A Test Run
By Tim Long #465 "Tim's Sail Boat" (1ar)PDR-465's test run, by Tim Long
A few years back I registered 465 and told a story about a boat I built around 1956. The design was exactly like a PDR except the curve on the bottom could be slightly different. There is no way to measure it now. In 2020 I wrote up the story of PDR-465 (the registration number you provided based on my story) The recent article on motoring a PDR reminded me of the chapter titled 'A Test Run'
A test run
In the previous summer, Max and I had spent a week camping at square lake in the Adirondacks. On seeing PDR-465 Max decided that we should take it camping this summer in our second annual camping trip. (Actually, there were only two.) We were only two weeks away from leaving on this summer’s trip to the Adirondacks and PDR-465 had not been tested. The first weekend was not available for testing because Max had a job driving two old neighborhood ladies to appointments. This weekend was their monthly meeting at the spiritualist camp in the southern tier of New York State.
The next weekend was one week before the camping trip and the last chance to test PDR-465. The obvious test site was Owasco Lake which is one of the Finger Lakes. It was a bit large for PDR-465, being a mile wide and much longer. Also, there was a slight problem in getting out into open water. The public boat ramp and approach to the lake was on the outlet, a narrow river of water more like a canal because of a water level control dam further down-stream. The narrow width and trees made it not at all conducive to sailing. Also, there was a small bridge halfway between the boat ramp and the lake. The bridge is no problem for motorboats, but not passable for sailboats with an erect mast. The solution was to lower the mast and use an outboard motor. A small outboard would have done fine, but the only one available was a 7.5 hp Evinrude long-shaft outboard.
At this point in the story a diversion into basic physics would be appropriate to enhance understanding of what was to happen next. It has to do with the effect of levers and torque first studied by Archimedes. Just as a linear force can be viewed as a push or pull, a torque can be viewed as a twist or rotation of an object about an axis. The strength of a torque is proportional to a force applied perpendicularly to a lever arm multiplied by the distance from the lever’s fulcrum. Now consider that the shaft of the Evinrude is the lever and the fulcrum is the motor mount on the back of PDR-465. The length of the shaft is around three feet and the motor mount less than one foot. The force of the propeller has at least three times its force tending to rotate the bow of the sailboat upward and back. That advantage gives a considerable torque to PDR-465 about its center of rotation. The effect of the torque is to lift the bow. In addition, with the bow rotated up and the stern down, the sailboat pushes a significant wave in front of the boat. In a normal outboard mounted on the stern, the propeller is close to the bottom of the boat and the torque lifting the bow up is minimal so the boat can be forced to skim across the surface. Not the case with the puddle duck.
In the outlet on the way to the lake at a slow speed there was no problem in idling the motor and keeping PDR-465 stable in the water. The weight of the boat held the bow down and the boat and I traveled nicely out into the lake at a rather boring slow speed. Once out in the lake, the mast was mounted in its proper position and the sail hoisted up the TV antennae and the beam moved to luff position. Looking around at other boats, it appeared that the good wind was further out toward the middle of the lake. The slight wind near the outlet was not moving the PDR very fast and it was decided to use the Evinrude to reach the good wind. However, at idle speed it would take some time to get into the better wind. The obvious solution was to crank up the speed on the outboard, which meant increasing the torque raising the bow. Usually in a motorboat when one wants to go fast, one increases the speed until the boat is just skimming along the top of the water. On cranking up the speed, the bow noticeably rose up and PDR-465 did not flatten out as hoped on the water. Next, I figured that more weight up front was needed so I leaned forward and cranked up the speed a bit more. From experiences in other motorboats I knew that to flatten out the boat and reach maximum speed, the motor needs to be on maximum power and sometimes one has to push the bow back down. It was about that time that I noticed that the boat was not reacting according to theory, the bow was still moving up and we were pushing a growing large wave in front of PDR-465. It seemed that the PDR was approaching a vertical angle. Clearly, the torque of the Evinrude and the growing pile of water in front was more than the weight of the boat could overcome. In retrospect, the mast and sail were also contributing to the effects of the torque of the outboard. Then I looked toward the stern of PDR-465. What I saw created an adrenaline pulse that induced an immediate thought process of what to do next. Another wave was there which was frighteningly higher than the back of the boat and the motor. If I were to cut the motor back, nothing would stop that wave from riding over the transom and sinking the boat. It is amazing how adrenalin-enhanced fear can speed up the thought process. Using some quick logic, I concluded that a gradual slowing of the motor would be the safest approach to the looming disaster. Once stable, I accepted a slow idle-speed trip to the better wind.
Looking back, after more sailing experience, the test sail of 1957 was not great, discounting the attempted rapid transit to the lake center. The sail was not tight enough nor was it properly designed. However, it did work, and I completed a couple half-mile transits back and forth near the center of Owasco Lake. Putting the Evinrude back into action on idle I returned to the boat ramp. The idle speed provided plenty of time to analyze the success of the test sail. In conclusion, I considered the test a moderate success, but PDR-465 was not a sailboat appropriate for a large motor or large lake. Perhaps a stronger wind would have helped.
