46 CFR 138.410: Conduct of external audits under TSMS
Last reviewed: October 14, 2026
This section explains how external audits of a towing safety management system (TSMS) are conducted. An auditor from a TPO must cover all TSMS elements, though sampling is allowed. The auditor must notify the local OCMI within 24 hours of a major non-conformity.
Applies toExternal audits of the TSMS of an owner or operating manager, conducted by an auditor from a TPO.
What it says
An auditor from a TPO must conduct external audits and cover all TSMS elements, but may use sampling of each element.
46 CFR 138.410(a)“External audits must be conducted by an auditor from a TPO and cover all elements of the TSMS requirements of this subchapter, but may be conducted on a sampling basis of each of those TSMS elements.”
External audits must be deep and broad enough to ensure the owner or operating manager effectively implemented its TSMS throughout all levels of the organization, including onboard its vessels.
46 CFR 138.410(b)“External audits must be of sufficient depth and breadth to ensure the owner or operating manager effectively implemented its TSMS throughout all levels of the organization, including onboard its vessels.”
The auditor must be given access to examine requested documentation, question personnel, examine vessel equipment, witness system testing, and observe personnel training, including drills, as necessary to verify TSMS effectiveness.
46 CFR 138.410(c)“The auditor must be provided access to examine any requested documentation, question personnel, examine vessel equipment, witness system testing, and observe personnel training, including drills, as necessary to verify TSMS effectiveness.”
The auditor may broaden the scope of the audit if the TSMS is incomplete or not effectively implemented, if conditions found are not consistent with the records, or if unsafe conditions are identified.
46 CFR 138.410(d)“The auditor may broaden the scope of the audit if:”
The auditor may verify compliance through objective evidence such as checklists, invoices, and reports, and may conduct a visual sampling onboard the vessels to check whether conditions are consistent with the records reviewed.
46 CFR 138.410(e)“may conduct a visual sampling onboard the vessels to determine whether or not the conditions onboard the vessel are consistent with the records reviewed.”
If an auditor identifies a major non-conformity during the audit, the auditor must notify the local OCMI within 24 hours, and must notify the owner or managing operator's designated representative in accordance with the TSMS applicable to the vessel.
46 CFR 138.410(f)“the auditor must notify the local Officer in Charge, Marine Inspection (OCMI) within 24 hours and the owner or managing operator's designated representative in accordance with the TSMS applicable to the vessel.”
Common questions
Who must conduct an external TSMS audit?
An auditor from a TPO must conduct external audits. The audit must cover all TSMS elements, but may sample each element.
“External audits must be conducted by an auditor from a TPO and cover all elements of the TSMS requirements of this subchapter”
When can an auditor broaden the scope of an external audit?
The auditor may broaden the scope if the TSMS is incomplete or not effectively implemented, if conditions found are not consistent with the records, or if unsafe conditions are identified.
“The auditor may broaden the scope of the audit if:”
How quickly must an auditor report a major non-conformity?
The auditor must notify the local OCMI within 24 hours. The auditor must also notify the owner or managing operator's designated representative in accordance with the TSMS applicable to the vessel.
“the auditor must notify the local Officer in Charge, Marine Inspection (OCMI) within 24 hours”
What evidence may an auditor review during an external audit?
The auditor may review objective evidence such as checklists, invoices, and reports. The auditor may also conduct a visual sampling onboard the vessels.
“through a review of objective evidence such as checklists, invoices, and reports”
The text of 46 CFR 138.410
Electronic Code of Federal Regulations (eCFR), current as of April 16, 2026 · Read it on eCFR
Conduct of external audits
(a) External audits must be conducted by an auditor from a TPO and cover all elements of the TSMS requirements of this subchapter, but may be conducted on a sampling basis of each of those TSMS elements.
(b) External audits must be of sufficient depth and breadth to ensure the owner or operating manager effectively implemented its TSMS throughout all levels of the organization, including onboard its vessels.
(c) The auditor must be provided access to examine any requested documentation, question personnel, examine vessel equipment, witness system testing, and observe personnel training, including drills, as necessary to verify TSMS effectiveness.
(d) The auditor may broaden the scope of the audit if:
(1) The TSMS is incomplete or not effectively implemented;
(2) Conditions found are not consistent with the records; or
(3) Unsafe conditions are identified.
(e) The auditor may verify compliance with vessel standards and TSMS requirements through a review of objective evidence such as checklists, invoices, and reports, and may conduct a visual sampling onboard the vessels to determine whether or not the conditions onboard the vessel are consistent with the records reviewed.
(f) If an auditor identifies a major non-conformity during the course of the external audit, then the auditor must notify the local Officer in Charge, Marine Inspection (OCMI) within 24 hours and the owner or managing operator's designated representative in accordance with the TSMS applicable to the vessel.
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.