Pier Wall Inspection (PWI) Overview

The Pier Wall Inspection operation is a technique that can be used to visually inspect or search a pier wall structure. The purpose for this procedure is to maximize the chances of success and ensure that the entire pier is systematically inspected so there is no question that the entire pier has been completely inspected or searched.

The recommendations for this SOP come from some of the world's leading experts in the field and have been formulated after many hours of field experience. However, they should be considered a starting point since every possible scenario cannot be anticipated. Be prepared to make adjustments and fine tune the settings to adapt these recommendations to your specific circumstances and environment.

General Concept

The Pier Wall Inspection consists of navigating transects or passes parallel to the pier while observing the pier visually or with sonar. Horizontal passes are recommended over vertical passes because placing waypoints for vertical passes is more complicated.

Applicability

The Pier Wall Inspection is applicable to solid wall piers, such as concrete or sheet piling piers. Piers that consist of pilings only should be searched using the Piling Pier Inspection Standard Operating Procedure.

Prerequisites

Participants in a Pier Wall Inspection should be familiar with operating a VideoRay Defender running the Greensea Workspace control system. For more information about these products, see the Education Resources Library.

Searching for Threats or Hazards

If conducting a Pier Wall Inspection for the purpose of ensuring there are no threats or hazards in the pier area, it may be required to clear an area on the bottom in front of the pier. If the area of concern is close to the pier, a single pass focused on the bottom may be sufficient. If a larger area in front of the pier must be cleared, consider using the Wide Area Search Standard Operating Procedure to complete this part of the search.

There are two schools of thought about which part to search first, the pier or the bottom.

• If you will be operating from the pier, it is best to clear the pier first to avoid the ROV or tether from contacting a threat device on the pier while searching the bottom. However, since the pier will be inspected while the ROV is facing the pier, it is a good idea to clear the majority of the pier from the surface down, but switch to a pass to clear the bottom before completing the final transects of the pier. This can prevent accidentally contacting something on the bottom while navigating the ROV sideways to observe the pier.

• If you will be operating from a vessel, it makes more sense to clear the bottom before starting to search the pier. The tether is less likely to contact the pier when operating from a vessel, so clearing the bottom first does not represent a risk of accidentally contacting a threat on the pier.

Tether management is critical when searching for threats or when operating in an area that may have other vessel traffic. Exercise caution when managing the tether in such situations.