Regulations made simple
USCG & International Compass Requirements
Who needs a properly adjusted magnetic compass and a current deviation table, and how often it has to be done.
In plain English
- Most commercial vessels, including towing vessels under Subchapter M and ships of 1,600 gross tons and over, need a magnetic compass and a current deviation table or record.
- Rule of thumb: have your compass swung and a new deviation table issued at least every 2 years, and every 12 months if you transit the Panama Canal.
- Also re-swing after installing a compass, after dry-docking or structural work, when electronics near the compass change, or whenever it seems unreliable.
Quick Reference
| Rule | Applies to | What it requires | How often |
|---|---|---|---|
| 33 CFR 164.35 | Self-propelled vessels of 1,600 GT and over in U.S. navigable waters | Illuminated magnetic steering compass in a binnacle, plus a current deviation table, graph or compass comparison record | Keep current |
| 46 CFR Subchapter M (140.725(d), 140.635(a)(5)) | Towing vessels | Illuminated magnetic compass; deviations must be known to the master and navigator. Inspectors typically expect a current deviation record. | Keep current |
| SOLAS V/19 | All ships on international voyages | A properly adjusted standard magnetic compass; a spare compass on ships of 150 GT and over | Every 2 years + events |
| IMO Res. A.382(X) | All ships | Compass properly compensated; table of residual deviations kept near the compass at all times | Keep current |
| ISO 25862:2019 | Ships built to ISO standards | Swing and adjust the compass | Every 2 years + after dry dock |
| Panama Canal (OP Notice to Shipping N-1-2022, sec. 4.k, p. 30) | Vessels of 150 GT and over | Residual deviation under 7°, verified by a recognized calibration authority with a new deviation table | Every 12 months |
| ABS Guide (Bridge Design & Navigation Equipment) | ABS-classed vessels | Magnetic compass complying with IMO A.382(X) | Per IMO |
Your Deviation Table
Swung, adjusted and documented
We adjust your compass at the dock, in any weather. Every adjustment is calibrated against a gyroscope, and you receive a deviation table signed by a certified compass adjuster, ready for your inspector, surveyor or the Canal.
Deviation Card
| Ship’s head | Deviation | Ship’s head | Deviation |
|---|---|---|---|
| 000° | 1° E | 180° | 1° W |
| 045° | 2° E | 225° | 1° W |
| 090° | 1° E | 270° | 0° |
| 135° | 0° | 315° | 1° E |
Sample for illustration only
The Regulations in Full
SOLAS Chapter V, Regulation 19 & Annex 13
SOLAS V/19.2.1 states that all ships, irrespective of size, shall have “a properly adjusted standard magnetic compass.” Regulation 19 also requires all vessels of 150 gross tons and over to carry a spare magnetic compass.
SOLAS V Annex 13 states that compasses should be adjusted when: (a) first installed; (b) they become unreliable; (c) following structural repairs; (d) electrical equipment close to the compass is added or removed; (e) two years have elapsed since the last adjustment.
IMO Resolution A.382(X)
All ships must be fitted with a magnetic compass. Each compass should be “properly compensated” and the table of residual deviations must be “available on board in the vicinity of the compass at all times.”
Annex II contains the accepted performance standards for compasses and the installation requirements, including minimum distances between the compass and sources of magnetic interference such as structure and electronic equipment.
ISO 25862:2019 (formerly ISO 2269)
Magnetic compasses shall be swung and adjusted no less than every two years, as well as after dry-docking and following any significant structural work.
ABS Guide for Bridge Design & Navigation Equipment
A magnetic compass must be provided and must comply with IMO A.382(X).
Panama Canal Vessel Requirements
Panama Canal Vessel Requirements (OP Notice to Shipping N-1-2022, section 4.k on p. 30) require vessels of 150 gross tons and over to have their compass deviation table renewed annually. Residual deviation of the magnetic compass must be less than 7°, verified by a “recognized calibration authority, and an accurate deviation table issued, within the previous 12-month period.”
33 CFR 164.35 (U.S.)
All self-propelled vessels of 1,600 or more gross tons operating in the navigable waters of the United States must have “an illuminated magnetic steering compass, mounted in a binnacle” and “a current magnetic compass deviation table or graph or compass comparison record.”
46 CFR Subchapter M: Towing Vessels (U.S.)
46 CFR 140.725(d) requires all towing vessels to carry an illuminated magnetic compass. Section 140.635(a)(5) states that compass deviations must be known to the navigator and the master of the towing vessel, which makes a compass adjustment necessary.
Towing vessels over 12 meters (39.4 ft) in length are also subject to 33 CFR 164.72. Most Subchapter M inspections interpret these rules as requiring a “current compass deviation record,” as described in 33 CFR 164.35.
A vessel that tows exclusively on the Western Rivers may use a swing meter instead of a magnetic compass.
This page is a general summary for reference. Always confirm the current rules with the regulation itself, your Coast Guard inspector, third-party organization or class society.
Due for an inspection?
Book a dockside compass swing and get a current deviation table.