Ground Tackle Anchoring and Mooring

1
Ground Tackle Anchoring and Mooring

• Quartermaster Requirement 8

2
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.

3
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.

4
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.

5
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 51 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 71 scope at
  low tide in six feet of water and a six foot tide
  comes in, your scope will be reduced to 3.51
• 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.

6
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.

7
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
  51 or less scope and have a smaller swinging
  radius than a boat with a combination chain and
  rope line.

8
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.

9
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.

10
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.

11
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.

12
Setting Two Anchors

• Drop anchor.

13
Setting Two Anchors

• Drop anchor.
• Use intermittent reverse thrust.

14
Setting Two Anchors

• Drop anchor.
• Use intermittent reverse thrust.
• Turn the boat and use forward thrust.
• KEEP THE RODE AWAY FROM THE PROP.

15
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.

16
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.

17
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.

18
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

19
Mediterranean Mooring

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

20
Mediterranean Mooring

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

21
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.

22
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.

23
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.

24
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.