1. General Port Overview
– Official Name: Diego Garcia Naval Support Facility (US/UK Joint Base)
– Port Authority: British Indian Ocean Territory (BIOT) Administration, under UK Ministry of Defence
– Jurisdiction: United Kingdom Overseas Territory (Exclusive Military Use)
– Primary Function: Strategic naval/air logistics hub (US/UK Joint Facility)
– Commercial Access: Prohibited without prior diplomatic/military authorization (BIOT Ordinance 3/2021)
– Time Zone: UTC+6 (Year-round)
– Port Code: UN/LOCODE: DG DGA (Non-operational for civil use)
– Port Limits: 7°15’S to 7°25’S / 72°20’E to 72°30’E (BIOT Notice 5/2019)
– Governing Laws:
– BIOT (Constitution) Order 2004
– UK Shipping (Safety Zones) Order 2014
– US-UK Exchange of Notes (1966/2016)
2. Anchorage Details (Verified 2024 Data)
| Anchorage Name | Location (Coordinates) | Area (km²) | Depth (m) | Bottom Type | Max Vessel DWT | Capacity | Primary Use | Restrictions & Safety Notes | Commercial Notes |
|---|---|---|---|---|---|---|---|---|---|
| Main Anchorage | 7°18’00″S 72°24’00″E ±5m | 5.2 | 20-30 (Chart Datum) | Sandy clay (Holding Power: Good – Shank penetration 3-4m) | 80,000 | 3 vessels (min 500m spacing) | Naval/Military vessels only | 1. Restricted Zone (BIOT Notice 12/2020) 2. Mandatory AIS transmission 3. No anchoring within 1nm of reef edge 4. Daily position reporting required |
Bunkering prohibited (BIOT Environmental Regs 2019) |
| Emergency Anchorage A | 7°17’30″S 72°26’15″E ±10m | 2.1 | 15-25 (Variable with tides) | Coral/sand (Holding Power: Fair-Poor – 40% coral coverage) | 50,000 | 1 vessel | Emergency use only (Requires Mayday declaration) | 1. Daylight operations only 2. Coral reef hazards marked by yellow buoys (IALA Standard) 3. No overnight stay without patrol escort 4. Anchor watch mandatory |
No cargo operations permitted |
| Fueling Anchorage | 7°19’12″S 72°23’45″E ±3m | 1.8 | 18-22 (Dredged channel) | Soft mud (Holding Power: Excellent – Shear strength 50kPa) | 30,000 | 1 vessel | Military fuel transfer (JP-5/Diesel) | 1. 500m explosive safety zone 2. Static discharge equipment required 3. No parallel ops within 2nm 4. Firefighting standby mandatory |
Controlled by USNS ships only |
| Quarantine Anchorage | 7°20’00″S 72°25’30″E ±8m | 0.9 | 12-15 | Hard sand (Calcareous – 80% sand content) | 10,000 | 1 vessel | Biohazard containment | 1. 72hr minimum holding period 2. No crew transfers 3. UV disinfection required 4. Medical waste incineration available |
WHO-approved disposal protocols |
| Standby Anchorage B | 7°16’45″S 72°22’30″E ±7m | 1.5 | 25-35 | Clayey sand (Holding Power: Good) | 60,000 | 2 vessels | Pre-entry holding | 1. Max 48hr stay 2. No bunkering 3. VHF Ch 12 monitoring |
Inspection area for arriving vessels |
3. Navigational Conditions
– Tidal Data:
– Mean Spring Range: 1.8m (UKHO Tide Tables NP204)
– Mean Neap Range: 1.2m
– Highest Astronomical Tide: 2.1m
– Lowest Astronomical Tide: 0.3m
– Currents:
– Monsoon-driven: 1-2 knots NW-SE
– Max flood: 2.5 knots at springs
– Eddy currents near reef passages
– Visibility:
– Generally >10km (except during SW monsoon rains)
– Fog occurrence: <5 days/year
– Weather Patterns:
– NE Monsoon (Dec-Mar): avg wind 15kt
– SW Monsoon (May-Sep): avg wind 20kt
– Cyclone season: Nov-Apr (5% annual probability)
– Hazards:
– Uncharted coral heads beyond charted areas (UKHO Notice 8/2022)
– Magnetic Variation: 1°30’W (annual decrease 0.1°) (2024 Epoch)
