Crossing a Harbor Bar ~ by John Kretschmer
One of the most difficult, and dangerous, maneuvers in a sailboat is getting through the break produced by a harbor bar.
I can remember an exhilarating
passage south from
Annapolis, MD one year. I was conducting an
offshore navigation training program aboard a cutter-rigged Stephens 47. My four inexperienced crewmates had done a terrific job of helming and standing watch through four days of challenging conditions. A
hurricane east of
Bermuda had spawned huge seas while we were bound for the
Bahamas. Although the winds we were experiencing were only in the 20 to 30-knot range, the seas, measured in feet, could be accurately described with the same numbers. We were tired and ahead of schedule, so instead of spending another night at sea I decided to detour to Marsh Harbor in the Abacos.
The winds had eased up, although the seas were still quite large as I altered course to approach the North Man of War Channel. I had been through this cut several years before, but just to be safe I turned to the 'Man of War Cay' section of the Yachtman's Guide to the
Bahamas for guidance: "This entrance from the ocean through the outer reef to the shelter of the cays is wide, deep, and straightforward, except during very strong onshore winds or during a rage, when the channels are impassable." The thought of a full night's sleep and a cold
beer at the Conch Inn temporarily clouded my common sense.
Under
power, I approached on the recommended heading of 212 degrees magnetic and searched for the opening in the reef. It was virtually impossible to spot because waves were breaking all across the harbor bar. I knew that what I was doing was not recommended in Seamanship 101, and was possibly dangerous, especially as the
boat lifted to a large swell. Two miles from the pass, I suggested to the crew that we might not be able to negotiate the channel. The disappointment was easy to read in their eyes. "Well, we'll proceed a bit further and check things out." I tried to raise somebody, anybody, on Man of War Cay for some
advice and to find out the state of the tide, but I suspected that our
radio wasn't transmitting. Less than a mile from the pass, what had been large swells farther
offshore, were now steep, curling waves. It finally dawned on me that these were
classic 'rage' conditions and I knew then that there was no way we could safely navigate the pass. But it was almost too late.
Just as I started to turn the
wheel, one of the crew members looked aft and screamed, "Hold on." A wave, much larger and steeper than others, lifted the stern and then broke with a thundering crash. Sixteen tons of
boat skidded forward like a toy in a bathtub. Green
water washed over the
deck. For a horrible second I thought we might pitch-pole, then, I thought surely we would roll over. I steered with all my strength, concentrating on keeping the bow perpendicular to the flow of the wave. At last it overran us. I did an immediate
head count, everyone was still aboard, then I looked aft. The huge wave had momentarily disrupted the pattern, there was a break, almost a slick on the
water. I yelled, "Hold on!" and quickly spun the boat about. Accelerating, I steamed back toward deep water and started to breath again once we were beyond the breaker line.
When you watch the waves at a harbor bar toss about a 40-foot
aluminum Coast Guard vessel, you know these places don't suffer fools lightly.
Bars by their very nature are hazardous, and this has nothing to do with alcohol. Crossing a bar, be it in a river mouth, passing through a break in a reef, or between stone jetties protecting a narrow inlet, is one of the most difficult and potentially dangerous maneuvers sailors can attempt. Sandbars are natural deposits that form where deep and shallow water meet, which of course is the very spot where we find our way into many harbors. Shoal waters dramatically alter wave action. When an incoming wave moves into dangerously shallow water, the wave length first decreases and then increases as the wave breaks. Anyone who has surfed, or even bodysurfed, at the beach can recognize the phenomena. As waves move through the surf zone, the height increases until the waves become completely unstable and dangerous to vessels of all kinds.
Running a harbor bar requires good information, patience, and common sense. I recently delivered a 36-foot
sloop from Ft. Lauderdale to Brielle, NJ. We arrived off the Manasquan Inlet with a stiff east
wind causing a fearful chop with visible breaking waves. According to the NOAA
weather broadcast, the tide was at max ebb. Instead of trying to force our way in over the bar, we hove-to on the offshore tack and had a peaceful lunch. Several hours later, with the tide about halfway into the flood, I climbed up to the spreaders and from well beyond the breaker line, surveyed the inlet again. Although the conditions were much improved, I decided to wait until just before the flood slack to make our entrance. I was unusually cautious because the boat drew almost seven feet and delivering her to her owner, in one piece, was more important than spending a couple extra hours at sea. When we finally made our approach, the
wind was still blowing, but the inlet was quite manageable.
