developed and seo specialist Franco Danese

How to drop the anchor without destroying the seabed

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Isle Porquerolles, France, 28 september 2016.

When cruising, there is nothing better than dropping the anchor to fully enjoy the surrounding nature. However, some precautions are essential not to damage the seabed.

anchor dropping

In this case, both chain and anchor have been dropped in the sand (and not in poseidonia).

First of all, watch out for rocky seabeds: when anchoring on rock, there is a greater chance that the anchor will get aground (and if you do not have a good diver on board, there will be trouble) and that the chain and the anchor destroy the flora and fauna that live there. The other “criminal” action is mooring on the Posidonia meadows (useless mooring, because the anchor will never hold well). Meadows constitute real forests and are the green lung of our sea. They are a source of nourishment for fish and crustaceans and consolidate the seabed counteracting coastal erosion.


Both the anchor and chain have a strong impact on the meadows because they tear roots, rhizomes and leaves: every time you pull the anchor away, on average, know that you are destroying 34 bundles of positions (one bundle contains 5 leaves), or one square meter. And just one square meter of posidonia can produce 14 liters of oxygen per day. “So much it regenerates”, you say: false. Posidonia is not an alga but a real plant, which grows only one centimeter per year and is very fragile.

Caulerpa Racemosa (source: Wikipedia, author: Nick Hobgood)


The same applies to all the other types of algae. Dropping the anchor there might facilitate the spread of invasive non-endemic species: this is the case of Caulerpa taxifolia and Caulerpa racemosa, of tropical origin (they grow rapidly and there are no animals in the Mediterranean that feed on them), a serious danger for our ecosystem. An anchor thrown in an area infested with Caulerpa spreads dozens of cuttings and promotes their propagation.


Sand is the only safe option. If the water is is cloudy and you can’t see the bottom, use the nautical charts and maps of your chartplotter to find a sandy area where you can drop anchor (in any case, the view will always be clearer than rocky bottoms and seaweed). Here you will do as little damage to the ecosystem as possible.


The choice of the anchor is essential. There are many types of anchors but Lewman, Spade, Rocna models guarantee better grip than traditional “flat” anchora ( Fortress, Britany…).
Ma se e solo se avrete l’ancora giusta. Sullo scorso numero del Giornale della Vela (da pagina 29) abbiamo messo a confronto sedici modelli di ancora scoprendo che le ancore a vomere (Lewmar, Spade, Rocna) garantiscono una tenuta molto migliore su sabbia rispetto alle tradizionali ancore “piatte” (Fortress, Britany…). Drop the anchor only if you are sure that the sandy area under your boat is large enough to also accommodate the chain (which, remember, for an optimal mooring it must be at least three times the seabed). And to return to the subject of invasive species: if you find fragments of Caulerpa on the chain or anchor, once set sail, dispose of them in a trash can and do not throw them back into the sea.


Good behaviour is fundamental. Do not discharge black water and gray water (it would be better to have two dedicated tanks for ‘responsible’ unloading in port), do not throw waste into the sea, do not be noisy and if you want to fish, find out about the regulations in force in the area.


1. Approach the anchoring area with the wind in front, identifying the sandy area on which you want to bottom.

2. With the boat stationary, start lowering the anchor. On sand, the “ploughshare” models (Lewmar, Spade, Rocna) hold much better than the “flat” ones.
3. Spin the chain as the boat moves back. For a safe anchorage, the cap (the length of the lowered chain) must be at least three times greater than the depth (if the bottom is 10 meters, row at least 30 meters). It is useful to have colored meter counters every ten meters of chain to know how to adjust.
4. Wait for the boat to position head to wind and check the hold of the anchor, observing conspicuous points on the ground for a few minutes (or if there is a good diver on board, you can dive to check that the ploughshare has caught on seabed).
5. When you need to lift anchor, bring the boat over the anchor before starting to pull it up. To facilitate this operation, the installation of a buoy may help.




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