Sancti Petri Anchorage Guide

The Anchorage

Once inside the bar, anchor in 2–4m on excellent mud in the tidal channel. All-round protection — this is one of the most sheltered anchorages on the entire Atlantic coast of Spain. The inner channel is a calm, wind-free haven regardless of what is happening outside. The key challenge is the BAR at the entrance: the bar has approximately 2.5m depth at LW springs — approach only at half-tide rising for draft over 1.5m. The channel is buoyed but buoys move with sand — check Navily for current positions. Strong tidal currents in the channel (1.5–2 kt at springs) — anchor well clear of the main channel for large vessels. Dramatic ruins of Castillo de Sancti Petri on the island.

Setting Your Anchor

The bottom at Sancti Petri is primarily mud and sand with reliable holding when properly set. All depths are above chart datum — always calculate the current tidal height before approach using Cádiz, Huelva, or Tarifa tidal predictions (Spanish IHM tide tables available free at puertos.es). Allow for the full Atlantic tidal range of 3–4m at springs. Check the Posidonia DONIA app for the approach area to confirm no protected seagrass is present.

1. Approach in good visibility — confirm the tidal height gives adequate depth for your draft. If there is a bar or shoal on the approach, calculate precisely.
2. Calculate scope for maximum depth — at 2–5m plus up to 4m tidal rise, your maximum depth at HW may be 9m. Deploy minimum 7:1 scope accounting for the full tidal range.
3. Lie to the current, not the wind — in tidal waters the boat swings on the tidal stream. Drop the anchor into the current and pay out chain steadily. Allow for the swinging circle to change direction as the tide reverses.
4. Set firmly in reverse — 30–60 seconds moderate throttle astern to bury the anchor.
5. Take a GPS bearing — note the set position and verify your swinging circle is clear of other boats and the shore on both the flood and ebb tidal directions.

Recommended anchor types: SPADE, Rocna, CQR.

Overnight Anchoring & Anchor Alarm

Overnight stays at Sancti Petri are excellent — all-round protection means minimal boat movement.

Set your GPS anchor alarm to 70m radius before going below. 70m for 2–5m on excellent mud. Complete all-round protection inside. The alarm radius is tight due to the narrow channel — anchor close to the sides but with the circle clear of the main channel. Monitor tidal current direction as boat swings on channel flow.

Atlantic tidal note: In the Gulf of Cádiz with 3–4m tidal range, Atlantic swell, and the risk of the Levante developing overnight, your anchor watch must be reliable. The Levante (E wind) can strengthen to F7–8 within a few hours — if it is forecast, ensure you are in a W-facing anchorage (Bolonia, Bahía de Algeciras) rather than an E-facing position. Check the Tarifa MRCC forecast (VHF Ch 10) before settling for the night.

May–October. Best in summer when the Atlantic swell is more settled and the bar is easier to identify. Approach from the S in the Atlantic swell only in calm conditions — the outer bar area can be rough in SW swell. Not recommended in winter Atlantic storm season.

Navigation Hazards

• BAR: 2.5m at LW springs — CRITICAL tidal timing required. Do not attempt at LW. Check local conditions before entry.
• Shifting sandbar — buoy positions change; use Navily for current marking
• Tidal stream in channel 1.5–2 kt — enter with favourable (flood) current
• No facilities inside — arrive self-sufficient with fuel and provisions
• Mobile signal weak inside channel — check forecast before entry

Rules & Regulations

• Anchoring fee: Free
• Key restrictions: Keep clear of main channel for coastal traffic. The area around the castle island is a protected historical site — no landing on the island itself (though you can circumnavigate by dinghy). Speed limit 3 kt in the channel.

This is Atlantic water — Posidonia seagrass (protected Mediterranean species) is not present in Gulf of Cádiz anchorages. Standard good anchoring practice applies: avoid anchoring over rocky ground, use appropriate chain length, and set firmly before considering the anchor secure.

Facilities

• Fresh water: Not available on site — nearest: Conil de la Frontera (4nm)
• Fuel: Not available — nearest: Conil de la Frontera (4nm)
• Restaurant: None — nearest at Conil de la Frontera (4nm)
• Provisions: None on site — Conil de la Frontera (4nm)

Skipper's Tips

1. Draft calculation: add 2.5m (LW depth) to the tidal height at time of entry = actual depth over bar. For 1.8m draft, minimum tidal height needed above LW = 1.8m + safety margin (0.5m) = need at least 2.3m of tide. Check Conil de la Frontera tidal tables (nearest tidal station).
2. Local fishing boats in the channel know the exact current bar depth — hail them on VHF Ch 16 or in the anchorage.
3. The castle (Castillo de Sancti Petri) is hauntingly beautiful at sunset — said to be the site of the Temple of Hercules from Roman times.
4. This anchorage is unknown to most foreign cruisers — a genuine hidden gem. Spanish yachts from Cádiz use it regularly.