prior STS operation for safety and insurance purpose.
Master shall submit the following for approval:
Information:
- Expected date of STS operation.
- Location & name of vessel(s) for STS operation.
- Details of cargo.
- Details of instructions from operators.
Documents:
- Q88 of vessel(s) in question.
- STS Form 01- Ship to Ship Transfer Questionnaire
- Risk assessment - considering the following aspects:
- Lightering area
- Current condition
- Traffic density
- Tugs & Mooring master availability
- Contingency Anchorage
- Bridge watch condition
- Primary & secondary fenders
- STS service provider
- Transfer at anchor or underway
6 STAGES OF STS OPERATIONS
Coution:
- STS berthing during hours of darkness is prohibited, unless approved by Senior management.
Stage 1- Prior arrival:
- Ensure STS Form 01A - STS “Pre-Fixture information” completed by ship operators & managers.
Stage 2- Arrival:
- Ensure compliance with STS Form 01B - STS “Before operations commence”.
Stage 3- Berthing:
- Ensure compliance with STS Form 01C - STS “Before run in and mooring”.
- Ensure contingency plan in place.
Stage 4- Cargo Transfer:
- Ensure compliance with STS Form 01D - STS “Before Cargo Transfer”.
Stage 5- Departure:
- Ensure compliance with STS Form 01E - STS “Before Unmooring”.
Coution:
- Abandon STS operation at any stage in case of safety concerns.
For Personal transfer refer to STS Form 01F - STS Personal Transfer by Crane. For vapour balancing refer to STS Form 01G - STS Involving Vapour Balancing.
7 VAPOUR BALANCING CONSIDERATIONS
- Vapor balancing may be required by local regulations during STS transfer of hazardous cargo.
- Reference for operational requirements:
- 46 CFR 39 – Vapour Control Systems
- ISGOTT 11.9.3, 7.1.6.4
- Master shall ensure cargo operations for flammable cargoes are conducted under closed conditions with ullage, sounding, and sampling ports securely closed.
Note:
- Give due regard to any local regulations that may require the adoption of special vapour balancing procedures.
Vapour balancing considerations before commencing cargo transfer
Note:
- Equipment shall be provided on at least one of the vessels to enable the oxygen content of the vapour stream to be monitored.
Officer in charge shall:
- Test the oxygen analyser and associated alarms prior to each operation.
- Check and confirm the oxygen content of the vapour space of each tank connected to the IG main to be less than 8% by volume.
- Seek confirmation of above point from the officer in charge of the other ship as well.
- Ensure the vapour transfer hose is purged of air and inerted prior to commencing transfer of vapours.
Note:
- The vapour manifold valves may not be opened until the pressure in the cargo system of the receiving vessel exceeds that of the ship discharging cargo.
7.2 Vapour balancing considerations during cargo transfer
Officer in charge shall consider the following points:
- The oxygen analyser shall draw samples continuously from a location close to the vapour manifold connection.
- Above system shall include the facility for audible and visual alarms:
- If the oxygen content of the vapour stream exceeds 8% by volume.
- The inert gas (N2) system on the discharging ship shall be:
- Kept operational and
- On standby, with the inert gas main deck isolating valve closed.
- Used if inert gas pressure in discharging vessel falls to low level (300 mm WG).
- The inert gas pressure on both ships shall be monitored and each ship advised of the other’s pressure on a regular basis.
Coution:
- No air shall be allowed to enter the cargo tanks of the discharging ship.
Transfer operations shall be suspended if the oxygen content of the vapour stream exceeds 8 % by volume, and
may only be resumed once the oxygen content has been reduced to 8% or less by volume.
Coution:
- The cargo transfer rate must not exceed the design rate for the vapour balancing hose.
8 FORMS
- STS Form 01 - Ship to Ship Transfer Questionnaire
- STS Form 01A - STS Pre-Fixture information
- STS Form 01B - STS Before operations commence
- STS Form 01C - STS Before run in and mooring
- STS Form 01D - STS Before Cargo Transfer
- STS Form 01E - STS Before Unmooring
- STS Form 01F - STS Personal Transfer by Crane
- STS Form 01G - STS Involving Vapour Balancing