|When driving in a car, we follow a well defined path of pavement which we can see underneath the car and stretched out before us. We know at all times how we are doing and if we are proceeding in the correct direction to follow the course defined by the pavement. This is not the case when out on the water. While we can see how we are progressing through the water, the water itself may be moving relative to the land. Where we are pointing the bow may not be where we actually going. ( For an article about bearing, heading and course, click here.)
A compass is of no help in determining what progress we are making to a particular point. It tells you the direction to the North Magnetic pole, thousands of miles away. That compass reading changes very little if you move 2 miles to the right or left. The bearing to your objective is what is changing significantly. But taking a bearing can be difficult even with a deck compass.
If you have a working GPS, it will show you the distance and direction to your objective and how fast you are getting there. But what if a GPS is not available? What if it is not working? What if it is in your day hatch compartment? What if conditions do not allow you to look at it, it is too rough or you can not see it due to rain or sun? What if you are not sure what the point you are trying to get to is on the GPS map?
There is a simple and very effective technique to gauge how you are doing in getting to a particular point. That is a range.
We know that two points are required to define a line. So if we can observe two fixed (stationary) points close to where you want to go, whether they be on land or on the water, they will define a straight line for us between the two fixed points that extends out as far as we can see the two points. These two fixed points are called a range pair, or simply, a range. The fixed points can be anything that does not move. A TV tower, a cell tower, a water tank, a gap in a tree line, a tall tree, a white house, a pile in a bridge, a buoy or a fish trap stake - any of these unmoving objects can make a range point. It is helpful if the one farther away is visually taller than the one in front. That way the near one never disappears from view. ( You can still use a range where the far range point is covered by the near range point when they are aligned.)
As long as the two range points stay aligned vertically with each other, you are proceeding along the straight line between these two points, which is the course you wish to follow. No matter what direction you have to set for your vessel to keep these two points aligned, you are in fact moving in a straight line to the near range point. However, if current or wind has pushed you to the right of the range line, the far range will move to the right of the near range. You will need to head more to the left to get back on course where the two range points are aligned. If you are to the left of the straight line, the far range will be to the left of the near range.
You can practice running a range in your own lawn. Pick a tree and a post on a fence line to create a range when making your first pass with a mower. Step to the right and observe the range points. Step to the left and observe. Keep the two aligned as you walk across the yard. Your cut will be straight.
The closer you are to the near range the more sensitive the range is to deviations from the straight line path.
So with this simple technique of keeping the vertical alignment of two fixed points you can stay on course, completely compensating for wind, waves and current. It costs nothing, is easy to use, simple, good for difficult conditions and completely effective. The only mistake that gets you off course is choosing a range point that is not fixed to the earth, such as a boat at anchor, a tanker that is under way, a cloud, the sun, the moon or stars. These are all in motion and hence so is the straight line defined by their location.
If you can't find two points in front of you, you can use two fixed points in back of you. This is called a back range. It works just like the front range. A back range is easy to use in a larger vessel but more difficult in a kayak. Turning a kayak from side to side to observe a back range can give you a check on how you are doing and whether you are off course and how you need to alter your heading to stay on course.
There is another ranging technique that is very useful. When encountering another moving vessel on the water, how do you tell if you are on a collision course with it? Can you tell if you are going to pass in front of it or behind it? If you sight the vessel against the background of a far shore or a buoy or any other fixed point, if the shore behind the vessel is appearing as you approach, then you are going to pass in front of the other vessel. If shore in front of the vessel is disappearing behind the vessel then you are going to pass behind the other vessel. If the vessel seems to not be moving against the shoreline, then you are on a collision course. The faster the land appears or disappears behind the other vessel, the farther away it will be when your two courses cross. ( When using this technique for a tanker be sure to sight on both the bow AND stern of the tanker. You may not be on a collision course with the bow but you might be with the stern. )
So use a range and get home safely and efficiently.