The process of selecting an anchorage and maneuvering a vessel requires thorough preparation, precise execution, and adherence to good seamanship. Mariners must carefully consider various environmental and operational factors to ensure safety and stability. Below is a detailed guide to anchorage selection, anchor dropping, anchorage checking, mooring, and alongside maneuvers.

Anchorage Selection

Before proceeding to anchor, it is crucial to evaluate the geographical characteristics of the area and understand how an anchored vessel behaves under various forces exerted by its anchors. Updated nautical charts, pilot books, and other navigational aids must be carefully reviewed. The following factors are critical in choosing a suitable anchorage:

  1. Sea Depth and Tidal Range
    • The depth of the sea and the height of the tide must be compatible with the vessel’s draught.
  2. Sea Floor Composition
    • High-quality seabeds like mud, clay, or sand offer secure holding. In contrast, rocky, shelly, or pebbly seabeds are low-quality and generally unsafe for anchoring.
  3. Anchorage Location
    • Whether the anchorage is within a protected gulf, bay, or harbor, or in an open bay, affects its suitability.
  4. Wind Conditions
    • Knowledge of prevailing wind directions and intensities is essential. In two-anchor mooring, the first anchor should be dropped on the side of the most prevalent wind.
  5. Currents and Tides
    • The direction, intensity, and tidal characteristics of currents must be accounted for when selecting an anchorage.
  6. Proximity to Hazards and Other Vessels
    • Ensure sufficient clearance from navigational dangers and other vessels to allow free movement around the anchoring point.
  7. Anchor Chain Length
    • The length of the anchor chain depends on all the above factors. Typically, the chain length should be three to four times the depth of the sea.

Approaching the Anchorage
Approach the anchorage at low speed, using visible landmarks like lights, masts, or chimneys as guides. An ideal approach involves aligning the bearing of one landmark with the variation of another for precise positioning.

Anchor Dropping

When dropping the anchor, the vessel should move consistently in one direction to prevent tangling of the anchor chain. Key considerations include:

  1. Selection of Anchor
    • In the northern hemisphere, the left anchor is often preferred to minimize chain entanglement when deploying a second anchor.
  2. Direction of Anchorage
    • The vessel should anchor opposite the direction of prevailing wind or current.
  3. Two-Anchor Anchorage
    • First drop the weather anchor, followed by the second. The distance between the anchors should equal the total chain length minus one chain length.
  4. Adjusting for Weather
    • In adverse weather conditions, additional chain length should be loosened for stability.

Anchorage Checking

After anchoring, the vessel’s position must be continuously monitored. Use visible landmarks and bearings to detect any shift in position. This ensures that the anchor remains secure and avoids dragging.

Mooring Techniques

During mooring, one or both anchors may be dropped. If both are used, they should be positioned at a small angle to prevent tangling during departure. The chain length should provide sufficient resistance against lateral wind, typically around four shackles.

Steps for Mooring:

  1. Dropping the External Anchor
    • Drop the external anchor slightly ahead, releasing one or two shackles while maneuvering the vessel into position.
  2. Using the Second Anchor
    • Drop the second anchor as the vessel turns towards the external anchor. Gradually loosen both chains to align the stern with the wharf.
  3. Adjusting Chains
    • Immediately loosen the chains by 4–6 meters to stabilize the vessel.
  4. Fastening Aft Cables
    • Secure the aft cables crosswise to bollards for stability. In strong winds, fasten both cables to the windward bollard to prevent excessive strain on the leeward cables.

This method, commonly known as the “Mediterranean moor,” is widely used in specific anchorage scenarios.

Alongside Maneuvers

The technique for approaching a pier depends on the vessel’s design and operational characteristics. The following guidelines apply under calm conditions:

Single-Screw Vessel

  1. Port Side Approach
    • Approach the pier at a 15°–20° angle, directing the bow slightly ahead of the rotation point (bridge). Use astern propulsion to align the stern with the pier and secure the cables.
  2. Starboard Side Approach
    • Approach the pier at a smaller angle (10°–15°). As the bow nears the pier, rudder hard to port and ahead propulsion will deflect the bow away while the stern aligns with the pier.

Twin-Screw Vessel

  1. Controlled Speed
    • Maintain sufficient speed for effective rudder control but reduce speed for precise maneuvering.
  2. External Propeller Use
    • During the final approach, only the external propeller should be used to control the stern’s movement. This minimizes wake interference with the pier.
  3. Angle of Approach
    • Approach at a 15°–25° angle, ensuring the rotation point aligns with the pier. Stop the engines in time to stabilize the vessel and fasten the cables securely.

Key Considerations for Windy Conditions

  1. Leeway
    • Account for the vessel’s tendency to drift under wind pressure when reducing speed or stopping engines.
  2. Wind from Wharf Side
    • Maneuvering becomes more challenging when the wind blows from the side of the wharf, especially with a single propeller.
  3. Wind Parallel to Wharf
    • If the wind blows parallel from the stern, it facilitates the maneuver by stabilizing the vessel’s position.