How and Why do Boats Anchor at Sea? In-Depth Explanation!


By Ed Dunens - Sea anchor, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=64498691
Sea anchor deployed in the water

Doing big ocean crossings can be one of the most interesting things you can do, something that struck me when I was planning to do a big crossing with my first boat was, How do I anchor at sea? a few years into sailing it’s no longer a big deal. but I have understood many of you out there are interested in the answer so I thought id offer my 5 cents in explaining in. (and also, I would like to apologize for the intended “in-depth” pun above 😉 )

As always, ill try to answer your question in the shortest way possible, and further down you will get a little meatier explanation.

By the sea I mean waters that are hundreds or thousands of meters deep where you chain anchor is never long enough to reach the bottom, So How and why do boats anchor at sea?

The only way boats can anchor while at sea is to use a sea anchor (also known as drift sock, boat brake, drift anchor, para-anchor). This type of anchor works by rightening and slowing down the boat so that the boat will receive the waves from either the bow (usually) or stern and not to its side.

If the boat is not kept that way a big wave may easily capsize the boat. It’s important to know that this type of anchor doesn’t stop the boat from moving relative to the ground instead it works by braking the boat speed relative to the wind and waves.

A boat on a sea anchor will still drift the but it will drift far less in the same amount of time, basically, there are two functions of a sea anchor.

  1. The sea anchor can work as a safety device in heavy weather, as mentioned above it can keep the boat almost still at a relative angle to the waves thus keeping the waves from hitting its side and potentially capsizing. this is done by reducing the boat speed to an almost complete stop, minimizing the risk from surfing down a wave, and burying the bows in the next wave. this avoids the risk of pitchpoling or flipping upside down. There are also smaller types of sea anchors, so-called Storm drogues that are smaller and specifically intended to be used off the stern of a yacht when in heavy seas. The drogues are better suited for heavy wind sailing since it will only slow the boat down while the sea anchor is much bigger and will make the boat come to an almost complete stop.
  1. The second use is to make the boat not drift as much with the wind, this is mainly used by fishing boats to maintain their position without having to use their engines. These are sometimes called drift anchors or drift socks. This is also how you would anchor a boat in the middle of the sea if trying to stay at the same place.

How to deploy a Sea Anchor or Storm Drogue

Deploying a storm drogue or sea anchor is a easy three step mission

  1. Firstly you will deploy what is called a trip line, basically, a long rope with a buoy on the end of it made to collapse the parachute when you want to recover your sea anchor after the storm. This is thrown off the windward side of the boat.
  2. once the boat and the anchor have drifted apart the next step is to throw the actual sea anchor parachute into the water, this is done on the same side as the trip line.
  3. The third and final step is to attach the anchor rode(rope or chain) to the boat.

How to retrieve a Sea Anchor or storm drogue

Retrievning the anchor is a simple matter, at least in calm conditions.

  1. Hook the trip line buoy with a boat hook, pull the buoy and tripline on board, when pulling the tripline the parachute will collapse and collecting it should be fairly easy.
  2. Before packing it up make sure you check the condition that the next time you use it you known its all ready to go. Especially make sure that all places where there has been chafing or other types of wear are carefully looked through.

Other ways of riding out a storm “Heave to”

“Heave to” is a maneuver for a sailboat to come to a stop this is achieved by fixing the rudders and sails, this is extra useful if your sailing short-handed, that is only one person on board, and you need to do maintenance or go below deck to fix something. the maneuver is very old and has some great stories connected to it and as proven its value as a storm tactic over and over again. Its been described as “parking your boat without anchoring”.

By Nigelj - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=16016415

The idea of this method is instead of using the energy of the wind to sail the boat forward, use one sail to push the boat backward, and one sail to push forward. Getting these to work in balance will make the boat stop and fixing the rudder so the boat cant turn will make the boat have a fixed angle towards the wind.

While hove-to the boat may drift at 1-2 knots so maintaining an outlook is still of great importance. although instead of having the entire crew sail the boat in stormy conditions now it only takes one person to check that “the heave to ” method is working the way it should and the boat is not turning in to the wind to much or drifting to close to shore.

When the waves and winds are too tough on you and you’re not covering much ground towards your destination, heave to might be your best friend. it can allow the crew to rest, it spares the boat from continuous pounding of sailing into the wind (especially if you’re on a catamaran ).

it is also a method you can use when the weather is good and you want to turn your catamaran into a big floating court because maybe you want to get some repairs done or just enjoy the beautiful weather before you head back into port.

Do it yourself storm drogue

If you find yourself in the situation where you would want to use a storm drogue but either you don’t have one or the one that you have is not working enough or not at all there are still things you can do.

One way is to connect a long rope from one stern to the other and let it trail in the water, the resistance from that warp (as it is called in boat language) will brake the boat in the same way as a parachute although not as effective.

Adjusting the speed is simply done by either shortening or lengthening the rope.

There are some alterations to this method, that is, instead of having a full loop you can make is so that there are two parallel ropes trailing, and shortening one will make the boat wanting to turn to one side which will help to steer the boat in case balancing the sails are difficult.

Gabo

Owner of CatamaranFreedom.com. A minimalist that has lived in a caravan in Sweden, 35ft Monohull in the Bahamas, and right now in his self-built Van. He just started the next adventure, to circumnavigate the world on a Catamaran!

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