SUPPLY OPERATION WITH "TIED UP TO THE RIG" MODE

MANEUVER TIED UP TO THE RIG 

Dear all Seafarers,

Supply operations bagi kapal AHTS adalah merupakan kegiatan rutin yang tidak terhindarkan, bagi kapal2 NON DP VESSEL maka supply operation ini hanya bisa dilakukan dengan dua cara yaitu “Snatching dan Tied up to the RIG” Berikut saya akan membahas tentang bagimana sih caranya “Tied up to the Rig”itu. Article berikut ini saya ambil berdasarkan pengalaman pribadi saya yang tentu saja banyak kekurangan didalamnya, untuk itu jika ada kritik atau saran atas kesalahan dari article ini, dengan senang hati saya akan menerima dan memperbaikinya. Sengaja saya sampaikan dalam bahasa inggris sesederhana mungkin sesuai dg kemampuan bahasa inggris yg pas2an dengan maksud agar article ini bisa bermanfaat bagi semua pelaut diseluruh dunia,.
Bagi saya ketika berbicara tentang dunia pelaut maka kita harus berbicara secara international tanpa memandang suku/Negara pelaut itu berasal. Di laut/kapal kita semua bersaudara, sama2 survive untuk mencarai rezeki dilaut dan sekaligus menjadi Teamwork yg baik dikapal dan ini bisa terlaksana dengan baik jika kita menghilangkan sekat2 kesukuan. Baiklah tanpa memperpanjang pembahasan tentang dunia pelaut yg tidak akan habis dibahas, saya akan langsung saja dengan pokok pembahasan sebagai berikut. 

VESSELS APPROACHING THE RIG PLATFORM.

Every user/charterer has a specific instruction for entering/approaching “500M Safety Zone of the Rig/Offshore Installation” and there is no any big difference of instructions for all offshore area. 

PROCEDURE FOR ENTERING 500M SAFETY ZONE OF THE RIG/OFFSHORE INSTALLATION.

The below are main instruction/procedures prior entering/approaching “500M Safety Zone of the Rig/Offshore Installation”:

1. The Vessel must obtain prior permission from the Rig Coordinators before approaching any Offshore Rig/Barge/Installation.
2. Prior to entering the 500 meter Safety Zone of any Offshore Rig/Installation, the Vessel will complete the checklist (500 M Zone Check List).
3. The Vessel will report to the Rig/Barge/Installation the following message. ‘500meter Safety Zone Check List Completed and request permission for entering 500M safety Zone’ (This communication proves communications between the Vessel and the Rig have been established).
4. Using of ‘Auto Pilot’ is prohibited within the 500 meter Safety Zone.
5. The Vessel must proceed at a Safe Speed within the 500 meter Safety Zone, but must not exceed 3.0 knots (Standard Aramco requirements).
6. No “HEAD-ON” or “DIRECT COURSE” to approach/entry “500 meter Safety Zone of the Rig”, This is for your safety to avoid any collision with rig in case of Power failure.
7. Refer and comply with MOPO (Manual Operating Procedure), This is such a guidelines from charterer for minimum requirement to carried out any operation. 
8. You have to ascertain wind and tide effect on the Vessel at that location by all means and you may STOP the Vessel in the water at a ‘Safe’ distance from the Rig for this purpose.

How to tie up to the Rig and utilize the anchor.

Prior approaching the Rig for tied up always double check on the chart if any pipe/cable lines on the close proximity around the Rig to obtain anchor restriction on this location and seeking such information from Rig radio room.

1. Tied up on the Port side of the Rig:

• Drop anchor position at True bearing = Rig Heading – 60 or 65 Degrees (True bearing from the Rig for anchor position).
• Distance = 0.14 NM – 0.19 NM from the Rig (Depend on water depth, Existing of pipelines/cable at Rig location and seabed anchor holding condition), with this distance your final anchor utilized will be at about 7-11 shackle.
• Example:
• Rig Heading = 330 Degrees. True bearing for anchor position = 330 – 65 = 265 Degrees.
• You may drop your anchor on the position: True bearing 265 Degrees with a distance between 0.14 NM – 0.19 NM from the Rig.
• See the below picture:
  

