SOLAS II-1/3-4 • MSC.35(63) • MSC.549(108) • MSC.1/Circ.1691 • Tow Resistance • Towline • Chock • Strongpoint • Tug Pull
Emergency Towing Arrangement, Towline Tension, Chock SWL & Tug Bollard Pull Tool
Screen an emergency tow from steady resistance through dynamic line tension, towing-gear weak link and available tug force, then use Advanced for environmental resistance, statutory ETA strength, deployment, multiple scenarios, pennant/chafing checks and Emergency Towing Booklet readiness.
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Need much more depth? Click Advanced above.Advanced adds projected-area resistance, wind/current/wave scenarios, statutory ETA strength, tanker vs 2028 non-tanker rules, lead-angle gates, pennant/chafing length, multiple tugs, deployment timing and full emergency-towing readiness.Fast10 primary inputs
Core answerLine tension + weak link + tug pull
VisualLoad path + tug-force charts
Single Emergency Tow
Use a salvage-master, model-test, CFD, sea-trial or otherwise credible steady tow resistance if available. Simple mode does not infer resistance from vessel geometry.
kN before dynamic amplification.
degrees from horizontal.
kN.
% of MBL.
tonnes-force.
% after sea-state / tow-speed derating.
Regulatory & Vessel Basis
t.
%.
min where no automatic ETA timing applies.
Automatic statutory screen: tanker ETA uses 1,000 kN working strength from 20,000 to below 50,000 DWT and 2,000 kN at 50,000 DWT and above. New non-tankers ≥20,000 GT constructed from 1 January 2028 use the EN-based MSC.1/Circ.1691 tiers. This check is separate from predicted casualty tow load.
Vessel Geometry & Environmental Tow Resistance
m².
m².
kN. 0 uses model.
Advanced Tow Scenario Register
0° is ahead, 90° beam, 180° following. Scenario names are not sent through Tool Data.
| Scenario | Speed kn | Wind kn | Wind ° | Current kn | Current ° | Wave add % | DAF |
|---|
Towline, Chock, Strongpoint & Loose Gear
% MBL.
degrees each side.
m.
m.
m.
Tug Bollard Pull & Available Tow Force
tf.
%.
%.
%.
Deployment & Emergency Towing Booklet Readiness
min.
Optional ETA Upgrade / Towability Budget
Engineering limitation: emergency towing loads depend strongly on heading, yaw, sea state, wave encounter, tow speed, current, tug position, towline stiffness/catenary, shock load, hydrodynamic interaction and casualty condition. This tool does not replace a salvage master, ship-specific towing analysis, class/flag-approved ETA design, certified bollard-pull data, approved shipboard SWLs, manufacturer limits or the Emergency Towing Booklet.