Technical Circular No: 029/2023

Subject : Ability to Override Engine or Shaft Power Limiting Devices.

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1. In order to comply with recent requirements aimed at reducing greenhouse gas emissions, some vessel operators have installed (or modified existing) engine power or shaft power limiters. In some cases, these limiters may reduce vessel maneuverability in a confined channel to an unacceptable level.

2. In this regard, Houston Pilots has issued Notice dated 01 September 2023 providing that in order to identify vessels that may pose additional risk to the channel due to a power limiting device, Houston Pilots Dispatch will, at the time an order for pilotage is taken, request the following information:

  • Is the vessel equipped with an engine or shaft power limiter?
  • If yes, is the limiter mechanical or software based?
  • If the vessel is equipped with a mechanical limiter, will it be removed or disabled prior to Pilot boarding?
  • If the vessel is equipped with a software-based limiter, will the ship's crew be able to override it immediately at the request of the Pilot?

Further, the attending Pilot for the vessel transit will confirm the information provided previously to Dispatch during the Master/Pilot exchange.

3. Attention is drawn to Section 2.04 of the Houston Pilots Navigation Safety Guidelines providing that:

a. The maneuvering revolutions and resultant speeds established for a vessel by her builders and designers must be posted and made available to the Pilot upon boarding. All vessels maneuvering in the Houston Ship Channel must be capable of promptly attaining the maneuvering RPMs as posted in the vessel's wheelhouse.

b. All vessels must be able to alter engine speed and direction promptly considering vessels of similar class and engine type. Vessels must be able to answer all engine and helm commands at all times while underway. Any load limiting or automatic acceleration limiting devices or software that would limit the speed of response to engine orders must be capable of being overridden immediately by the Master or Mate on watch from the bridge in case of an emergency.

c. Any vessel without the capacity to attain its posted RPMs in a timely fashion because of engine maintenance, engine break in requirements, or engine power limiting devices that cannot be overridden may, be restricted to daylight transit and/or additional Pilotage or tug requirements.

4. While the attending Pilot may request that the power limiter device be overridden, the Pilot may or may not access the additional power allowed depending on the conditions present during the transit.

5. Ship owners/ operators and masters to take note of above and are advised to identify and discuss any potential internal compliance issue related to overriding engine or shaft power limiters prior to their vessel’s arrival in Houston. 




This Technical Circular and the material contained in it is provided only for the purpose of supplying current information to the reader and not as an advice to be relied upon by any person. While we have taken utmost care to be as factual as possible, readers/ users are advised to verify the exact text and content of the Regulation from the original source/ issuing Authority.                              

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