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#1
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On Wed, 18 Mar 2015 16:14:51 -0700 (PDT), Tim
wrote: Yes, at a very slow speed, the boat would back to the left only regardless of how you set the rudder, and that provided to be a royal pain in a few cases. === That issue is known as "prop walk" and it is most apparent at very slow speed before the boat gains momentum. Prop walk is caused by the propellor acting as a paddle wheel. Since the prop/paddle wheel rotation is perpendicular to the center line, a side thrust is created instead of forward motion. The direction of "walk" depends on the direction of shaft rotation. Since your boat is walking to the left we can assume the shaft is rotating counter clockwise in reverse (when viewed from behind the boat). Remember to think of the prop as a paddle wheel at low speed. There are other more complicated explanations for why prop walk occurs but the paddle wheel analogy is the most intuitive to understand and the easiest to apply to problem solving. As Richard pointed out, the rudder has very little effect in reverse until the boat gains some speed and creates water flow past the rudder. This is not a problem in forward because the prop creates plenty of water flow even when the boat is standing still. Backing up a single engine boat is an art form not a science. Every boat is a little different but some basic priciples apply. The best strategy I've found is to apply a quick burst of power in reverse and then shift immediately into neutral. Once you are in neutral there is no more prop walk, and if you have built a little speed, you can steer with the rudder. Sometimes you have to do this more than once. Another strategy is letting the prop walk work in your favor and just let the stern "walk" in the direction it wants to go. This implies some maneuvering room of course. |
#2
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posted to rec.boats
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On 3/18/2015 8:59 PM, Wayne.B wrote:
On Wed, 18 Mar 2015 16:14:51 -0700 (PDT), Tim wrote: Yes, at a very slow speed, the boat would back to the left only regardless of how you set the rudder, and that provided to be a royal pain in a few cases. === That issue is known as "prop walk" and it is most apparent at very slow speed before the boat gains momentum. Prop walk is caused by the propellor acting as a paddle wheel. Since the prop/paddle wheel rotation is perpendicular to the center line, a side thrust is created instead of forward motion. The direction of "walk" depends on the direction of shaft rotation. Since your boat is walking to the left we can assume the shaft is rotating counter clockwise in reverse (when viewed from behind the boat). Remember to think of the prop as a paddle wheel at low speed. There are other more complicated explanations for why prop walk occurs but the paddle wheel analogy is the most intuitive to understand and the easiest to apply to problem solving. As Richard pointed out, the rudder has very little effect in reverse until the boat gains some speed and creates water flow past the rudder. This is not a problem in forward because the prop creates plenty of water flow even when the boat is standing still. Backing up a single engine boat is an art form not a science. Every boat is a little different but some basic priciples apply. The best strategy I've found is to apply a quick burst of power in reverse and then shift immediately into neutral. Once you are in neutral there is no more prop walk, and if you have built a little speed, you can steer with the rudder. Sometimes you have to do this more than once. Another strategy is letting the prop walk work in your favor and just let the stern "walk" in the direction it wants to go. This implies some maneuvering room of course. Good explanation Wayne. I think many in this newsgroup are probably familiar with this but it bears repeating sometimes. In cases of close quarter maneuvering, "neutral" is always your friend. Like many I have witnessed, it took a while for me to understand this. The natural tendency of many is to "drive" the boat into the slip, often with catastrophic results. Learning to relax, shift often to neutral and let the boat take a "set" given the wind and current is much more effective. |
#3
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posted to rec.boats
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On Wednesday, March 18, 2015 at 6:14:36 PM UTC-7, Mr. Luddite wrote:
On 3/18/2015 8:59 PM, Wayne.B wrote: On Wed, 18 Mar 2015 16:14:51 -0700 (PDT), Tim wrote: Yes, at a very slow speed, the boat would back to the left only regardless of how you set the rudder, and that provided to be a royal pain in a few cases. === That issue is known as "prop walk" and it is most apparent at very slow speed before the boat gains momentum. Prop walk is caused by the propellor acting as a paddle wheel. Since the prop/paddle wheel rotation is perpendicular to the center line, a side thrust is created instead of forward motion. The direction of "walk" depends on the direction of shaft rotation. Since your boat is walking to the left we can assume the shaft is rotating counter clockwise in reverse (when viewed from behind the boat). Remember to think of the prop as a paddle wheel at low speed. There are other more complicated explanations for why prop walk occurs but the paddle wheel analogy is the most intuitive to understand and the easiest to apply to problem solving. As Richard pointed out, the rudder has very little effect in reverse until the boat gains some speed and creates water flow past the rudder. This is not a problem in forward because the prop creates plenty of water flow even when the boat is standing still. Backing up a single engine boat is an art form not a science. Every boat is a little different but some basic priciples apply. The best strategy I've found is to apply a quick burst of power in reverse and then shift immediately into neutral. Once you are in neutral there is no more prop walk, and if you have built a little speed, you can steer with the rudder. Sometimes you have to do this more than once. Another strategy is letting the prop walk work in your favor and just let the stern "walk" in the direction it wants to go. This implies some maneuvering room of course. Good explanation Wayne. Yes to both of you. Very good! I think many in this newsgroup are probably familiar with this but it bears repeating sometimes. In cases of close quarter maneuvering, "neutral" is always your friend. Like many I have witnessed, it took a while for me to understand this. The natural tendency of many is to "drive" the boat into the slip, often with catastrophic results. Learning to relax, shift often to neutral and let the boat take a "set" given the wind and current is much more effective. Neutral and patience. I have seen people 'drive' a boat into a sock. and I do mean DRIVE! They usually were stuck with dock damage fees and kicked out of the marina. |