• This true bearing will become your true heading once all mooring line and anchor secured to the Rig.
• Which Mooring rope to be installed / utilized first:
• “Prior entering 500M Zone of the Rig for Tie up, you have to ascertain the Current direction by all means (There are a lot of methods to determine current direction). This is very importance to decide which mooring rope first to be installed for easy maneuver and the rig always asking about this once you got permission entering 500M Zone for tie up.
• If the current direction going towards “Bow of the rig”, you have to request for tied up with Stern line first. Once “stern line of the rig” already secured tied up to the “Port side (Stern) bollard of the vessel” This line will hold the vessel position from drifting towards bow of the rig due to blowing current direction and easy maneuver to install “Rig bow line” without using more vessel propulsion system.
• If the current direction going towards “Stern of the rig”, you have to request for tied up with Bow line first. Once “Bow line of the rig” already secured tied up to the “Starboard side (Stern) bollard of the vessel” This line will hold the vessel position from drifting towards stern of the rig due to blowing current direction and easy maneuver to install “Rig stern line” without using more vessel propulsion system.

• Once all lines properly secured to the rig, the anchor holding test to be done prior stop the Engine (Heave up anchor with maximum winch power until all mooring line and anchor chain are tied and unable to pick up).

2. Tied up on the starboard side of the Rig:

• Drop anchor position at True bearing = Rig heading + 60 or 65 Degrees (True bearing from the Rig for anchor position).
• Distance = 0.14 NM – 0.19 NM from the Rig (Depend on water depth and seabed holding condition), with this distance your final anchor utilized will be at about 7-11 shackle.
• Example:
• Rig Heading = 330 Degrees. True bearing for anchor position = 330 + 65 = 395 – 360 = 035 Degrees.
• You may drop your anchor on the position: True bearing 035 Degrees with a distance between 0.14 NM – 0.19 NM from the Rig (Depend on water depth, existing of pipelines/cables on the Rig location and seabed anchor holding condition).

• This true bearing will become your true heading once all mooring line and anchor secured to the Rig.
• Which Mooring rope to be installed / utilized first.
• “Prior entering 500M Zone of the Rig for Tie up, you have to ascertain the Current direction by all means (There are a lot of methods to determine current direction). This is very importance to decide which mooring rope first to be installed for easy maneuver and the rig always asking about this once you got permission entering 500M Zone for tie up.
• If the current direction going towards “Bow of the rig”, you have to request for tied up with Stern line first. Once “stern line of the rig” already secured tied up to the “Starboard side (Stern) bollard of the vessel” This line will hold the vessel position from drifting towards bow of the rig due to blowing current direction and easy maneuver to install “Rig bow line” without using more vessel propulsion system.
• If the current direction going towards “Stern of the rig”, you have to request for tied up with Bow line first. Once “Bow line of the rig” already secured tied up to the “Port side (Stern) bollard of the vessel” This line will hold the vessel position from drifting towards stern of the rig due to blowing current direction and easy maneuver to install “Rig stern line” without using more vessel propulsion system.

• Remarks:
• If the vessel tied up at “Port side of the rig” The bow line of the rig will be tied up to the “Starboard side (Stern) bollard of the vessel” and the stern line of the rig will be tied up “Port side (Stern) bollard of the vessel”.
• If the vessel tied up at “Starboard side of the rig” The bow line of the rig will be tied up to the “Port side (Stern) bollard of the vessel” and the stern line of the rig will be tied up “Starboard side (Stern) bollard of the vessel”.

• Once all lines properly secured to the rig, the anchor holding test to be done prior stop the Engine (Heave up anchor with maximum winch power until all mooring line and anchor chain are tied and unable to pick up).

3. Where a Spar Buoy has been deployed at a Rig/Barge location.

The spar buoy is indicating the safe anchor drop position; you should drop your anchor between the Spar Buoy and the side of the Rig/Barge, and NEVER on the far side of the buoy (Prior approaching Rig which has a Spar buoy deployed – We must double check on the chart to obtain anchor restriction on this location).

“Spar Buoy” indicates this Rig has a close proximity of pipelines; take extra cautions prior approaching for anchor on this location.

Bow Line and Stern Line of The Rig.

See the below picture.

Example:

1. The Vessel received instruction to tie up at Port side of Rig Ensco-94 (South Safaniya Oilfield, KSA).

Rig Heading = 350 Degrees, Water depth = 11 M.

Current direction in the South Safaniya Oilfield; Ebb Tide set to (Going to) Northwest, Flood Tide set to (Going to) Southeast.

