SBM Approach Heading

Port2 Harbor SBMs

SBM Approach Heading

Predicts the heading the ship will take on the SBM and the direction the hose will lie, and checks it against the recommended maneuver for SBM berths 20 to 24. All directions are °True.

Auto read automatically   Manual you type this   Check typical value, confirm for this ship. Tide times, heights and the stream rate come from the tide table.

Berth and time

Tide

Auto · Official tide tables 2026–27

Wind

Manual entry

Vessel and draft

~300,000 DWT
Draft Manual
UW volume— m³
Displacement— t

Predicted approach heading

---°T

Stream + wind resultant

Wind——
Stream——
Resultant——
Wind 0%Stream 0%

When wind or stream governs, and tug stop

    Stream through this tide leg

    Stream at approach time
    —
    Peak this leg
    —
    Tide position
    —

    Recommended maneuver · SBM berthing

    Recommended approach sector

    ---

    —

    Final COG
    —
    Area to be avoided
    Port side of the vessel
    Escape route
    To starboard, away from the hoses
    Tide, general direction
    Ebb 115°, flood 295°
    LOA limit
    No limit
    Sequence of approach
      All recommended approach angles

      Sudden wind change

      What happens if the wind shifts suddenly (squall, shamal) with the same stream.

      Hull and particulars · VLCC

      Mean draft
      —
      Trim
      —
      Freeboard
      —
      Windage area
      —
      Underwater side area
      —
      Ship particulars Check
      Typical 300,000 DWT VLCC values. Replace them with the ship's own data. Raise the stream drag coefficient when under-keel clearance is small.

      Heading through the tide

      Same wind and drafts, with the approach time moved from 2 h before to 8 h after the time entered. Where wind and stream push in opposite directions with similar strength, the heading can flip by about 180° within an hour. The table marks those times Balanced.

      • Predicted heading, 30 min steps
      • Stream rate, flood above zero and ebb below
      • Approach time

      How the heading is worked out

      • Wind direction is where the wind blows from. Stream direction is where the water flows toward. Everything is °True.
      • The stream follows a half sine through each tide leg. It is slack at the HW and LW times, plus the lag entered, and peaks mid-leg at the peak rate (the leg's tidal range times the factor entered, or the fixed value). Flood follows a low water and ebb follows a high water.
      • Wind force = ½ × 1.225 × wind drag coefficient × area × speed². The area is LOA × freeboard plus the superstructure area. Stream force = ½ × water density × stream drag coefficient × LBP × mean draft × speed².
      • The predicted heading puts the bow into the resultant of the two forces, the way a vessel weathervanes on a buoy. A deep-draft ship feels more stream force and a light ship feels more wind, so the draft changes the answer.
      • Underwater volume = LBP × beam × mean draft × block coefficient. The ship's hydrostatic tables give a better figure when they are to hand.
      • Tide: by default the page reads the high and low water times for the approach date from the Port2 Harbor Tide Tables 2026 (Final, Rev) and 2027, which cover 2026 and 2027. Switch Tide to Manual to use your own times.
      • Hose: the floating hose string (the hose has its own wind and stream resultant, separate from the ship, because it floats and is far lighter, so a different share of each force acts on it). is assumed to lie downstream of the buoy. Its direction is the resultant of wind drag on the part above water and stream drag on the part below water, using the hose diameter and submerged share entered. The angle to the approach track shows which side of the vessel the hose lies on.
      • Tugs: when the deeper of the forward and aft drafts is above the rule draft, the page shows a stern tug and a bow tug of the bollard pulls entered. This does not change the heading calculation.
      • Recommended maneuver: the approach sector comes from the Recommended Maneuvers booklet table for SBM berths 20 to 24. The page picks the row from the tide at the approach time (flood or ebb), the wind (taken as NW or SE, whichever it is closer to), the wind speed (20 kn or less, or above) and the arrival condition entered. The booklet has no row for a part-load tanker with wind and tide setting the same way; the page then says so and shows the predicted heading only.
      • Not included: waves, hawser load, thrusters and tugs, the rise in stream force at small under-keel clearance, and the ship's own yaw moment. Use it as a planning aid. The pilot and the mooring master decide the heading.