#4
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posted to rec.boats
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On Wednesday, March 18, 2015 at 6:24:47 PM UTC-7, Tim wrote:
On Wednesday, March 18, 2015 at 6:14:36 PM UTC-7, Mr. Luddite wrote: On 3/18/2015 8:59 PM, Wayne.B wrote: On Wed, 18 Mar 2015 16:14:51 -0700 (PDT), Tim wrote: Yes, at a very slow speed, the boat would back to the left only regardless of how you set the rudder, and that provided to be a royal pain in a few cases. === That issue is known as "prop walk" and it is most apparent at very slow speed before the boat gains momentum. Prop walk is caused by the propellor acting as a paddle wheel. Since the prop/paddle wheel rotation is perpendicular to the center line, a side thrust is created instead of forward motion. The direction of "walk" depends on the direction of shaft rotation. Since your boat is walking to the left we can assume the shaft is rotating counter clockwise in reverse (when viewed from behind the boat). Remember to think of the prop as a paddle wheel at low speed. There are other more complicated explanations for why prop walk occurs but the paddle wheel analogy is the most intuitive to understand and the easiest to apply to problem solving. As Richard pointed out, the rudder has very little effect in reverse until the boat gains some speed and creates water flow past the rudder. This is not a problem in forward because the prop creates plenty of water flow even when the boat is standing still. Backing up a single engine boat is an art form not a science. Every boat is a little different but some basic priciples apply. The best strategy I've found is to apply a quick burst of power in reverse and then shift immediately into neutral. Once you are in neutral there is no more prop walk, and if you have built a little speed, you can steer with the rudder. Sometimes you have to do this more than once. Another strategy is letting the prop walk work in your favor and just let the stern "walk" in the direction it wants to go. This implies some maneuvering room of course. Good explanation Wayne. Yes to both of you. Very good! I think many in this newsgroup are probably familiar with this but it bears repeating sometimes. In cases of close quarter maneuvering, "neutral" is always your friend. Like many I have witnessed, it took a while for me to understand this. The natural tendency of many is to "drive" the boat into the slip, often with catastrophic results. Learning to relax, shift often to neutral and let the boat take a "set" given the wind and current is much more effective. Neutral and patience. I have seen people 'drive' a boat into a sock. and I do mean DRIVE! They usually were stuck with dock damage fees and kicked out of the marina. " 'drive' a boat into a sock" Er... "dock" sorry. |
#5
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posted to rec.boats
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On Wednesday, March 18, 2015 at 6:00:15 PM UTC-7, Wayne. B wrote:
On Wed, 18 Mar 2015 16:14:51 -0700 (PDT), Tim wrote: Yes, at a very slow speed, the boat would back to the left only regardless of how you set the rudder, and that provided to be a royal pain in a few cases. === That issue is known as "prop walk" and it is most apparent at very slow speed before the boat gains momentum. Prop walk is caused by the propellor acting as a paddle wheel. Since the prop/paddle wheel rotation is perpendicular to the center line, a side thrust is created instead of forward motion. The direction of "walk" depends on the direction of shaft rotation. Since your boat is walking to the left we can assume the shaft is rotating counter clockwise in reverse (when viewed from behind the boat). Remember to think of the prop as a paddle wheel at low speed. There are other more complicated explanations for why prop walk occurs but the paddle wheel analogy is the most intuitive to understand and the easiest to apply to problem solving. As Richard pointed out, the rudder has very little effect in reverse until the boat gains some speed and creates water flow past the rudder. This is not a problem in forward because the prop creates plenty of water flow even when the boat is standing still. Backing up a single engine boat is an art form not a science. Every boat is a little different but some basic priciples apply. The best strategy I've found is to apply a quick burst of power in reverse and then shift immediately into neutral. Once you are in neutral there is no more prop walk, and if you have built a little speed, you can steer with the rudder. Sometimes you have to do this more than once. Another strategy is letting the prop walk work in your favor and just let the stern "walk" in the direction it wants to go. This implies some maneuvering room of course. "Backing up a single engine boat is an art form not a science." Yes, I found that out. and quickly. before pulling into a different landing than where my boat was slipped, I figured out in advance how to safely and effectually get out of there without harming other boats or whacking a chunk of dock. Yes, a rudder boat is quite different than IO's. |
#6
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posted to rec.boats
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![]() When I first bought and commissioned the Navigator I was a little nervous about my boat handling skills, especially since I had gone from a 28 footer to a 52 footer. To make matters worse the slip I had in Scituate was right behind a floating fuel dock and I had to back the boat about 150 feet from where I made the initial turn, passing within 10-15 feet of the fuel dock (which often had other boats tied up to it) and into the slip that only had 6 inches of clearance on each side. Fortunately I hired a very experienced tug boat captain to go out with me a couple of times and give me some lessons and tips on close quarter maneuvering. The Navigator was equipped with thrusters but he refused to let me use them. He's the one who really emphasized the "neutral is your friend" concept and taught me to back the boat towards the slip in a series of reverse, neutral, reverse, neutral steps, adjusting as necessary with the shifters (not the throttles) to keep lined up with the slip. It was well worth the short money he charged for these lessons. |
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