Fueling Procedures and Pollution Prevention

TL;DR — Passengers must be off the vessel before taking on fuel with a flash point of 43.3 °C (110 °F) or lower; remote fuel shutoff stations must be marked in legible letters at least 1 inch high. Discharge containment requirements, fuel system construction standards, and transfer procedures are layered across 33 CFR and 46 CFR and are heavily tested on the OUPV/Master 100 GT written exam.

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What the Rule Says

Fueling with Passengers Aboard

The most directly tested rule in this topic is straightforward: a vessel must not take on fuel having a flash point of 43.3 °C (110 °F) or lower — gasoline being the named example — when passengers are on board. 46 CFR §185.350

This is an absolute prohibition. There is no exception for "brief" fueling stops, calm conditions, or any other circumstance. If passengers are aboard, low-flash-point fueling does not happen.

Remote Fuel Shutoff Valve Marking

Remote fuel shutoff stations must be marked in clearly legible letters at least 25 millimeters (1 inch) high. The marking must indicate the purpose of the valve and the direction of operation. 46 CFR §185.608 This requirement ensures that any crew member — or a first responder unfamiliar with the vessel — can locate and operate the shutoff quickly in an emergency.

Fuel Oil and Bulk Lubricating Oil Discharge Containment

Containment requirements under 33 CFR §155.320 are tiered by vessel size and construction date. 33 CFR §155.320

Ships of 300 GT or more, constructed after June 30, 1974 must have a fixed container or enclosed deck area under or around each fuel oil or bulk lubricating oil tank vent, overflow, and fill pipe:

• 300 GT or more but less than 1,600 GT: capacity of at least one-half barrel. 33 CFR §155.320
• 1,600 GT or more: capacity of at least one barrel. 33 CFR §155.320

Ships of 100 GT or more constructed before July 1, 1974, and ships of 100 GT or more but less than 300 GT constructed after June 30, 1974 must do one of the following:

1. Meet the one-half barrel fixed containment standard above; or 2. Equip each vent, overflow, and fill pipe during oil transfer operations with a portable container of at least 5 U.S. gallons capacity; or 3. If the fill fitting makes containment impractical, use an automatic back pressure shut-off nozzle. 33 CFR §155.320

Note that this section does not apply to fixed or floating drilling rigs or other platforms. 33 CFR §155.320

Transfer Procedures

The operator of a vessel with a capacity of 250 or more barrels of oil, hazardous material, or liquefied gas (as regulated in Table 4 of 46 CFR part 154) must provide written transfer procedures meeting the requirements of 33 CFR part 155 and part 156. Those procedures must cover transfers to or from the vessel and transfers from tank to tank within the vessel. 33 CFR §155.720

Pollution Prevention Equipment and Procedures — General Applicability

A vessel subject to 46 CFR Subchapter K must comply with the applicable design, equipment, personnel, procedures, and record requirements of 33 CFR parts 151, 155, and 156. 46 CFR §184.702 This cross-reference is important: it ties the vessel's certificate of inspection obligations directly to the oil transfer and pollution prevention regulations.

Fuel System Construction — Integral Tanks and Piping

Vent pipes. Each integral fuel tank must be fitted with a vent pipe connected to the highest point of the tank, terminating in a 180-degree bend on a weather deck, and fitted with a flame screen. 46 CFR §28.335 46 CFR §28.835 The 180-degree bend directs any fuel vapor discharge downward, away from ignition sources. For tanks not filled under pressure, the vent pipe net cross-sectional area must be at least 0.484 square inches (312.3 mm²). Where a tank is filled under pressure, the vent pipe area must be at least equal to the fill pipe area. 46 CFR §28.335

Fuel line materials. Except for outboard engines and portable bilge pumps, fuel lines must be seamless steel, annealed copper, nickel-copper, or copper-nickel, with a minimum wall thickness of 0.035 inch (0.9 mm). 46 CFR §28.335 46 CFR §28.835 Aluminum piping is acceptable on aluminum hull vessels only if installed outside the machinery space and at least Schedule 80 in thickness. 46 CFR §28.335

Nonmetallic flexible hose. Flexible nonmetallic hose is permitted but is strictly limited: no more than 30 inches (762 mm) in length; must be visible and easily accessible; must not penetrate a watertight bulkhead; must be fabricated with an inner tube and cover of synthetic rubber or suitable material reinforced with wire braid; must use corrosion-resistant compression fittings; and must be secured with two clamps at each end (clamps must not rely on spring tension and must be installed beyond the bead, flare, or over the serrations of the fitting). 46 CFR §28.335 46 CFR §28.835

Piping near high-heat sources. Supply piping conveying fuel oil or lubricating oil in close proximity to equipment with open flames or parts operating above 260 °C (500 °F) must be seamless steel. 46 CFR §28.835

Shutoff valves. A fuel line subject to internal head pressure from fuel in the tank must be fitted with a positive shutoff valve at the tank, operable from a safe location outside the space where the valve is located. 46 CFR §28.335 Under the more detailed requirements applicable to certain vessels, shutoff valves must be installed as close to each tank as practicable and as close to each fuel pump as practicable, and must be accessible at all times. The tank-side valve on a pressurized line must close against the flow and be capable of remote actuation from outside the space, suitably marked. 46 CFR §28.835

