Kayaking in Commercial Traffic
Being Seen! - PART II
Speed of Commercial Craft
by Ralph Díaz
Few paddlers really appreciate how fast a commercial ship can move, even those that seem bulky and cow-like in their appearance. Speeds amaze even very experienced paddlers. Here is what John Chamberlain of San Francisco, California relates on the movement of large ships in his paddling waters of San Francisco Bay.
A friend and I were going from Alcatraz back to San Francisco. We saw a large tanker was just moving under the Golden Gate Bridge. Beating it across seemed to be little problem. But as we set off we realized that we had greatly underestimated the speed of the tanker and wisely decide to do a U-turn out of its way. Luckily we did back off because it became clear that we would never have made it! Lesson: Tankers move very fast, although their size makes their speed deceiving.
Many such vessels can hit 20 knots. Distances are very hard to judge unless you have an idea of a commercial craft’s size. And even then you can never absolutely be sure. An incoming tide in some places can give a ship 3 or 4 knots of added speed. It may be lightly loaded and not drawing as much water. All factors that add to the craft’s effective speed.
Backing off is generally a smart idea unless you are very familiar with the particularly situation. For example, take the Hudson River off of Manhattan. It is almost a mile wide. When crossing the channel you can generally beat a barge and tug combination across if you are aware of conditions that you know will impede its progress. If it is bucking the currents and wind, you can be pretty certain it will be slowed down. You can be doubly sure if that barge is low in the water. Most the barge will be underwater and cause considerable drag
.However, if it is moving with the wind and current and the barge is riding high, watch out! It will eat you up. You would be certain to be hit because the tug/barge combination has little hope of slowing down to avoid you or, indeed, little ability to maneuver around you even if it wanted to and could move toward water in which it would not be risking running aground.
Limits On Their Maneuverability
This is important to bear in mind. Large ships require room to stop. They also need space to get around any obstacles in the water, even assuming that they can spot something as small as a kayak or two.
A few years back there was an interesting article in Sea Kayaker (Summer 1992 pp. 21-25, written by Rick Spilman) that dealt with ships, tugs, etc. Most of it was quite familiar except for one item that opened my eyes wide. It was a reproduction of an example of the maneuvering diagram that every large ship must post on its bridge to let the helmsman know how much room he needs to stop the ship and how much to turn in each direction. The diagram covered situations when fully loaded and when empty except for ballast. And indicates stopping and turning distances (and drift arcs) for moving at full and half speeds.
The ship in the example was a 550 foot long cargo ship. To come to a full stop if operating at full speed and fully loaded it would take over 4 minutes on this particular ship and a distance of some 1,128 yards or about 2/3’s of a mile. Even when empty and moving at full speed it would take over 3 minutes and almost 1,000 yards! These would be emergency stops with engines running fully astern. Another critical point was revealed in the diagram regarding stops: the ship would be turned slightly to starboard. This is the result of the direction of the turning propellers.
The effect of the rotation of the propellers can also be critical in maneuvering. The ship, and any ship for that matter, will turn better in one direction than another because of the effect of the propeller’s rotation. The diagram shows what happens when the ship makes an emergency 90 degree turn in either direction with the engine running fully astern. At full speed and empty, the ship could be turned almost twice as sharply if turned toward starboard as opposed to if turned toward its port side. Downrange some 600 yards, the ship would have been able to turn about 500 yards off its original course if going to its starboard compared to only about 350 yards from straight ahead when going to port.
This makes something pretty clear. If the ship’s crew sees you dead ahead and the ship is turned toward its right it would have a better chance of missing you than if it were turned to its left. I don’t know what lesson can be drawn from this fact except pray that the ship goes to its right.
Being Seen And Seeing !!!
As indicated in the article in the last issue of the newsletter, you should work on being more visible and at the same time assume you are not being seen. While keeping the latter point in mind, here are some observations on being seen:
Regarding the color of paddles, one reader e-mailed me saying that he thought that white paddle blades are the way to go for improving your chances of being seen. The reader, Tom Anthony of upper New York State, also emphasized that keeping you paddle moving and the blades flashing as they move through various planes of light, enhances the chance that your paddle will draw the attention of a motorboat operator.
White, indeed, is a pretty good color. I once recall being able to spot a paddler who had been separated from our group. We could see the reflection of the sun off of his paddle even though he was almost a mile away and lost against the background of a populated coastline. His paddles were moving at a rapid pace and that windmilling, as Tom rightly reports, caught the attention of our group. White, however, is limited under some circumstances. If the water is rippling with small whitecaps, your white paddle blade may not go noticed against the irregular changing pattern of wave tips. Yellow is much better. It will never get confused with anything. It reflects light as well as white and draws attention whether being moved rapidly in a paddle stroke or held up high.
Whatever you do, avoid the temptation to use black paddles or fashionable colors such as dark purple, etc. Also note regarding graphite paddles: the price of having a graphite paddle is not only the extra cost but also the need of manufacturers to make the backside of the paddle blades black because of the peculiarities of graphite. So for some directions around you, all that will show is black, which is fairly invisible on open water.
Several readers indicated that a good thing to have when paddling is one of those small mirrors used in bicycling that attaches to your regular glasses or sunglasses. These are meant to help bicyclists see what is coming up from their rear. Such a clip-on mirror would certainly help alert you to a boat coming up from behind you. If you are going to use one make certain to practice with it in non-emergency situations to get a sense of its depth of field, perceptions of distance and other such considerations when looking into any rearview mirror. Also, determine how well it will work for your particular paddling style. Some people don’t keep their eyes very level when paddling and this may jar the rearward view. Also, the up and down movement of your kayak in chop will affect what you can see behind you through the narrow field of a mirror.