21/08/2026
Term of the Week: UWILD (Underwater Inspection in Lieu of Drydocking)
Every classed vessel or floating offshore asset is required to undergo periodic hull surveys to verify its structural integrity and continued compliance with Class requirements. A UWILD, or Underwater Inspection in Lieu of Drydocking, allows certain Class surveys to be carried out while the asset remains afloat, subject to approval by the relevant Classification Society and provided all applicable survey requirements are met.
For many FPSOs, FSOs, semi-submersibles and other permanently or long-term moored offshore assets, a UWILD can significantly reduce operational disruption by avoiding the time, cost and logistical challenges associated with drydocking. In some cases, it is the most practical way to maintain Class compliance while keeping the asset in service.
APEX AIS provides topside support for UWILD programmes through comprehensive structural integrity inspections, including General Visual Inspection (GVI), Close Visual Inspection (CVI) and a range of Non-Destructive Testing (NDT) methods on critical structural components.
Inspection scopes typically include, where applicable, jack-up legs and chords, leg guides and jacking systems, preload tanks and associated hull structure, leg well structures, as well as the main hull and deck structures.
The underwater inspection scope is performed by an appropriately qualified and certified commercial diving contractor in accordance with the applicable Class requirements. Working collaboratively, this integrated approach provides owners and Classification Societies with a comprehensive assessment of the asset's structural condition, both above and below the waterline.
A successful UWILD is not simply about inspecting steel beneath the waterline. It is about providing the evidence that owners, operators and Classification Societies need to make informed decisions about the continued integrity of the asset.
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