TVIB News Subchapter M Updates

USCG Now Accepts Aluminum Flammable-Liquid Storage Cabinets on Weather Decks for Subchapter M Towing Vessels

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What Owners, Operators, and Crews Need to Know

Published: December 12, 2025

The U.S. Coast Guard has released new guidance that directly impacts towing vessel operators subject to 46 CFR Subchapter M. Aluminum flammable-liquid storage cabinets may now be accepted on weather decks of Inspected Towing Vessels (ITVs) provided they meet specific construction and installation criteria.

 

** This policy does not apply to vessels subject to SOLAS requirements. **

 

USCG’s New Position: Aluminum Cabinets May Be Accepted as an Equivalent

Under 46 CFR §136.115 (a), the Coast Guard may approve alternatives that provide an equivalent level of safety. After reviewing performance, safety measures, and vessel applications, the USCG has determined that properly constructed aluminum cabinets can meet the intent of the fire-protection requirements when installed on weather decks.

The policy acknowledges that:

  • Aluminum has lower fire-resistance properties than steel,
  • But additional design and placement measures can offset this difference,
  • While also solving the corrosion and durability problems associated with steel cabinets exposed to the elements.

 

Key Requirements: What an Aluminum Storage Cabinet Must Have

To qualify, aluminum flammable-liquid storage cabinets used on weather decks must meet all criteria in Enclosure (1) of the policy. Highlights include:

Construction Requirements

  • Minimum ¼-inch aluminum for frame and shell
  • Fully welded construction
  • Maximum volume of 30 cubic feet
  • Raised door sill (≥2 inches) to contain spills
  • Latch-equipped doors
  • Permanent marking:
    “FLAMMABLE – KEEP FIRE AWAY”
    (contrasting color, letters ≥2 inches tall)

 

Location Requirements

  • Positioned as far as practicable from machinery spaces, exhaust outlets, and escape routes
  • Stowed away from ignition sources

 

Operational and Safety Requirements

  • Secured to the vessel per 46 CFR §142.225
  • A 40-B portable fire extinguisher located within a 30-ft travel distance
  • Contents limited to the minimum amounts necessary for vessel operations, not exceeding 120 gallons per cabinet
  • Cabinet must be repaired or replaced if deemed unserviceable by the local OCMI

 

Questions?

The Coast Guard encourages operators to reach out with questions regarding this policy:

The full policy letter is available @ U.S. Coast Guard Policy Letter 05-25 – Acceptance of Aluminum Flammable Liquid Storage Cabinets

TVIB FAQ – What is a TPO?

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This FAQ is designed to provide concise answers to common questions about Third Party Organizations (TPOs) and their role under 46 CFR Subchapter M. It serves as a guide for operators, auditors, and other stakeholders seeking to better understand compliance requirements and the benefits of working with a TPO.

For comprehensive answers and guidance, visit the FAQ section on our website: TVIB FAQ. Use the search function with the term “TPO” or navigate to 46 CFR Part 139 for relevant details.

TVIB FAQ – From Paper to Digital: NVIC 01-16 CH-3 – Chart & Publication Carriage Equivalencies for Inland Towing Vessels 

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What must mariners know about NVIC 01-16 (Change 3): Equivalency Determination for Chart and Publication Carriage Requirements?

In this FAQ, TVIB explains the equivalency options provided under NVIC 01-16 (Change 3) for meeting chart and publication carriage requirements.

This FAQ also consolidates the key requirements and clarifications that are not directly outlined in Subchapter M.

Take a few minutes to review the full FAQ to ensure your vessels remain in compliance with current Coast Guard guidance.

Find Detailed Guidance in Our FAQ
For comprehensive answers and guidance, visit the FAQ section on our website: TVIB FAQ. Use the search function with the term “NVIC 01-16” or navigate to 46 CFR Part 140 for chart and publication carriage requirements.