Education / Vessel Types
PSV & AHTS Charter Guide
Platform Supply Vessel and Anchor Handling Tug Supply specifications, BIMCO SUPPLYTIME terms, Nigerian offshore operations, and deepwater oil & gas support vessel chartering.
By Pius Nobei, MBA
Updated August 2026
8,000
Max PSV DWT (MT)
390t
Max AHTS Bollard Pull
DP2
Dynamic Positioning
1,100m
Max Operating Depth
Overview
Offshore Support Vessels
Platform Supply Vessels (PSVs) and Anchor Handling Tug Supply (AHTS) vessels are the backbone of offshore oil and gas operations. PSVs transport essential supplies, including fuel, drilling fluids, cement, pipe, and provisions, between shore bases and offshore installations. AHTS vessels handle the critical task of positioning and anchoring drilling rigs, towing floating production units, and providing emergency response support.
In West Africa, Nigeria's deepwater fields drive the majority of PSV and AHTS demand. Fields like Bonga, Agbami, and Egina operate FPSOs in water depths exceeding 1,000 metres, requiring regular supply runs and occasional anchor handling campaigns. The Cabotage Act reserves these domestic offshore trades for Nigerian-flagged or Nigerian-operated vessels, creating specific chartering requirements.
Chartering PSVs and AHTS for Nigerian offshore operations requires understanding of NIMASA regulations, Cabotage compliance, and the operational demands of deepwater environments. Calmwaters Shipping arranges PSV and AHTS charters on BIMCO SUPPLYTIME terms with full regulatory compliance.
PSV Specifications
Deadweight (DWT)
3,000-8,000 MT
Deck Area
600-1,100 sqm
Positioning System
DP2 (Dynamic Positioning)
Service Speed
15-16 knots
Accommodation
25-70 persons
Cargo Tanks
Fuel oil, drill water, brine, pot water
Deck Cargo
Bulk, containers, pipes, equipment
BHP Range
5,000-12,000 BHP
AHTS Overview
Anchor Handling Tug Supply
AHTS vessels are purpose-built for the demanding task of anchor handling and rig moves. They combine the supply capabilities of a PSV with powerful winches, towing equipment, and high bollard pull. AHTS vessels can handle anchors weighing up to 30 tonnes in water depths exceeding 2,000 metres, and tow floating drilling rigs and production units across ocean distances.
Modern AHTS vessels are equipped with Dynamic Positioning (DP) systems, ROV launch and recovery systems, fire-fighting equipment, and emergency response capabilities. The versatile nature of AHTS vessels makes them essential for drilling campaigns, rig relocations, decommissioning operations, and offshore construction support.
AHTS Specifications
Bollard Pull
50-390 tonnes
Length Overall (LOA)
60-95 metres
Beam (Width)
16-24 metres
Deadweight (DWT)
875-4,800 MT
Service Speed
15-18.5 knots
Accommodation
18-70 persons
Deck Area
120-1,000 sqm
Winch Capacity
100-400 tonnes brake holding
Nigerian Offshore Fields
Deepwater Operations Requiring PSV/AHTS Support
| Field | Operator | Water Depth | Vessels | FPSO Capacity |
|---|---|---|---|---|
| Bonga | Shell | 1,050m | PSV + AHTS | Bonga FPSO (225,000 bpd) |
| Agbami | Chevron | 1,470m | PSV + AHTS | Agbami FPSO (250,000 bpd) |
| Egina | TotalEnergies | 1,600m | PSV + AHTS | Egina FPSO (200,000 bpd) |
| Preowei | Seplat | 1,100m | PSV | Preowei FPSO (150,000 bpd) |
| Akpo | TotalEnergies | 1,300m | PSV + AHTS | Akpo FPSO (180,000 bpd) |
Charter Party Forms
BIMCO SUPPLYTIME for Offshore Vessels
BIMCO SUPPLYTIME is the industry-standard charter party form for offshore support vessels. The 2017 edition addresses modern offshore operations including Dynamic Positioning requirements, weather downtime provisions, standby rates, and vessel sharing agreements. SUPPLYTIME 2005 remains in use for older contracts.
Key provisions in SUPPLYTIME include hire payment terms, off-hire events (weather, mechanical failure), master's authority, cargo limitations, and insurance requirements. For Nigerian operations, additional clauses address Cabotage compliance, NIMASA registration, and local content requirements under the Nigerian Oil and Gas Industry Content Development Act.
Charter Considerations
Cabotage Compliance
Vessels must comply with the Coastal and Inland Shipping (Cabotage) Act 2003 for domestic offshore trades. Nigerian flag or Cabotage waiver required.
NIMASA Registration
All vessels operating in Nigerian waters must be registered with NIMASA. Certificate of registration and valid class certificates required.
DP Requirements
Deepwater operations typically require DP2 or DP3 class vessels. Charterer specifies minimum DP class in charter party.
Insurance Coverage
P&I insurance, H&M insurance, and war risk coverage mandatory. Nigerian local insurance requirements apply for Cabotage vessels.
Frequently Asked Questions
PSV & AHTS Charter FAQ
What is the difference between a PSV and an AHTS?
A PSV (Platform Supply Vessel) transports cargo, fuel, and supplies to and from offshore installations. An AHTS (Anchor Handling Tug Supply) performs anchor handling for rig moves, tows floating structures, and also carries supplies. AHTS vessels have stronger winches and higher bollard pull, while PSVs have larger deck areas and cargo capacity.
What charter party form is used for PSVs and AHTS?
BIMCO SUPPLYTIME is the standard charter party form for offshore support vessels including PSVs and AHTS. It covers time charter arrangements with specific provisions for offshore operations, weather downtime, and vessel positioning. Calmwaters Shipping uses SUPPLYTIME 2017 or 2005 editions for Nigerian offshore charters.
What are the main offshore fields requiring PSV/AHTS support in Nigeria?
Key Nigerian deepwater fields requiring PSV/AHTS support include Bonga (Shell, 1,050m water depth), Agbami (Chevron, 1,470m), Egina (TotalEnergies, 1,600m), and Preowei (Seplat). These fields operate FPSOs and require regular supply runs and occasional anchor handling for drilling rigs and floaters.
What are typical PSV and AHTS charter durations in West Africa?
PSV charters in West Africa range from short-term (1-3 months) for project support to long-term (1-3 years) for field maintenance contracts. AHTS charters are often tied to drilling campaigns (60-120 days) or rig move campaigns. Standing contracts with oil majors provide the most stable demand.
Offshore Vessel Charter Support
Charter PSVs & AHTS for Nigerian Offshore
Calmwaters Shipping arranges PSV and AHTS charters for deepwater oil and gas operations off Nigeria. BIMCO SUPPLYTIME terms. NPA Licensed Agent. Full Cabotage and NIMASA compliance.