33 CFR 401.3: Maximum vessel dimensions for transit
Last reviewed: October 14, 2026
This section sets maximum dimensions for vessels that transit. It limits overall length, extreme breadth, and height above water level, and bars protrusions beyond the hull. Some vessels slightly over the limits may apply to be considered for transit.
Applies toVessels that transit, as covered by this part.
What it says
Subject to paragraph (e), no vessel of more than 222.5 m in overall length or 23.8 m in extreme breadth may transit.
33 CFR 401.3(a)“Subject to paragraph (e) of this section, no vessel of more than 222.5 m in overall length or 23.8 m in extreme breadth shall transit.”
No vessel may transit if any part of it or anything on it extends more than 35.5 m above water level.
33 CFR 401.3(b)“No vessel shall transit if any part of the vessel or anything on the vessel extends more than 35.5 m above water level.”
No vessel may transit if any part of its bridges or anything on the vessel protrudes beyond the hull.
33 CFR 401.3(c)“No vessel shall transit if any part of its bridges or anything on the vessel protrudes beyond the hull.”
When a vessel is alongside a lock wall, its hull or superstructure must not extend beyond the limits of the lock wall, as illustrated in appendix I of this part.
33 CFR 401.3(d)“No vessel's hull or superstructure when alongside a lock wall shall extend beyond the limits of the lock wall, as illustrated in appendix I of this part.”
A vessel with a beam over 23.2 m but not over 23.8 m, within the limits in the block diagram in appendix I of this part, or a length over 222.5 m but not over 225.5 m, may apply to the Manager or Corporation and will be considered for transit under directions they issue.
33 CFR 401.3(e)“shall, on application to the Manager or Corporation, be considered for transit in accordance with directions issued by the Manager and Corporation.”
Vessels with beams greater than 23.20 m may be subject to transit restrictions and/or delays during periods of ice cover.
33 CFR 401.3(f)“Vessels with beams greater than 23.20 m may be subject to transit restrictions and/or delays during periods of ice cover.”
Common questions
What is the maximum vessel height allowed to transit?
No vessel may transit if any part of it or anything on it extends more than 35.5 m above water level.
“No vessel shall transit if any part of the vessel or anything on the vessel extends more than 35.5 m above water level.”
What is the maximum vessel length and breadth for transit?
Subject to paragraph (e), a vessel of more than 222.5 m in overall length or 23.8 m in extreme breadth may not transit.
“Subject to paragraph (e) of this section, no vessel of more than 222.5 m in overall length or 23.8 m in extreme breadth shall transit.”
Can wide vessels face delays in ice?
Yes. Vessels with beams greater than 23.20 m may be subject to transit restrictions and/or delays during periods of ice cover.
“Vessels with beams greater than 23.20 m may be subject to transit restrictions and/or delays during periods of ice cover.”
The text of 33 CFR 401.3
Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR
Maximum vessel dimensions
(a) Subject to paragraph (e) of this section, no vessel of more than 222.5 m in overall length or 23.8 m in extreme breadth shall transit.
(b) No vessel shall transit if any part of the vessel or anything on the vessel extends more than 35.5 m above water level.
(c) No vessel shall transit if any part of its bridges or anything on the vessel protrudes beyond the hull.
(d) No vessel's hull or superstructure when alongside a lock wall shall extend beyond the limits of the lock wall, as illustrated in appendix I of this part.
(e) A vessel having a beam width in excess of 23.2 m, but not more than 23.8 m, and having dimensions that do not exceed the limits set out in the block diagram in appendix I of this part or overall length in excess of 222.5 m, but not more than 225.5 m, shall, on application to the Manager or Corporation, be considered for transit in accordance with directions issued by the Manager and Corporation.
(f) Vessels with beams greater than 23.20 m may be subject to transit restrictions and/or delays during periods of ice cover.
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.