Île d'Oléron — Grand Large (Vert Bois)
Plage de Vert Bois · W Oléron ocean anchorage
45°54.7'N 001°21.1'W
Depth (HW)
3–7m
Bottom
sand
Alarm Radius
90m
Holding
Good Holding
Recommended Anchor Alarm Radius
90m
90m on sand. CALM DAYS ONLY — this is an open Atlantic ocean beach; only anchor here in glass-calm conditions with no W swell forecast for the full period you plan to stay. Set the alarm and monitor swell height continuously. Any deterioration: weigh anchor immediately.
About This Anchorage
Plage de Vert Bois on the W coast of Île d'Oléron is one of the great wild beach anchorages of the French Atlantic — a vast white sand beach backed by pine forests (Forêt des Saumonards), no development, no crowds, total solitude. However, it is entirely exposed to the Atlantic Ocean from W through N and S. This anchorage is only possible in genuinely calm conditions with a settled high-pressure pattern and zero W swell. On the rare days when this is achievable — typically glassy mornings in June or September — it is an extraordinary experience. Monitoring is essential: Atlantic swell builds quickly and with little warning. Never overnight here without a guaranteed forecast.
Protected From
E · NE
Exposed To
W · NW · SW · S · N
Setting Your Anchor
7:1 Scope — Atlantic Tidal Standard
With a 4–5m spring tidal range, the depth at your anchor point can change by up to 5m overnight. Use 7:1 scope minimum — in 4m at HW, lay 28m of chain as a minimum (excluding depth + freeboard). At LW (potentially 1–2m), the scope ratio increases automatically, providing extra catenary. Always verify the anchor is set firmly before reducing engine revs.
Tidal Depth Calculation
Before anchoring, calculate the depth at maximum LW (spring LW) using the SHOM tide tables for the nearest standard port. Subtract the spring tidal range (4–5m) from your HW depth to get the LW depth. For a 1.5m draft vessel, you need at least 1.8m at LW springs (with 0.3m safety margin) — if the anchorage will be shallower, either move to deeper water or ensure you are comfortable taking the ground on sand.
Oyster Stake Avoidance
Always check your proposed anchor position against the SHOM chart for oyster farm boundaries. At HW, oyster stakes may be submerged or barely visible — a dragging anchor on a falling tide can set you into a farm before the alarm sounds. Keep a minimum 200m clearance from all oyster farm boundary buoys.
Anchoring Rules
- Anchoring fee
- Free
- Maximum stay
- 1 days
- Permit required
- No
- Anchoring allowed
- Yes
Restrictions: CALM CONDITIONS ONLY — do not anchor overnight without a firm 24h settled forecast. Exit plan mandatory: any increase in W swell or wind above F2 from W/SW/NW requires immediate departure. This is an open Atlantic beach — treat accordingly.
Hazards
- !OPEN OCEAN exposure to W/NW/SW/S/N — completely untenable in any W swell; anchor here ONLY in flat calm conditions
- !Atlantic swell can build from 0.3m to 2m in under 2 hours — continuous monitoring required
- !Surf zone: approaching the beach by dinghy in any swell is dangerous
- !Tidal range 4–5m — anchor in 5–6m at HW for safe LW clearance on sand
Skipper's Tips
- →Check the Météo-France swell height forecast (not just wind) — a calm day can still have 1m+ residual Atlantic swell from a distant storm. Only anchor here when swell is under 0.3m.
- →Early morning in June: the best chance of glassy conditions — arrive at HW with the flood to carry you in, anchor, enjoy 3–4 hours, depart before the sea breeze builds.
- →The pine forest of Saumonards behind the beach is protected nature reserve — no vehicles, beautiful walks.
Facilities
Nearest provisions: Saint-Trojan-les-Bains (4nm)
Best Months & Season
June, September
June and September only, in genuinely settled high-pressure conditions. Not recommended for July–August (sea breezes too reliable from W). Day anchorage only — no overnight without confirmed settled 24h forecast.
Recommended Anchor Types
Nearby Anchorages
Sleep peacefully at Île d'Oléron — Grand Large (Vert Bois)
With a 4–5m tidal range overnight, your boat's position relative to nearby hazards changes as the depth drops. In July–August, neighbouring boats anchor close and the anchorage shifts with the tide. Safety Anchor Alarm continuously monitors your GPS position and sounds an instant alert if you drift outside your set 90m radius — so you can rest without worry.
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