Work out mooring line load instantly with clear inputs, formula shown and shareable results.
Mooring lines only share load in proportion to the cosine of their angle to the applied force, and never perfectly because of stretch and tension differences — an 85% sharing efficiency is a common allowance. Industry guidance keeps working load below about 55% of minimum breaking load.
Mooring load
load per line = total force / (lines x cos(angle) x sharing efficiency)
Marine results are planning estimates only. Verify against the vessel's approved stability booklet, loading manual, class society rules and applicable maritime regulations before loading or sailing.
Differences in line length, material and initial tension mean the tightest line takes far more than its nominal share, so an efficiency factor is applied.
It preserves margin against snap-back, wear, splice strength loss and dynamic surge loads, which can easily double a static tension.