Clean Boating Tips: Petroleum Control

Petroleum in or on the water is harmful and, in some cases, fatal to aquatic life.  Floating petroleum is particularly bad because it reduces light penetration and the exchange of oxygen at the water's surface.  Floating oil also contaminates the microlayer.  The microlayer refers to the uppermost portion of the water column.  It is home to thousands of species of plants, animals, and microbes.  Ninety-nine percent of the Chesapeake Bay's blue crab larvae feed in the microlayer which also serves as a nursery ground for rockfish.  The abundance of life in the microlayer attracts predators: seabirds from above and fish from below.  Pollution in the microlayer, thus, has the potential to poison much of the aquatic food web.


The Federal Water Pollution Control Act (also called the Clean Water Act) prohibits the discharge of oil or oily waste into or upon the navigable waters of the United States or the waters of the contiguous zone if such discharge causes a film or sheen upon, or discoloration of, the surface of the water, or causes a sludge or emulsion beneath the surface of the water.  Violators are subject to a penalty of $5,000 from the US Coast Guard.  State law also prohibits the discharge of oil.  The Maryland Department of the Environment may impose additional fines.


Gas or diesel may be spilled during the act of fueling: as backsplash out the fuel intake or as overflow out the vent fitting.  Spills of this sort harm aquatic life, waste money, and can result in stains on the hull and damage to the gel coat and striping.  Follow these tips to avoid problems:

  • Fill tanks to no more than 90% capacity - gas that is drawn from cool storage tanks will expand as it warms up onboard your vessel.
  • To determine when the tank is 90% full, listen to the filler pipe, use a sounding stick, and be aware of your tank's volume.
  • Rather than filling your tank upon your return to port, wait and fill it up just before leaving on your next trip.  This practice will reduce spills due to thermal expansion because the fuel will be used before it has a chance to warm up. 
  • Fill portable tanks ashore where spills are less likely to occur and easier to clean up.
  • Use oil absorbent pads or containment jugs to catch all drips.
  • Slow down at the beginning and end of fueling