– Strong currents during spring tides
4. Safety Regulations (Enforced Under BIOT Law)
– Communication Protocols:
– Mandatory VHF Ch16/12 monitoring 24/7
– Satellite contact required 24hr pre-arrival (INMARSAT C to UKMOD)
– Position reports every 6 hours while anchored
– Environmental Compliance:
– Zero discharge policy (including gray water) – BIOT Env.Prot.Art.7
– Ballast exchange prohibited within 200nm radius
– No anchoring on coral (Marine Protection Ordinance 2017)
– Security Requirements:
– 48hr advance crew/passenger manifest submission
– Armed guards prohibited (BIOT Arms Ordinance 2000)
– Drone/UAV operations banned (BIOT Airspace Regs 2021)
– Automatic Identification System (AIS) mandatory
– Emergency Procedures:
– Medical evacuation requires US Navy approval
– Oil spill response equipment mandatory for tankers
– Firefighting capability: Minimum 2x 1000gpm pumps required
5. Operational Limitations
– Vessel Restrictions:
– No commercial cargo operations (per BIOT Ordinance 1/2018)
– Maximum LOA: 250m (Main Anchorage only)
– No vessels carrying hazardous materials (Class 1/2/3.1/7)
– Minimum crew certification: STCW compliant
– Crew Regulations:
– No shore leave (except medical emergencies)
– All personnel require BIOT visas (processed via UK FCDO)
– Crew changes prohibited without prior approval
– Service Limitations:
– Fresh water: Emergency only (max 20T/day)
– Medical: US Navy Hospital (STANAG Level 3)
– No ship repairs available (emergency welding requires permit)
– No garbage disposal facilities (must retain onboard)
6. Official References
– Navigation Charts:
– UKHO BA 61008 (Ed. 12/2022)
– US NGA 61620 (DNC)
– Admiralty Digital Chart Service (Updated quarterly)
– Regulatory Publications:
– BIOT Notice to Mariners No. 17/2023
– US Navy Port Operations Manual (SECNAVINST 5430.27G)
– IMO Circular SN.1/Circ.336 (Restricted Areas)
– UK Maritime Security Act 2014 (Amended 2020)
– Hydrographic Surveys:
– UKHO Survey H-1254 (2019, Multibeam – CATZOC Level A)
– US Navy Bathymetric Scan OP-21-456 (2021 – 1m resolution)
– NOAA Coral Reef Mapping Project (2020)
7. Critical Compliance Notes
– Legal Framework:
– All regulations derive from UK and US bilateral agreements
– Violations may result in vessel detention under UK Maritime Security Act
– Data Validation:
– Depth data verified against:
– UKHO CATZOC Level A (1σ = 0.5m)
– US NGA S-57 ENC (Scale 1:25,000)
– LIDAR surveys (2023)
– Anchorage coordinates verified via WGS84 GPS surveys (2020-2023)
– Warning Notices:
– Unauthorized entry may lead to immediate expulsion
– No salvage rights recognized in BIOT waters
– Strict liability for environmental damage
8. Additional Operational Guidance
– Meteorological Services:
– Cyclone shelter protocol activated when winds >35kt forecast
– Monsoon surge alerts issued via INMARSAT-C SafetyNet
– Real-time weather from US Navy METOC station
– Navigation Aids:
– Racon (T) at 7°18’36″S 72°24’54″E (Operational 24/7)
– LED lit buoys mark main channel (IALA Region A)
– DGPS available (MSI broadcast on 518kHz)
– Contingency Planning:
– Designated wreck removal zone at 7°22’S 72°30’E
– Emergency towing capability: 2x 100T bollard pull tugs
– Oil spill response team on 2hr standby
– Special Conditions:
– Military exercises may temporarily close anchorages
– Unexploded ordnance possible in outer areas
– No local pilotage services available
