USCG Barge Supervisor cheat sheet

Loading rate is controlled by shore pump capacity and barge vent capacity; the lower of the two governs the safe transfer rate.

Line-up before transfer: verify valve alignment, blank flanges, hose/loading arm condition, and that all cargo goes to the intended tank.

Topping off: reduce rate to roughly 10-20% of full rate when tank is about 80-90% full to allow for line and tank drain-down.

Displacement/void space check: expected change in tank volume must match observed cargo transferred; mismatch indicates a valve, line, or gauge error.

Vapor return line must be connected and open when loading volatile cargo to prevent overpressure and to control emissions.

Emergency shutdown (ESD) test and deadman/remote shutdown must be verified functional before starting transfer.

Pre-transfer conference covers: product, quantity, rate, max pressure, communications, ESD, spill response, and mooring plan.

Drain and strip cargo lines after transfer; line contents count toward quantity and must be accounted for in the Bill of Lading.

Flash point is the lowest temperature at which a liquid gives off enough vapor to ignite; below flash point, flammable range may exist in the tank ullage.

Flammable range (LEL-UEL) widens with temperature; a tank is safest when either too lean (below LEL) or too rich (above UEL).

Vapor density greater than air (most hydrocarbons) means vapors collect in low spaces, bilges, and along the water surface.

Specific gravity vs water determines whether a spill floats, sinks, or disperses; hydrocarbons typically float and spread.

Compatibility rule: never segregate cargoes that react (acids with caustics, oxidizers with organics) in adjacent tanks sharing a common vent or line.

SOUR/ H2S cargoes are toxic at low ppm; H2S is heavier than air and deadens smell at higher concentrations.

Static electricity: low-conductivity products (distillates) accumulate charge; bond and ground before and during transfer.

Cargo contamination risks: previous cargo residue, line cross-connection, and water/particulate ingress; verify tank cleanliness first.

Draft change (inches) = weight loaded (tons) x 12 / TPI (tons per inch immersion); TPI varies with waterplane area.

Trim = difference between forward and aft drafts; trim moment = weight x longitudinal distance from LCF; change in trim = trimming moment / MTC.

GM (metacentric height) = KM - KG; positive GM means stable, negative GM means tender/unstable.

Free surface effect reduces effective GM: FSC = (free surface moment) / displacement; minimize slack tanks to control it.

List = transverse moment / (displacement x GM); a small GM amplifies list from off-center weight.

Block coefficient and deck load limits: never exceed the barge's rated deck load or tank fill limits stated in the load line/stability book.

Load line (Plimsoll) marks set maximum drafts; the summer load line is the governing limit in tropical summer zones.

Liquid cargo heel and free surface must be included in stability calculations for partially filled tanks.

Under MARPOL Annex I, oily water discharge overboard is generally limited to 15 ppm oil content, and only where permitted.

Reportable discharge: any discharge that violates applicable limits or causes a sheen on the water must be reported to the Coast Guard/National Response Center.

Spill response priorities: safety of personnel, stop the source, contain, then recover; never disperse without authorization.

Boom deployment: use containment boom downwind/downcurrent of the spill to capture and concentrate the slick.

Oil Record Book entries must be made for ballasting, transfer, and disposal operations; false entries are a criminal offense.

Prevention equipment: drip pans, scuppers plugged, absorbent materials, and a containment boom ready at the transfer site.

Notify the port authority and Coast Guard before transfer; maintain a spill response plan and posted emergency numbers.

Waste segregation: oily waste, hazardous waste, and garbage are handled separately per MARPOL Annexes I and V.

Fire triangle: fuel, oxygen, heat; hydrocarbon fires are Class B and extinguished by foam, CO2, or dry chemical (smothering).

Fixed CO2/foam systems require securing ventilation and confirming all personnel are clear before discharge.

Hot work permits require gas-free certification, fire watch, and isolation of adjacent tanks.

Confined space entry: test for oxygen (19.5-23.5%), flammables, and toxics before entry; never enter without a standby person.

Emergency procedures: sound general alarm, account for personnel, shut down transfer, and notify the master/Coast Guard.

Life-saving: immersion suits and life rings must be accessible; man-overboard requires immediate turn and marker deployment.

Gas detection: calibrated meters must be used; a reading above 10% LEL in the work area requires stopping operations.

Firefighting foam must be compatible with the product and applied as a blanket; water alone on burning hydrocarbons can spread the fire.

Barge types: tank barge (liquid cargo), deck barge (dry cargo), hopper barge (bulk), and spud/pile barges; each has distinct structural limits.

Hull structure: longitudinal and transverse framing, bulkheads divide tanks; watertight integrity depends on hatch and manhole seals.

Load line and tonnage marks are permanent; any alteration requires Coast Guard approval.

Inspection: annual and periodic inspections cover hull, tanks, piping, vents, and firefighting equipment.

Piping systems: cargo lines, vent lines, and sounding tubes must be labeled and color-coded; valves must be operable and marked.

Mooring equipment: winches, bitts, and lines rated for the barge's displacement; inspect for wear and corrosion.

Maintenance: keep bilges dry, inspect for corrosion and pitting, and record all repairs; structural cracks must be reported and repaired.

Vent and pressure/vacuum valves protect tanks from over/under pressure; they must be functional and unobstructed.

Rule 5: maintain a proper lookout by sight and hearing at all times; Rule 6: safe speed for conditions.

Rule 13: overtaking vessel keeps clear; Rule 14: head-on meeting, both turn to starboard.

Rule 15: crossing, the vessel with the other on her starboard side gives way; the stand-on vessel maintains course and speed.

Rule 19: in restricted visibility, reduce speed and use sound signals; radar alone does not relieve the duty to proceed at safe speed.

Towing lights: tow vessel shows two masthead lights in a vertical line plus sidelights and sternlight; tow length affects signals.

Navigation: use charted depths, tides, and currents; set a safe track with adequate under-keel clearance.

Mooring/seamanship: secure lines fore and aft, use spring lines to control surge, and monitor mooring during transfer.

Sound signals: one short = altering to starboard, two short = altering to port, three short = operating astern; five short = danger.