Test cocks. Test cocks must not be fitted to fuel oil tanks. 46 CFR §28.835

Drip pans. Oil piping drains, strainers, and other equipment subject to normal oil leakage must be fitted with drip pans or other means to prevent oil from draining into the bilge. 46 CFR §28.835

Portable fuel systems. Portable fuel systems — including portable tanks and related fuel lines and accessories — are prohibited except for use with outboard engines or portable bilge/fire pumps. 46 CFR §28.335 46 CFR §28.835

Fuel type restriction. Except for outboard engines, the use of fuel other than bunker C or diesel is prohibited. An installation using bunker C must comply with Subchapter F requirements. 46 CFR §28.335

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Why It Matters on the Exam

The OUPV and Master 100 GT written exams test this topic from several angles:

1. Passenger safety during fueling. The 43.3 °C / 110 °F flash point threshold and the absolute prohibition on fueling with passengers aboard are classic multiple-choice targets. Expect a scenario question: "You are preparing to fuel your 65-foot passenger vessel with gasoline. What must you do first?" The answer is: ensure all passengers are off the vessel. 46 CFR §185.350

2. Containment capacity thresholds. Examiners test whether you know the one-half barrel vs. one barrel distinction (300–1,599 GT vs. 1,600+ GT) and the alternative compliance options for smaller or older vessels (5-gallon portable container or automatic back-pressure shutoff nozzle). 33 CFR §155.320

3. Transfer procedure applicability. The 250-barrel threshold for required written transfer procedures is a specific number that appears in exam questions. 33 CFR §155.720

4. Fuel system hardware details. The 30-inch maximum length for nonmetallic flexible hose, the two-clamp requirement, the 180-degree vent termination with flame screen, and the 0.035-inch minimum wall thickness are all testable specifics. 46 CFR §28.335 46 CFR §28.835

5. Shutoff valve marking. The 1-inch (25 mm) minimum letter height for remote shutoff station markings is a precise number that distinguishes a correct answer from a distractor. 46 CFR §185.608

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Common Pitfalls

Pitfall 1: Confusing the flash point threshold. The prohibition applies to fuels with a flash point of 43.3 °C (110 °F) or lower. Gasoline is the named example. Diesel fuel has a higher flash point and is not subject to this passenger-prohibition rule. Do not invert the threshold.

Pitfall 2: Misremembering containment capacities. The one-half barrel / one barrel split is at 1,600 GT, not 1,000 GT or some other round number. The alternative 5-gallon portable container option applies only to the smaller/older vessel category — it is not available to a post-1974 vessel of 300 GT or more.

Pitfall 3: Assuming portable fuel tanks are always prohibited. They are prohibited as a general rule, but there is a specific exception for outboard engines and portable bilge/fire pumps. 46 CFR §28.335 46 CFR §28.835 Exam distractors will omit this exception.

Pitfall 4: Overlooking the 250-barrel transfer procedure threshold. This applies to oil, hazardous material, or liquefied gas. A vessel carrying only 200 barrels of oil is below the threshold; a vessel carrying 250 barrels is at or above it and must have written procedures. 33 CFR §155.720

Pitfall 5: Forgetting that shutoff valve marking requirements specify both content and size. The marking must state the purpose of the valve and the direction of operation, in letters at least 1 inch high. An answer that mentions only size or only purpose is incomplete. 46 CFR §185.608

Pitfall 6: Applying the wrong CFR part. 46 CFR §28.335 applies to commercial fishing vessels and similar vessels under Subchapter C. 46 CFR §28.835 applies to a different vessel category under the same subchapter. 46 CFR §185.350 and §185.608 apply to small passenger vessels under Subchapter T. Know which set of rules governs the vessel type in the exam scenario.

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Quick Check

Q1: At what flash point threshold are passengers required to be off the vessel before fueling begins?

Passengers must be off the vessel before taking on any fuel with a flash point of 43.3 °C (110 °F) or lower. 46 CFR §185.350

Q2: A 900 GT vessel constructed in 1980 has fuel oil fill pipes on deck. What fixed containment capacity is required at each vent, overflow, and fill pipe?

At least one-half barrel. The vessel is 300 GT or more but less than 1,600 GT, constructed after June 30, 1974, so the one-half barrel fixed containment requirement applies. 33 CFR §155.320

Q3: What is the maximum permitted length for a nonmetallic flexible fuel hose in a fuel supply line?

No more than 30 inches (762 mm). 46 CFR §28.335 46 CFR §28.835

Q4: At what vessel capacity (in barrels) does an operator become required to provide written oil transfer procedures?

250 barrels or more of oil, hazardous material, or liquefied gas. 33 CFR §155.720

Q5: What minimum letter height is required for markings on remote fuel shutoff stations, and what information must the marking convey?

Letters must be at least 25 millimeters (1 inch) high and must indicate the purpose of the valve and the direction of operation. 46 CFR §185.608

Q6: A vessel's integral fuel tank vent pipe terminates on the weather deck. What two features are required at the termination point?

A 180-degree bend and a flame screen. 46 CFR §28.335 46 CFR §28.835

Q7: A 150 GT vessel built in 1968 is conducting an oil transfer. Fixed containment is not installed. What two alternative compliance options are available?

(1) Equip each vent, overflow, and fill pipe with a portable container of at least 5 U.S. gallons capacity during the transfer; or (2) use an automatic back pressure shut-off nozzle if containment at the fill fitting is impractical. 33 CFR §155.320