Please explain how to execute this job?.

Answer:

• Obtain anchor position as follows:
• True bearing = 350 – 60 = 290 Degrees.
• Distance = 0.18 NM (With this distance, anchor utilized at about 8 – 9 Shackle in water, (The distance depend on water depth, Existing of pipelines/cable at Rig location and seabed holding condition).

• Set ERBL (True bearing) on the Radar 290 degrees with distance 0.18 NM from the Rig.
• Check on the Tide table (Let say during this operation is “Ebb Tide”), Ebb Tide, Current direction set to (Going to) Northwest (Towards Bow of the Rig – Remember Rig heading is 350 Degrees/NW) – Stern line to be installed first for tied up.
• Follow the procedures for 500M Safety zone of the Rig/Installation as above (Check list to be completed and Request permission from the Rig to enter 500M safety Zone.
• Approach the Rig with a safe speed and Drop anchor at Position True bearing = 290 Degrees X distance 0.18 NM from the Rig.
• Request to install stern line first. "Ebb tide" (Current set to Northwest or towards bow of the rig).
• At safe distance from the Rig, Turning the vessel for stern approach and keep pay out the anchor chain.
• At safe distance required to tie up the mooring line, Stop pay out anchor chain to hold the vessel position and install stern line to the port side stern of the vessel as per plan previously (Current blowing towards bow of the Rig).
• Once all mooring line (Stern and Bow line) are secured, Heave up anchor until all mooring line and anchor chain tight and winch unable to heave up anchor at maximum power.
• The final position, ship’s heading is approximately about 290 Degrees (Same as true bearing for anchor position).
• If the anchor is holding, finish with engine and completed.

2. Vessel received instruction for Tied up at NBR-656 (South Safaniya Oilfield, KSA). Due to close proximity of pipe lines and cables in this location you are not allowed to anchoring at Port side of the Rig and anchoring only permitted at “Spar buoy installed at True bearing 030 Degrees X 400 M” from starboard side of the Rig.

Rig heading = 345 Degrees, Water depth = 4.6 M.

Current direction in the South Safaniya Oilfield; Ebb Tide set to (Going to) Northwest, Flood Tide set to (Going to) Southeast.

Please explain how to execute this job?.

Answer:

• Note: Where a Spar Buoy has been deployed at a Rig/Barge location, The spar buoy is indicating the safe anchor drop position; you should drop your anchor between the Spar Buoy and the side of the Rig/Barge, and NEVER on the far side of the buoy.
• In this location you should drop anchor between Spar buoy and starboard side of Rig NBR-656 (030 (T) X 400 M) – Inside of this true bearing and distance, NEVER far side of the spar buoy.
• Double check on the chart is required prior utilize anchor to avoid pipe lines.

• Check on the Tide tables (Let say in this case the Tide tables is showing “Flood Tide”), Flood Tide, Current direction set to (Going to) Southeast (Towards stern of the Rig – Remember Rig heading is 345 Degrees/NW) – Bow line to be installed first for tied up.
• Follow the procedures for 500M Safety zone of the Rig/Installation as above (Check list to be completed and Request permission from the Rig to enter 500M safety Zone.
• Approach the Rig with a safe speed and drop anchor at Position between “Spar buoy” and starboard side of the Rig (Drop anchor inside True bearing 030 Degrees X 400 M, NEVER far side of this True bearing and Set ERBL (True bearing) on the Radar from Rig (030 Degrees X 0.18 NM).
• Request to install Bow line first. "Flood tide' (Current set to Southeast or towards stern of the rig).
• At safe distance from the Rig, Turning the vessel for stern approach and keep pay out the anchor chain.
• At safe distance required to tie up the mooring line, stop pay out anchor chain to hold the vessel position and install Bow line to the portside stern of the vessel as per plan previously (Current blowing towards stern of the Rig).
• Once all mooring line secured, Heave up anchor until all mooring line and anchor chain tight and winch unable to heave up anchor at maximum power.
• The final position, ship’s heading is approximately about 030 Degrees (Same as true bearing for anchor position).
•  If the anchor is holding, finish with engine and completed. 

Have a safe voyage to all seafarers and hopefully this article may useful for your safe daily operation of AHTSS vessel. Any criticism and suggestion for this article is highly appreciated for improvement purpose.

Tanajib (KSA), 01 July 2015.

Zie Ahmadi