Subchapter M: TSMS option vs. Coast Guard option
By Captain Karynn Marchal, Master Unlimited. Last reviewed: October 23, 2026.
A towing vessel documents compliance for its Certificate of Inspection in one of two ways under 46 CFR 136.130. Under the Coast Guard option, the Coast Guard conducts the inspections. Under the TSMS option, the company uses a Towing Safety Management System, with surveys and audits described in 46 CFR parts 137 and 138. The Coast Guard still issues the COI either way, and the owner or managing operator chooses the option for each vessel on the application for inspection.
The two options
46 CFR 136.130(a) states the choice:
- The Coast Guard option, in which all inspections of the towing vessel are conducted by the Coast Guard, as discussed in 46 CFR 136.210 and parts 137 and 140 through 144.
- The TSMS option, as discussed in 46 CFR 136.210 and in parts 137 through 144.
Whichever option is chosen, the Coast Guard is responsible for issuing the towing vessel COI and may board the vessel at any time to verify compliance (46 CFR 136.130(b)). An owner on the Coast Guard option may use a management system, vessel operations manual, towing vessel record (TVR), or logbook to meet Subchapter M's recordkeeping requirements (46 CFR 136.130(c)). That paragraph does not require a third-party organization.
The choice is made per vessel. Different vessels in one fleet may use different options (46 CFR 136.130(d)). Changing options during the period of validity of an existing COI requires an application to the Officer in Charge, Marine Inspection (OCMI) for a new COI (46 CFR 136.130(e)).
What each option requires
| Coast Guard option | TSMS option | |
|---|---|---|
| Who inspects or surveys the vessel | The Coast Guard conducts the inspections (46 CFR 136.130(a)(1)). | The owner documents compliance with an external survey program or an internal survey program (46 CFR 137.202). |
| Annual check | An annual inspection within 3 months before or after the COI anniversary date (46 CFR 137.200). The owner contacts the OCMI to schedule it. No written application is required for that annual inspection. | External survey program: a surveyor from a third-party organization (TPO) surveys the vessel annually, within 3 months of the COI anniversary date (46 CFR 137.205). Internal survey program: the interval between successive surveys of any item does not exceed 1 year, unless otherwise prescribed (46 CFR 137.210(b)). |
| What goes with the COI application | Form CG-3752, plus the items in 46 CFR 136.210(a). | The same application, plus objective evidence that the owner or managing operator and the vessel comply with the TSMS requirements in part 138, and objective evidence that the vessel's structure, stability, and essential systems comply with Subchapter M for the intended route and service (46 CFR 136.210(b)). |
| Company system | Not required by 46 CFR 136.130(c). A management system or logbook may still be used for recordkeeping. | A TSMS whose functional requirements are listed in 46 CFR 138.215. A TPO issues the TSMS certificate when the organization is deemed in compliance (46 CFR 138.305(a)). |
Under the TSMS option, before the vessel's initial COI, the owner or managing operator must give the Coast Guard a survey report, as described in 46 CFR 137.215, showing that the vessel complies with the requirements of part 137 (46 CFR 137.202(a)). For re-issuance of the COI, the owner provides objective evidence of either the external survey program (46 CFR 137.205) or the internal survey program (46 CFR 137.210).
The TSMS certificate and its audits
A TSMS certificate is valid for 5 years from the date of issue, unless it is suspended, revoked, or rescinded (46 CFR 138.305(b)). A copy is kept on each towing vessel the certificate covers and at the shoreside office (46 CFR 138.305(f)).
Internal management audits are conducted annually, within 3 months of the anniversary date of the TSMS certificate (46 CFR 138.310(a)). The audit covers the TSMS throughout the organization, including audits of the towing vessels the TSMS applies to (46 CFR 138.310(b)). Results are kept for 5 years and made available to the Coast Guard on request (46 CFR 138.310(c)).
External audits are conducted through a TPO (46 CFR 138.315):
- An external management audit before the initial TSMS certificate, and again for renewals.
- A mid-period external management audit between the 27th and 33rd month of the certificate's period of validity.
- External vessel audits during the 5-year period of validity. Vessels are selected randomly and distributed as evenly as possible. Some portions require visiting each vessel at some point during those 5 years.
46 CFR 138.215 lists what a TSMS has to contain, including policies and procedures for safe operation and protection of the marine environment, lines of communication between shoreside and vessel personnel, accident and non-conformity reporting, emergency procedures, verification of vessel compliance, internal and external audits, and management review of audit reports.
Common questions
Does the Coast Guard still issue the COI if I use a TSMS?
Yes. 46 CFR 136.130(b) says the Coast Guard is responsible for issuing a towing vessel COI regardless of the option chosen, and may board the vessel at any time to verify compliance.
Can one company use the TSMS option on some boats and the Coast Guard option on others?
Yes. 46 CFR 136.130(d) says owners or managing operators may choose different options for the individual vessels within their fleets. The choice is specified on the application for inspection for each vessel.
How do I switch from one option to the other?
46 CFR 136.130(e): a request to change options during the period of validity of an existing COI must be accompanied by an application to the OCMI for a new COI. If the requirements for the new option are met, the OCMI issues a new COI.
How often is the Coast Guard inspection under the Coast Guard option?
46 CFR 137.200: a vessel on the Coast Guard inspection option must undergo an annual inspection within 3 months before or after the COI anniversary date. The owner contacts the cognizant OCMI to schedule it. No written application is required for that annual inspection.
How long is a TSMS certificate good for?
46 CFR 138.305(b): a TSMS certificate is valid for 5 years from the date of issue, unless suspended, revoked, or rescinded.
Disclaimer
This guide is a navigation aid, not legal advice or a Coast Guard determination. It summarizes the sections it cites and does not replace them. Where a section sends you to another section for a detail, that section controls. RegKnot is not affiliated with the U.S. Coast Guard. The regulation text governs.