Weather-Dependent Container Lashing, Stack Weight & Securing Margin Tool
Weather-Dependent Lashing • Forecast Hs • Approved Reduction Factor • Stack Weight • Rods • Twistlocks • Racking • 2026 PSC CIC
Weather-Dependent Container Lashing, Stack Weight & Securing Margin Tool
Use an approved weather-dependent acceleration reduction only when its voyage and forecast conditions are satisfied. Simple converts the approved factor into a stack-weight and securing-margin decision. Advanced adds tier-by-tier transverse force, overturning, uplift, rod and twistlock demand, racking, corner-post compression, unrestricted comparison and re-stow economics.
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Need much more depth? Click Advanced above.Advanced separates acceleration, wind, overturning, lashing rods, twistlocks, racking and corner-post compression instead of scaling one approved utilization number.Fast10 primary inputs
Core answerCan the weather factor actually be used?
OutputStack-weight + securing margin
Fast Weather-Dependent Stack Screen
The reduction factor must come from the vessel's approved class/CSM/lashing-software basis. This calculator does not derive a class factor from wave height.
m. DNV-style mode rounds upward to the next 0.5 m for the eligibility screen.
m from approved weather-dependent lashing condition.
1.00 = unrestricted. DNV short-voyage mode flags factors below 0.30.
hours.
hours covered by the selected forecast.
t.
t. Structural / container / hatch-cover / CSM cap that weather reduction may not exceed.
% from approved CSM/lashing-software calculation for the current stack.
Approved Weather / Route Basis
m.
m.
h.
h.
g from approved acceleration/lashing basis.
g. Upward phase reduces apparent restoring weight.
Approved bay/deck/GM/position basis only.
kN/m² on exposed side area.
Use 1.00 unless approved basis permits another value.
Eligibility logic: in DNV-style short-voyage mode, the calculator rounds forecast Hs upward to the next 0.5 m, requires voyage duration ≤72 h, forecast coverage ≥ voyage duration, Hs within the entered approved ceiling, factor ≥0.30 and an approved weather-dependent basis. If any condition fails, the usable acceleration factor automatically becomes 1.00.
Stack Geometry & Securing Assumptions
m between transverse container sides.
%. Remaining uplift assigned to two windward twistlocks in this transparent screen.
% of entered rod MSL.
%.
%.
%.
%.
t. Structural/container/CSM cap independent of weather reduction.
Rows run bottom tier to top tier. Securing values in each row are treated as the securing available at the interface immediately below that tier. This is a transparent 2D screen, not a class 3D container-stack solver.
| Tier | Gross t | Height m | Wind area m² | Rods | Rod MSL kN | Rod angle ° | Twist tension kN/corner | Twist shear kN/corner | Racking kN/end | Corner comp kN/corner |
|---|
Operational & Commercial Inputs
moves for this port/short-voyage decision.
Selected currency/t of additional cargo contribution.
Weather-Dependent Lashing & 2026 PSC Readiness
Container-lashing screening only: this tool is not an approved Cargo Securing Manual calculation, StowLash3D or other class-approved lashing software, finite-element container model, container structural certification, twistlock stiffness model, lashing-bridge analysis or authorization to sail under reduced weather assumptions. Final stowage must be checked with the vessel's approved CSM/lashing software, class requirements and the Master's judgment.