If you're boating in waters where there are large oceangoing vessels, here's a piece of sound advice: As soon as you see a big ship, do whatever you can–immediately–to get out of the way.

Never mind the great photos you can get up close, or the thrill of being right alongside one of these behemoths. Big ships are a serious threat to recreational boaters, and there's usually nothing these vessels can do to change course or speed in time to avoid an accident. So it's up to you to stay clear.

When recreation boats meet commercial ships, the former usually have more control. Large ships have difficulty stopping, lose steerage at slow speeds and often cannot maneuver for fear of running aground."When I have a recreational boat coming at me, it's basically his call on whether we collide," says Capt. John J. Colgan, a Chesapeake Bay pilot who guides oceangoing vessels transiting the 115-mile route from the Atlantic Ocean to Baltimore Harbor. "There's not a lot we can do if he isn't looking or doesn't want to get out of the way."

First, the legalities: Whatever your previous impressions, the rules of the road do not give you the right of way over oceangoing vessels, even if you're on a sailboat. Unless you are out in ocean waters, big ships are likely to be confined to a narrow shipping channel, and they cannot leave it without running aground. Coast Guard navigation rules require that you take steps to avoid them.

There's also the matter of visibility. Even on clear days, there's no guarantee that the crew of a large vessel will be able to see you, let alone steer around you. Oceangoing vessels usually are so tall and their bridges are placed so far aft that the helmsman has a blind-spot for at least a quarter of a mile ahead. Many radar sets won't even pick up fiberglass boats, except as tiny, indistinct blips. And the crew may not be monitoring the radar screen that closely. At night, your running lights may be difficult to see.

HOW LARGE SHIPS OPERATE

Big ships also travel a lot more quickly than most boaters expect. While merchant vessels may seem slow and lumbering, they usually travel at between 13 and 18 knots even in coastal or inland shipping channels. That means the ship that seems miles away could be right off your bow in minutes. Slow-moving sailboats and trawlers may find it difficult to escape if they wait too long. Even if you're on a fast boat, if your engine fails while you're in the middle of a shipping channel, you're in potentially serious trouble. New Coast Guard figures show there were 86 accidents in the U.S. last year that were due to engine failure–nine of them fatal.

As Colgan said, even if the captain or pilot does see you, there's usually little he or she can do to avoid a collision. Many large ships must travel at least 12 knots just to maintain steerage. Vessels that slow and lose control risk being driven aground in high winds or strong currents. Even if the captain reverses the engines, it takes 2,000 to 4,000 feet (or 4 to 6 minutes) for a ship to come to a full stop, and there's often no place for a deep-draft vessel to go. Big ships also have very little control when they back.

There's also the idea that getting too close to a big ship can itself be dangerous. Bow waves, propeller wash or wakes can rock your boat severely, draw you into the ship or–worse yet–into the propellers.

HOW YOU SHOULD OPERATE

One major safety measure is to make sure your boat is visible. Carry a radar reflector if you can–as high on your boat as you can place it–to enlarge the blip that the big ship sees on its radar. It won't guarantee that you'll be spotted, but it certainly will improve the chances. If you're going to be on the water at night, be sure your running lights work and aren't hidden by sails or equipment such as dinghies.A pilot looks out over the bow of his ship, where visability is often limited for a quarter mile because of the vessel's design.

Also, do what you can to be aware of approaching ships. Navigation aids such as radar equipped with ARPA (Automatic Radar Plotting Aid) or plotters equipped with AIS (automatic Identification System) can give you valuable information on approaching vessels, such as identity, course, speed and point of approach. At a minimum, you should maintain a constant lookout, especially at night, and make sure you look up and down the channel carefully to see whether big ships are coming. Even if it looks as though they're far away, they can be upon you in a matter of minutes.

Stay out of the shipping lanes unless you really need to cross them. If you have to follow the shipping channel, stay to the side and be aware of how much room you have outside the channel without running aground yourself. Also be aware of the tides. In some areas, large ships time arrivals and departures to tidal action, in order to facilitate the draft of their vessels.

It is up to recreational boaters to steer clear of large ships, not the other way around.When you do see a large ship coming your way, calculate how long it will take the vessel to reach your vicinity, and take action immediately to get out of its way–before you're in danger. If you can, head directly for the side of the shipping channel that's closest to you, even if it adds a few minutes to your trip. It may also help to learn the kinds of lights and whistle signals that an oceangoing vessel will have.

Be especially careful when you see a tugboat, particularly if it's towing a barge. Never try to cut between them. You will run into the towline and risk serious injury to you or your boat. The Coast Guard says collisions between recreational boats and barges are a major problem.

If you need to talk to the captain or pilot by radio, call on Channel 13, the frequency reserved for "bridge-to-bridge" communications, or conversations between you and the big ship's crew. There's less radio traffic there than on Channel 16, and large vessels are likely to be monitoring it more closely.