46 CFR 144.610: Ventilation on vessels over 65 feet

Last reviewed: October 14, 2026

This section covers ventilation on a vessel of more than 65 feet (19.8 meters) in length with overnight accommodations. Such a vessel must have a mechanical ventilation system. The exception is when a natural system will provide adequate ventilation in ordinary weather.

Applies toA vessel of more than 65 feet (19.8 meters) in length with overnight accommodations.

What it says

  1. A vessel of more than 65 feet (19.8 meters) in length with overnight accommodations must have a mechanical ventilation system.

    “A vessel of more than 65 feet (19.8 meters) in length with overnight accommodations must have a mechanical ventilation system”

  2. The vessel does not need a mechanical ventilation system if a natural system, such as opening windows, portholes, or doors, will provide adequate ventilation in ordinary weather.

    “unless a natural system, such as opening windows, portholes, or doors, will provide adequate ventilation in ordinary weather.”

Common questions

Does a vessel over 65 feet with overnight accommodations need mechanical ventilation?

Yes, it must have a mechanical ventilation system, unless a natural system will provide adequate ventilation in ordinary weather.

“must have a mechanical ventilation system unless a natural system, such as opening windows, portholes, or doors, will provide adequate ventilation in ordinary weather.”

Can opening windows or doors replace mechanical ventilation?

Yes, if a natural system such as opening windows, portholes, or doors will provide adequate ventilation in ordinary weather.

“a natural system, such as opening windows, portholes, or doors, will provide adequate ventilation in ordinary weather.”

The text of 46 CFR 144.610

Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR

Ventilation in a vessel more than 65 feet in length

A vessel of more than 65 feet (19.8 meters) in length with overnight accommodations must have a mechanical ventilation system unless a natural system, such as opening windows, portholes, or doors, will provide adequate ventilation in ordinary weather.

The plain-English explanation on this page was written with AI from the regulation text above and checked automatically before publishing: every quote appears in the text, every number comes from it, and a second model confirmed each statement adds nothing the text doesn't say. Regulation text current as of April 16, 2026. The regulation text governs. RegKnot is not affiliated with the U.S. Coast Guard.