3105F.2.1 Manual Procedure
Simplified calculations may be used to determine the mooring forces for barges with Favorable Site Conditions (see Table 31F-3-8) and no passing vessel effects (see Section 3105F.3.2), except if any of the following conditions exist (Figures 31F-5-2 and 31F-5-3).
- Mooring layout is significantly asymmetrical
- Horizontal mooring line angles (α) on bow and stern exceed 45 degrees
- Horizontal breast mooring line angles exceed 15 normal to the hull
- Horizontal spring mooring line angles exceed 10 degrees from a line parallel to the hull
- Vertical mooring line angles (θ) exceed 25 degrees
- Mooring lines for lateral loads not grouped at bow and stern
When the forces have been determined and the distance between the bow and stern mooring points is known, the yaw moment can be resolved into lateral loads at the bow and stern. The total environmental loads on a moored vessel are comprised of the lateral load at the vessel bow, the lateral load at the vessel stern and the longitudinal load. Line pretension loads must be added.
Four load cases shall be considered:
- Entire load is taken by mooring lines
- Entire load is taken by breasting structures
- Load is taken by combination of mooring lines and breasting structures
- Longitudinal load is taken only by spring lines