Picking your way through a reef
passage can be most unnerving. On an expedition that retraced the maritime routes of the Ancient Maya, I became fairly adept at picking my way through thundering reef passages, but never quite came to enjoy it. The most critical element of running a reef is to be certain you know exactly where the pass is before you commit your boat. This is not always an easy task, especially if there is a strong onshore breeze causing waves to break all along the reef. If you are confident of your
charts and
guidebooks, try to make sense of landmarks ashore. Sail parallel to the reef at a safe distance and look for an obvious change in color where you suspect the pass to be.
Even under the most benign conditions, getting caught in a harbor bar (like this one off Guatemala's Rio Dulce) can bring grave consequences for the boat owner.
I remember once anxiously trying to find the Ranguana Cay Pass in Southern
Belize. We had sailed overnight from the Bay Islands of
Honduras and onshore winds and seas were building rapidly. I knew that if we didn't find the pass in short order, we might have to sail over one hundred miles north to the main ship channel, which was an unhappy prospect at best. I paralleled the reef while Lesa looked from the ratlines. Once, twice, three times we passed along the break line. Finally we were confident we had the opening scoped out. The
charts and
guidebooks for the pass were vague. Reef running requires that you use your natural senses and— yes, I am repeating myself—patience. Although there was a lot of wind, I started the
diesel and rolled in the yankee. With the main and staysail sheeted flat, we shot through the pass into the surprisingly quiet waters behind the reef. It is important to maintain speed when crossing bars in order to keep
steering. More problems are caused by going too slow than too fast. Sometimes, in really wild bar conditions, your only hope is to maintain speed. But these are situations you should avoid at all costs.
Sometimes you can use the wave action caused by bars to help you make an approach. The Rio Dulce is a lovely oasis in
Guatemala. A deep, freshwater river, the Rio Dulce slices through a rain forest for more than 20 miles. There are several safe,
cheap marinas at the
head of the river. Unfortunately, the bar at the mouth carries about six feet at high water. My 44-foot
ketch draws seven feet. Usually I am forced to hire a small tug that takes my main
halyard aboard, heels the boat over precipitously, and ignominiously escorts me across the bar. Once however, a strong onshore wind and the short chop caused by the initial ebb of the
current, was enough to let me bounce over the bar and into the River. You have to use what you can.
Bar Crossing Guidelines (Sidebar)
Before you attempt to cross any bar in rough conditions, know the state of the tide. Even the small one-foot tidal range at Rio Dulce makes a significant difference in the conditions. The best time to cross any bar is just before slack water at high tide. Remember that during spring tides, when the moon and sun are working together and tides are extreme, conditions will be rougher.
Be patient and obtain good information. Don't just charge across the bar, but take the time to
survey the situation from a safe vantage point beyond the break line. If you suspect conditions will improve based on tide or
weather, don't hesitate to wait. There is no prize for being first over the bar. Contact people ashore on the
radio about the conditions. This is one situation where the Coast Guard is usually interested in providing
advice. Be wary, however, of advice from amateurs and also be wary of blindly following other boats, especially if they are significantly different than yours. A 30-foot sport fisherman that can run at 20 knots can literally outrun waves into the harbor. You are not likely to do the same in your old
Pearson 30.
Be observant. It is a pity that ratlines are completely out of fashion on modern boats, because gaining height of eye can really be helpful.
Mast steps perform the same function, but they are not as user-friendly. As a last resort, climb up on the goosneck. Remember, waves always look smaller from behind. In other words, as you proceed forward you are looking at the back of the waves. As you approach a harbor bar, look behind you too, to help get a perspective on the wave height and breaking characteristics.
Know your boat. In general terms, longer, lighter boats can maintain speed, surf more easily and do better in rough bar crossings. Heavy boats respond more slowly and if they don't rise quickly to the steep waves, can be pooped, which is really dangerous. Of course lighter boats can become difficult to steer if the
rudder is lifted out of the water.
Once you begin a bar crossing and pass beyond the breaker line, you are committed. At this point concentrate all your energy on
steering and watching the wave patterns. You will have plenty of time to talk about the event after the boat is safely tied up or swinging to the
anchor. Then you can saunter over to the other bar, where things are usually a little less hectic.
John Kretschmer
From the ‘Sailnet’ Archives: http://www.sailnet.com/collections/seamanship/index.cfm
***
See also:
Crossing the Bar ~ by Andy Galwey
This very important subject is often misrepresented and misunderstood. Australian Andy Galwey provides an in-depth look at how to tackle white water bar crossings (small craft).
http://www.marinews.com.au/boating/b...s/ba_barc.html
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