New underwater noise notation

The underwater noise notation is based on the new ISO 17208 standards and defines three criteria curves: transit, quiet and research. It also includes a speed indication, e.g. ‘UWN-L(T20)’, which would mean that a vessel meets the underwater noise criteria in transit (T) at a speed of 20 knots.

LR’s Per Trøjgård Andersen, technical lead – engineering dynamics, commented: “This new notation will not only help shipowners to reduce underwater noise radiation in sensitive environments. It will also demonstrate a commitment to environmentally friendly practices, and even has the added benefit of potential discounts in port fees.”

Design phase help

In addition to testing and certifying vessels, LR will also work with shipowners during the design phase to predict and control the underwater noise emissions from vessels.

Increased focus is being placed on underwater noise emissions from vessels and this is creating the need for a means of controlling underwater noise radiation. New international standards and regulations are anticipated, which will restrict access to environmentally sensitive areas and limit the types of vessels calling at ports to only those complying with stringent noise level standards.

Several countries and ports have already introduced speed restrictions in sensitive areas. Some ports also offer discounts in port fees if the ship has an underwater noise notation that certifies compliance with a set of underwater noise limits.