HomeNew ULCS Wind-Tunnel Tests Find Port Structures Can Cut Mean Crosswind Loads 30–45%, But Extreme Loads Do Not Fall Proportionally

New ULCS Wind-Tunnel Tests Find Port Structures Can Cut Mean Crosswind Loads 30–45%, But Extreme Loads Do Not Fall Proportionally

September 23, 2026

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New boundary-layer wind-tunnel research into ultra-large container ships has found that surrounding port infrastructure can substantially reduce average aerodynamic loads on a moored vessel without producing an equivalent reduction in its extreme response. The 53-page study, posted to SSRN in September, tested empty, intermediate and fully loaded ULCS configurations using six-component force measurements and surface-pressure measurements in idealized harbor environments. None of the empirical wind-load formulations examined consistently reproduced every measured force and moment component. Port structures reduced mean transverse loading by as much as approximately 30–45% relative to an empty-quay environment in some tested configurations, but the researchers found that extreme response did not fall proportionally. A modeled storage-tank terminal even amplified low-frequency yaw-moment variance at selected wind directions while reducing other load components.

ULCS Wind-Tunnel Research · September 2026

The Port Is Part of the Aerodynamics

Buildings, container stacks and terminal structures do more than block wind. The experiments show that they can reshape the magnitude, direction and frequency content of aerodynamic loads acting on a moored mega-ship.

Mean Transverse Loading ↓ 30–45% Maximum reduction reported in some tested harbor configurations
Compared with the study's empty-quay environment, surrounding infrastructure substantially reduced average crosswind loading in selected cases.
Extreme Response ≠ The reduction did not scale proportionally
A strong reduction in average aerodynamic force cannot automatically be applied as the same percentage reduction to extreme response.
Port Infrastructure Behaved Like an Aerodynamic Filter
Incoming Wind Boundary-Layer Flow
Wind approaches the berth with direction, turbulence and frequency characteristics.
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Harbor Geometry Structures Reshape the Flow
Buildings, tanks and stacked containers alter shelter, turbulence and spatial pressure distribution around the ship.
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Vessel Response Forces + Moments Change
The resulting transverse force, longitudinal force and yawing moment depend on more than one universal shielding factor.
Empirical Models No formulation matched every load component
The empirical approaches tested did not consistently reproduce the complete set of wind-tunnel measurements.
Ship Loading Configuration controlled overall load magnitude
Empty, intermediate and fully loaded container configurations produced different aerodynamic loading levels.
Tank Terminal Shelter did not mean quieter yaw response
At selected wind directions, the modeled storage-tank terminal increased low-frequency yaw-moment variance even while reducing other loads.
Do not read 30–45% as a universal port shielding factor. The study found that the effect depended on harbor geometry, wind direction, frequency and vessel loading condition.
Experimental Design · Results · Engineering Context

What the Researchers Actually Tested

The experiments varied both the ship itself and the environment around it, allowing the team to separate changes in overall aerodynamic magnitude from changes created by the port.

Scroll sideways for the complete research board ← →
Research Element Test / Finding What Changed What the Result Shows Important Limit
Ship Loading Condition 3 CONFIGURATIONS Empty · Intermediate · Full Container-stack configuration changed the ship's exposed geometry and windage. Loading condition primarily governed the overall magnitude of aerodynamic loading. Results from one loading configuration should not automatically be transferred to another.
Measurement System PHYSICAL TESTING 6-Component Force Balance Forces and moments were measured together with surface-pressure measurements. The researchers could examine not only total load but how the pressure field and moment response changed. These are controlled wind-tunnel environments, not full-scale measurements from every possible port geometry.
Port Infrastructure SHIELDING + REDISTRIBUTION Up to 30–45% Mean Reduction Idealized harbor structures altered the flow around the moored vessel. Mean transverse loading could fall substantially compared with an empty-quay environment. The 30–45% figure represents maximum reductions in tested configurations, not a universal harbor correction.
Extreme Response NON-PROPORTIONAL Mean ≠ Extreme Infrastructure changed turbulence, spectral energy and force-moment relationships. A lower mean force did not translate into an equally large reduction in extreme response. Applying a simple shielding percentage to both average and extreme design loads would miss this behavior.
Storage-Tank Terminal DIRECTION-SENSITIVE Yaw Variance Increased Tank geometry altered low-frequency flow structures at selected wind directions. The same infrastructure could reduce certain force components while increasing yaw-moment variability. The paper does not show that tank terminals generally increase yaw loads. The effect occurred at selected tested directions.
The Older Assumption Ship + Wind Coefficient
Traditional empirical methods generally represent vessel wind loading with coefficients developed from simpler ship geometries and comparatively open conditions.
The Research Direction Ship + Loading + Wind + Harbor Geometry + Frequency
The new work indicates that realistic port structures can change both the size of the load and the way aerodynamic energy is distributed across direction, location and frequency.
Ship Universe ULCS Wind Scenario Tool

Port Shielding vs. Mean Wind Load

Test how wind speed and a user-selected infrastructure shielding assumption change mean transverse load while keeping extreme response separate.

kN
Scenario input. This is not a load reported for the test vessel.
m/s
m/s
%
The study reported reductions up to roughly 30–45% in selected tested configurations.
Same Ship · No Port Shielding 1,778 kN Reference mean load scaled to the scenario wind speed.
Mean Load With Selected Shielding 1,778 kN Mean-load scenario after applying the selected infrastructure reduction.
Mean Load Removed 0 kN Difference between the open-quay and selected mean-load scenarios.
Mean Transverse Load Comparison
Empty Quay
1,778 kN
Port Scenario
1,778 kN
Extreme Load Warning Do Not Copy the Mean Reduction
A 30% or 45% reduction in mean transverse load does not mean the extreme response should automatically be reduced by 30% or 45%. The study found that extreme attenuation was not proportional, and harbor geometry could alter low-frequency yaw behavior.
Scenario tool only: aerodynamic force is scaled here with the square of wind-speed ratio while the infrastructure percentage is applied only to mean transverse loading. The September study does not provide a universal 30% or 45% shielding coefficient for real terminals, and this tool does not calculate mooring-line loads, bollard loads, vessel motions or extreme gust response.
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