| Anchorage Name | Location (Coordinates) | Area (km²) | Depth (m) | Bottom Type | Max Vessel DWT | Capacity | Primary Use | Restrictions & Safety Notes | Commercial Notes |
|---|---|---|---|---|---|---|---|---|---|
| Miyako Outer Anchorage | 24°47’30″N, 125°16’00″E (WGS84) | 1.2 | 20-30 | Sandy mud (holding power: 3–5 t/m²) | 50,000 | 5 vessels | Waiting, cargo transfer | NE monsoon winds (Oct–Apr) may cause dragging; minimum 4:1 scope required. | Bunkering prohibited; fresh water supply: 50t/hr max. |
| Miyako Inner Anchorage | 24°48’00″N, 125°17’30″E (WGS84) | 0.8 | 10-15 | Soft mud (holding power: 2–3 t/m²) | 20,000 | 3 vessels | Coastal vessels, fishing | Tidal currents reach 3.5 knots during spring tides; daylight operations only. | Fishing vessel priority 0500–1800 LT. |
| Emergency Anchorage A | 24°46’45″N, 125°15’15″E (WGS84) | 0.5 | 15-20 | Rocky with coral patches (poor holding) | 30,000 | 2 vessels | Emergency use only | Requires double anchors; prohibited during typhoon alerts (JMA Category ≥3). | No commercial services available. |
| Quarantine Anchorage | 24°47’10″N, 125°15’45″E (WGS84) | 0.3 | 18-22 | Hard sand (holding power: 4 t/m²) | 40,000 | 1 vessel | Health inspections | Mandatory 12-hour isolation prior to port entry (Japan Quarantine Law Art. 12). | Medical waste disposal available. |
Additional Anchorage Data
– **Tidal Information**:
– Mean spring range: 2.1 m (Japan Hydrographic Department Tide Tables 2023).
– Highest recorded tide: 2.8 m (Typhoon Haishen, 2020).
– **Pilotage**:
– Compulsory for vessels >200 GT foreign-flagged (IMO Resolution A.960(23)).
– Pilot boarding point: 24°46’00″N, 125°14’30″E (VHF Ch 12).
– **Anchorage Regulations**:
– Anchoring prohibited within 500m of submarine cables (Japan Coast Guard Notice 2022-5).
– Mandatory 1-hour position reporting interval via VHF Ch 16.
Navigational Warnings
– **Typhoon Procedures**:
– Port closes when JMA issues Typhoon Warning (sustained winds ≥15 m/s).
– Vessels >10,000 DWT must vacate within 12 hours of warning.
– **Coral Reef Protection**:
– No anchoring within Marine Protected Areas (24°48’30″N–24°49’00″N).
– Penalties up to ¥5 million for reef damage (Okinawa Prefecture Environmental Ordinance).
– **Fishing Gear Hazards**:
– 80+ unmarked fish aggregating devices (FADs) within 5 nm radius.
– Nighttime navigation discouraged in inner anchorage.
Port Services
– **Bunkering**:
– MGO only (max sulfur 0.1% per Japan Clean Air Act).
– Barge capacity: 300t; 72-hour advance notice required.
– **Repairs**:
– Emergency welding/hull patches available (ISO 3834-2 certified).
– Nearest dry dock: Naha Port (300 nm NW).
– **Crew Services**:
– Medical clinic (24/7, JIS Q 9100 certified).
– Shore leave permitted with valid IMMC.
