ground tackle (anchoring and mooring)

Ground Tackle – Anchoring and Mooring

Quartermaster Requirement 8

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Quartermaster Requirement 8

Teach the Ordinary and Able requirements No. 8, Ground Tackle, to a crew.

Know the methods of bringing a boat to anchor or mooring with special emphasis on wind and current with respect to the vessel's course and speed.

Take charge of the craft used by your ship and give all commands to the crew for anchoring and weighing anchor in several different wind and current situations.

Take charge of the craft used by your ship and give all commands to the crew for picking up a mooring buoy and properly mooring the vessel in several wind and current situations. Note: Depending on the type of craft used by your ship, this requirement

may be met either under sail or power.

Reference: "Ground Tackle" on page 145.

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Anchor Rode

The rode is the line and/or chain which goes to an anchor. It is often composed of both chain and rope.

The chain is attached to the anchor and it helps the anchor to lie flat on the bottom. This has three benefits: The chain lies flat on the bottom

and increases the horizontal pull on the anchor. This will increase the anchor's purchase.

The chain will not chafe as it lies on and is pulled across the bottom.

The chain acts as a shock absorber as the boat intermittently pulls on the rode, lifting the chain off the bottom.

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Purchase

Be sure that the anchor has a good purchase on the water's bottom or it will drag and the boat will drift.

Check the purchase by observing the tension on the rode and any change in position of the boat as the boat is placed in reverse.

While at anchor, intermittently check the tension on the rode as the boat's bow raises and lowers with the waves.

Also take several compass fixes and/or GPS positions to aid in determining if the boat is drifting and pulling the anchor.

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Scope

As a general guide, let out at least seven times the rode as the depth of the water plus the boat's freeboard (distance from the water surface to the deck) This ratio is called the anchoring scope. Dragging anchor is often caused by not letting

out enough rode.

Scope may be decreased to 5:1 if an all chain rode is used.

Scope may be increased in high wind or wave conditions.

Check the depth of the water where you anchor in relationship to the tide. For example, if you anchor with a 7:1 scope at

low tide in six feet of water and a six foot tide comes in, your scope will be reduced to 3.5:1

Or you may inadvertently become grounded.

Sailor's Tip: Place fathom or foot markers on the rode to help judge how much line has been let out.

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Swing

If a single anchor is placed, your boat will swing around the anchor as the direction of wind changes. This is especially true on

the coast where one encounters land and sea breezes.

The water must be deep enough for anchorage along the entire arch of this swing.

If less swing is desired, set two anchors at 180 degrees from each other.

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Crowded Anchorage

Boats anchored next to each other with a different swing radius are at risk to drift into each other if the current or wind changes. Look at the other boats and

note the type and the angle of their rodes to the water. This will help you judge the

amount of rode let out and give an idea of the swing radius of the other boats.

If a boat has an all chain rode, it may have a 5:1 or less scope and have a smaller swinging radius than a boat with a combination chain and rope line.

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Desired Anchorage

Always anchor in a similar fashion as the boat next to you or the two boats may drift into each other. For example: If your boat is fixed

in place with two anchors and the other boat has a single anchor, the other boat may be blown into your boat.

A good anchorage has the following characteristics: Protected from wind and waves &

swells. Enough depth at low tide along the

full swing of the rode. Enough space along the full swing

of the rode. Good bottom which will hold an

anchor.

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Trip Line

One may place a second line (trip line) to the head of the anchor. There is usually a metal loop to

allow for the placement. Bring the line up to the surface

and attach to a flotation device. Using this line the anchor can

be pulled out by its head and will be easy to remove.

The length of the trip line is equal to the water depth at high tide plus 5 to 10 feet.

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Anchor Commands

Aweigh AnchorTo raise an anchor off the bottom

Drop AnchorTo lower an anchor gently to the bottom

Take In SlackThe deckhands are to pull in the slack and snub it around a cleat.

Take A StrainThe deckhands are to pull on the line named, snubbing it around the cleat but allowing a little slippage.

Ease OffThe line is allowed to slip more freely.

HoldThis means to check the line temporarily.

Secure LinesTie the lines down permanently

Back AnchorCarry out a smaller anchor ahead of the one by which the vessels rides to take off some of the strain.

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Using Two Anchors

Using two anchors is a difficult maneuver. Reduces the swing radius of

the sailboat. Increases holding power in

heavy weather.

The tension on the anchor rodes is important when setting the second anchor  Too much tension may cause

the first anchor to break loose Too little tension on the rode

may cause it to go astern and foul your prop.

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Setting Two Anchors

Drop anchor.

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Setting Two Anchors

Drop anchor.

Use intermittent reverse thrust.

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Setting Two Anchors

Drop anchor.

Use intermittent reverse thrust.

Turn the boat and use forward thrust. KEEP THE RODE AWAY

FROM THE PROP.

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Setting Two Anchors

Drop anchor.

Use intermittent reverse thrust.

Turn the boat and use forward thrust. KEEP THE RODE AWAY

FROM THE PROP.

Drop the second anchor.

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Setting Two Anchors

Drop anchor.

Use intermittent reverse thrust.

Turn the boat and use forward thrust. KEEP THE RODE AWAY

FROM THE PROP.

Drop the second anchor.

Use reverse thrust to position the boat between the two anchors.

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Setting Two Anchors

Drop anchor.

Use intermittent reverse thrust.

Turn the boat and use forward thrust. KEEP THE RODE AWAY

FROM THE PROP.

Drop the second anchor.

Use reverse thrust to position the boat between the two anchors.

The final angle between the two anchor rodes should be between 30° and 60°.

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Mediterranean Mooring

Commonly found in Europe, South and Central America. Maximizes the number of boats

which can be docked to a pier. 

Each boat is docked with its stern to the pier with a rode and anchor going forward, away from the pier.  Boats are then docked next to

each other.   During the maneuver the anchor is

set and the boat is backed into position. 

Prop-walk can create difficulty staying on course. 

Be careful not to put too much tension on the rode when backing up or the anchor may break loose

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Mediterranean Mooring

Use intermittent forward thrust to maneuver to where you will drop anchor.

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Mediterranean Mooring

Use intermittent forward thrust to maneuver to where you will drop anchor.

Drop anchor.

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Mediterranean Mooring

Use intermittent forward thrust to maneuver to where you will drop anchor.

Drop anchor.

Use intermittent reverse thrust to slowly approach the pier.

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Mediterranean Mooring

Use intermittent forward thrust to maneuver to where you will drop anchor.

Drop anchor.

Use intermittent reverse thrust to slowly approach the pier.

Attach stern lines.

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Mooring to a Buoy

Using a permanent mooring is best when a boat is mostly at its homeport or when the boat is to be left unattended for long periods of time. A helix anchor or a mushroom

anchor is used for mooring buoys Concrete blocks can be used but that

should be many times heavier (around 2000 pounds) because they do not dig into the seabed and only their weight provides holding power.

Galvanized chain on the mooring should be about 1.5 times the depth.

The upper end of the chain is supported at the surface by a spherical or comical mooring buoy. Buoys are made of metal, wooden

spars or Styrofoam All strain should be transmitted

through this buoy using a chain or rod.

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Mooring to a Buoy

At the top of the mooring buoy is a line called a pendant made of manila or nylon and the same strength as the chain. It should be about 2.5 times the

height of the bow above the water.

An eye in the end of the pendant is run through the bow check at angles

The pendant should be covered with some type of protection to protect it from chafing.

The pickup buoy should have a ring or handle on top to aid in picking it up.