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Helmsmanship, 7 March 2010
Some of us can pat our head and rub our belly at the same time. Some of us can pat our head with our right hand and rub our belly with our left hand. The same people may not be able to change hands and do the same thing. Can you pat and rub with both hands? If you can't, you may need to work on your helmsmanship.
Several years ago we did some research on upwind steering. We found that we could identify the difference between good and bad steering technique. We used two GPS receivers to get our results. One was mounted on the stern and the other on the bow. A computer can measure and record the differences between the two receivers with some software. GPS system error is not a problem because both receivers have the same error. When we were sailing upwind, we steered up and down as the wind changed in speed and direction. No upwind course is a straight line. Most of us steer with our left hand on a starboard tack and our right hand on a port tack. We want to be on the high side in most cases when we are going upwind and steering a tiller sailboat. Of course the best upwind course is the shortest and fastest.
The continuous line in the picture below shows the stern GPS position. The short lines show a course change between the stern and the bow receivers. Notice that we gain speed after we head up during a course change. If we didn't gain speed, we misread the heading change. The first figure is the course and the second figure is the speed. The first picture shows a starboard tack and the second picture a port tack. The second picture shows more speed and fewer gusts. This was a port tack with more wind coming off a point of land where our creek started. We did the tests with land on both sides. Our test course was two 1/2-mile upwind legs. The first leg was a starboard tack with two right-handed sailors using their left hand on the tiller. The pictures show the course and speed for the test with the best results. The other helms person sailed a good test, but he didn't point up as much on his first starboard leg. Both port tacks looked about the same. Our results indicated that a right handed sailor should sail a good port tack and that some right handed sailors may have control problems on a starboard tack. We didn't do the test with a left handed sailor.
The way that all sailors sail upwind is to point higher on lifts. When the wind changes in our favor, we point our bow up towards the wind. The amount of helm change to increase your position towards the wind in a smooth and effective way is an important part of sailing upwind. The reason for pointing up is easy to understand. We want our sailboat to go to an upwind position as fast as possible. Most sailboats will go upwind without a person at the helm. Some sailors can make lifts very smooth and some can't. We have measured the pointing ability of some sailors with our recording equipment and in some cases; the boat will point higher with a locked helm.
The reason why a sailboat points up on its own is a little more difficult to understand. When the wind increases in speed (a gust), a balanced sailboat sailing on the wind will point up on it's own because the center of effort will move aft. With more power behind the center of lateral resistance (keel pivot point), the boat's bow moves towards the wind. At the same time, we have more water moving past the keel and with the increase in speed, the keel has more lift. The sails and the keel are working together to increase our progress toward the wind.
A lift can change from not being able to see the changes in a light wind to the boat pointing directly into the wind in a small gale. Good helmsmanship with a balanced boat requires lots of practice in all wind conditions.
The other part of going upwind and good helmsmanship is sailing into and out of a header. A header is a wind change in the wrong direction. A wind change is taking you away from your upwind sailing destination. It's decision time. Do I tack back towards my destination or will the wind change again and give me a lift. Some people will follow a header forever and end up going the wrong way. Some people tack on the first hint of a header and then have to tack back soon thereafter. You slow the boat on every tack.
You should be able to see the lifts and headers in the pictures above. Both pictures were sailed by the same sailor. The terrain caused the differences between the lifts, headers and speed in the two pictures. You can see from the picture below how the terrain would effect the tacks. The point of land at the end of the port tack caused a minor change of course.
How the terrain can change surface wind direction can be seen in one of our Sun Cat recordings. It's more difficult to see from the boat. A good sailor will anticipate a wind shift by reading the surrounding terrain. Can you see the 2 lifts and 1 header in our JAVA Script. The wind was blowing from the south/southwest and the top of the map is north.
We had 2 people steering the Sun Cat during our test sail. Some of low speeds during the early part of the test was from lack of wind. The last 3 tacks before rounding Mark 1 demonstrated some good helmsmanship. Using an imaginary Carpenters Square as a guide, the first 4 tacks were not that good. Using the same Carpenters Square on the last 3 tacks before Mark 1, we appeared to sail 90 degrees or 45 degrees on each side of the wind. We were sailing on a little lift before the 5th tack, but we ran out of wind (blocking trees on land) and had to tack. The track before the 7th tack ran us into a header and we had to tack. The wind was blowing into that little bay and curving around the edge. The terrain caused our lift and that big header. When the wind comes out of the south, it funnels perpendicular to the terrain on both sides of Mark 1. When you pass behind the land on the starboard side, you normally slow down. The beam reach between Mark I and Mark 2 helps with our overall speed. We maintained a course that prevented a jibe after rounding Mark 2. When we reached the stronger funneling winds on the downwind leg, we took advantage of that change as a downwind lift. All and all, a good sail in moderate winds.
I sometimes talk to customers about driving cars. Driving a dune buggy and driving a big town car isn't the same. Learning to drive a big smooth automobile with an automatic transmission is easy compared to driving on rough terrain in a dune buggy. The same thing happens with big heavy sailboats and little light sailboats. Many people purchase little sailboats and they want to learn how to sail, but they fail to learn. No one can learn how to sail on a little light boat. You already have to know how to sail to sail a boat like that. They sometimes trade their daysailors in on the heavy boats that I sell and I know from experience that this is true. You can see cause and effect on the heavy boat and you can't see it on the quick little daysailor.
We talked about cars and now we need to talk about helicopters. The CH-53 (click War Stories, HMM-165 on the lower left) that crashed in the Philippines had a steering problem. It was human error that caused the crash. Facts: A helicopter can't hover out of ground effect as well as it can in ground effect. The aircraft loaded lots of building supplies for a hospital that was going to be built on the side of a mountain. The aircraft took off from Clark AFB at sea level and flew to a village that was located at 5000 feet. Air density at sea level is greater than it is at 5000 feet. The aircraft had to hover out of ground effect to land at the village. Results: The aircraft crashed next to the landing field on its second landing attempt. The pilot experienced lack of rudder control over the landing area. Cause: The aircraft's gross weight was more than it should have been for landing at that altitude. The power required to maintain a hover at his altitude and weight was greater than the tail rotor could control. The pilot had the left rudder pedal on the floor and the aircraft still wanted to go right.
The tail rotor on a helicopter maintains the machines fore and aft attitude. As the torque or pitch of the main rotor system changes, the tail rotor changes to maintain the aircraft's fore and aft attitude. If you lose your tail rotor, you will spin in circles. What causes an increase in weather helm on our sailboat? We go from one hand on the tiller to two hands on the tiller. We can also put our foot in a position to pull on the tiller with more force. In lots of wind, the boat will round up when the rudder is overpowered. That sounds a little like the helicopter. We are not going to crash the sailboat, but the forces acting on the helicopter and the sailboat are both operator error. If we move the camber in the sails forward as the wind increases, we will be able to maintain one hand on the tiller and be in control and balanced. If the wind is great enough, reef the main sail or reduce sail size. The secret to good helmanship is boat balance.