Enjoy!!
A few years back I registered 465 and told a story about a boat I built around 1956. The design was exactly like a PDR except the curve on the bottom could be slightly different. There is no way to measure it now. In 2020 I wrote up the story of PDR-465 (the registration number you provided based on my story) The recent article on motoring a PDR reminded me of the chapter titled 'A Test Run'
A test run
In the previous summer, Max and I had spent a week camping at square lake in the Adirondacks. On seeing PDR-465 Max decided that we should take it camping this summer in our second annual camping trip. (Actually, there were only two.) We were only two weeks away from leaving on this summer’s trip to the Adirondacks and PDR-465 had not been tested. The first weekend was not available for testing because Max had a job driving two old neighborhood ladies to appointments. This weekend was their monthly meeting at the spiritualist camp in the southern tier of New York State.
The next weekend was one week before the camping trip and the last chance to test PDR-465. The obvious test site was Owasco Lake which is one of the Finger Lakes. It was a bit large for PDR-465, being a mile wide and much longer. Also, there was a slight problem in getting out into open water. The public boat ramp and approach to the lake was on the outlet, a narrow river of water more like a canal because of a water level control dam further down-stream. The narrow width and trees made it not at all conducive to sailing. Also, there was a small bridge halfway between the boat ramp and the lake. The bridge is no problem for motorboats, but not passable for sailboats with an erect mast. The solution was to lower the mast and use an outboard motor. A small outboard would have done fine, but the only one available was a 7.5 hp Evinrude long-shaft outboard.
At this point in the story a diversion into basic physics would be appropriate to enhance understanding of what was to happen next. It has to do with the effect of levers and torque first studied by Archimedes. Just as a linear force can be viewed as a push or pull, a torque can be viewed as a twist or rotation of an object about an axis. The strength of a torque is proportional to a force applied perpendicularly to a lever arm multiplied by the distance from the lever’s fulcrum. Now consider that the shaft of the Evinrude is the lever and the fulcrum is the motor mount on the back of PDR-465. The length of the shaft is around three feet and the motor mount less than one foot. The force of the propeller has at least three times its force tending to rotate the bow of the sailboat upward and back. That advantage gives a considerable torque to PDR-465 about its center of rotation. The effect of the torque is to lift the bow. In addition, with the bow rotated up and the stern down, the sailboat pushes a significant wave in front of the boat. In a normal outboard mounted on the stern, the propeller is close to the bottom of the boat and the torque lifting the bow up is minimal so the boat can be forced to skim across the surface. Not the case with the puddle duck.
In the outlet on the way to the lake at a slow speed there was no problem in idling the motor and keeping PDR-465 stable in the water. The weight of the boat held the bow down and the boat and I traveled nicely out into the lake at a rather boring slow speed. Once out in the lake, the mast was mounted in its proper position and the sail hoisted up the TV antennae and the beam moved to luff position. Looking around at other boats, it appeared that the good wind was further out toward the middle of the lake. The slight wind near the outlet was not moving the PDR very fast and it was decided to use the Evinrude to reach the good wind. However, at idle speed it would take some time to get into the better wind. The obvious solution was to crank up the speed on the outboard, which meant increasing the torque raising the bow. Usually in a motorboat when one wants to go fast, one increases the speed until the boat is just skimming along the top of the water. On cranking up the speed, the bow noticeably rose up and PDR-465 did not flatten out as hoped on the water. Next, I figured that more weight up front was needed so I leaned forward and cranked up the speed a bit more. From experiences in other motorboats I knew that to flatten out the boat and reach maximum speed, the motor needs to be on maximum power and sometimes one has to push the bow back down. It was about that time that I noticed that the boat was not reacting according to theory, the bow was still moving up and we were pushing a growing large wave in front of PDR-465. It seemed that the PDR was approaching a vertical angle. Clearly, the torque of the Evinrude and the growing pile of water in front was more than the weight of the boat could overcome. In retrospect, the mast and sail were also contributing to the effects of the torque of the outboard. Then I looked toward the stern of PDR-465. What I saw created an adrenaline pulse that induced an immediate thought process of what to do next. Another wave was there which was frighteningly higher than the back of the boat and the motor. If I were to cut the motor back, nothing would stop that wave from riding over the transom and sinking the boat. It is amazing how adrenalin-enhanced fear can speed up the thought process. Using some quick logic, I concluded that a gradual slowing of the motor would be the safest approach to the looming disaster. Once stable, I accepted a slow idle-speed trip to the better wind.
Looking back, after more sailing experience, the test sail of 1957 was not great, discounting the attempted rapid transit to the lake center. The sail was not tight enough nor was it properly designed. However, it did work, and I completed a couple half-mile transits back and forth near the center of Owasco Lake. Putting the Evinrude back into action on idle I returned to the boat ramp. The idle speed provided plenty of time to analyze the success of the test sail. In conclusion, I considered the test a moderate success, but PDR-465 was not a sailboat appropriate for a large motor or large lake. Perhaps a stronger wind would have helped.
Enjoy!!
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