I find that when backing out of my slip, using reverse, that I am better able to control and turn the stern to the left then to the right. I have a Renault 8 Hp inboard diesel with wheel steering. Could this have something to do with the direction of rotation of the propeller shaft along with the two bladed propeller? I have tried a number of times to turn the boat to the right but it just seems that I cannot get the response and control as when turning to the left. Any thoughts or suggestions? Or is this just the nature of an inboard? Thanks.
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Good ol' prop walk.
Absolutely correct, the boat will walk to port in reverse. One way to correct the problem is to install a very expensive 3-blade prop. This only partially fixes the problem. The cheapest way is to learn how to compensate. Not at all difficult with a little practice.
With rudder in neutral use the throttle to gain adequate speed for steerage. Then put the tranny in neutral before you turn to starboard. The boat will begin to turn to the right if you have enough speed. Once it is moving in that direction simply "goose" it with a return to reverse, a burst of throttle, and right back to neutral. It really helps to have a slip with port side tieup(unless you back in).
Absolutely correct, the boat will walk to port in reverse. One way to correct the problem is to install a very expensive 3-blade prop. This only partially fixes the problem. The cheapest way is to learn how to compensate. Not at all difficult with a little practice.
With rudder in neutral use the throttle to gain adequate speed for steerage. Then put the tranny in neutral before you turn to starboard. The boat will begin to turn to the right if you have enough speed. Once it is moving in that direction simply "goose" it with a return to reverse, a burst of throttle, and right back to neutral. It really helps to have a slip with port side tieup(unless you back in).
Prop Walk In Reverse - Some Boats (Like Mine) Are Worse Than the Norm
From my week-long basic keelboat and basic coastal cruising course last year, we learned about prop walk. (However, with only a week and the various students taking turns, prop walk compensation certainly wasn't mastered very well!) Any book or video on handling a sailboat under power will also have good tips on how to compensate for prop walk and just as important, how/when to use it to good advantage.
Subsequent to my lessons, I found that my 1980 Hunter 36 (bought at about the same time as the lessons) is pretty hopeless at backing out of a slip. The prop walk is so severe that it kicks to port immediately before getting enough speed for steerage. The boat's port stern side jams up against the left side of the slip and the starboard bow swings towards and stays glued to the right side of the dock as I back out. The maneuver looks bad ... and not great for the hull's gelcoat. This kick and twist behavior occurs in any combination of "goosing" it, then neutral, or a steadier low rpm reverse then coast. During a two-hour private lesson with a very experienced sailing instructor, even the instructor wasn't able to back out without brushing up against the dock. The solution has been to have the boat running in neutral with the wheel brake engaged lightly just enought to keep the rudder from moving from the neutral position. Then to push the boat about half way out of the slip to get a little backward speed. Then to step on board to assume my position at the controls. The backward speed now gives me a bit of rudder control, and by then I'm far enough out of the slip that the stern's kick to port won't get me into contact with the dock. Process works great every time ... that is until the day I lose my balance and take a stumble while the boat continues by itself out of the slip. (I sail solo about 50% of the time.)
I'm envious of many of the other boats in the marina. Even inexperienced charter renters seem to just put the gear in reverse and they usually manage to back out more-or-less straight.
The 1980 Cherubini 36's prop shaft angle from the engine, out the stern tube and through the cutlass bearing, is very slight. This results in the prop clearing the hull bottom above it by only an inch or two. I understand that most boats have greater clearance. Water flow from the prop is not straight back. I believe that in a low prop/hull clearance situation, the hull interferes with the top side of the water flow from the prop more than it should as compared to water flow from the bottom side. So the flow is more unbalanced than most boats, particularly in reverse.
I have been planning, as Ed has suggested, to consider switching to a three bladed prop the next time the boat is hauled out. A 3 blade's smaller diameter will give more prop clearance from the hull, and with 3 blades, at any given time two blades will be farther away from the hull. That's my thinking anyway.
Several months ago I picked up a book from the library called something like "101 Things You Wished You Knew About Sailing Before You Bought Your Boat". One of the items listed was that some boats are terrible backer-uppers. I remember that the book cited a model of the Alberg line as an example.
From my week-long basic keelboat and basic coastal cruising course last year, we learned about prop walk. (However, with only a week and the various students taking turns, prop walk compensation certainly wasn't mastered very well!) Any book or video on handling a sailboat under power will also have good tips on how to compensate for prop walk and just as important, how/when to use it to good advantage.
Subsequent to my lessons, I found that my 1980 Hunter 36 (bought at about the same time as the lessons) is pretty hopeless at backing out of a slip. The prop walk is so severe that it kicks to port immediately before getting enough speed for steerage. The boat's port stern side jams up against the left side of the slip and the starboard bow swings towards and stays glued to the right side of the dock as I back out. The maneuver looks bad ... and not great for the hull's gelcoat. This kick and twist behavior occurs in any combination of "goosing" it, then neutral, or a steadier low rpm reverse then coast. During a two-hour private lesson with a very experienced sailing instructor, even the instructor wasn't able to back out without brushing up against the dock. The solution has been to have the boat running in neutral with the wheel brake engaged lightly just enought to keep the rudder from moving from the neutral position. Then to push the boat about half way out of the slip to get a little backward speed. Then to step on board to assume my position at the controls. The backward speed now gives me a bit of rudder control, and by then I'm far enough out of the slip that the stern's kick to port won't get me into contact with the dock. Process works great every time ... that is until the day I lose my balance and take a stumble while the boat continues by itself out of the slip. (I sail solo about 50% of the time.)
I'm envious of many of the other boats in the marina. Even inexperienced charter renters seem to just put the gear in reverse and they usually manage to back out more-or-less straight.
The 1980 Cherubini 36's prop shaft angle from the engine, out the stern tube and through the cutlass bearing, is very slight. This results in the prop clearing the hull bottom above it by only an inch or two. I understand that most boats have greater clearance. Water flow from the prop is not straight back. I believe that in a low prop/hull clearance situation, the hull interferes with the top side of the water flow from the prop more than it should as compared to water flow from the bottom side. So the flow is more unbalanced than most boats, particularly in reverse.
I have been planning, as Ed has suggested, to consider switching to a three bladed prop the next time the boat is hauled out. A 3 blade's smaller diameter will give more prop clearance from the hull, and with 3 blades, at any given time two blades will be farther away from the hull. That's my thinking anyway.
Several months ago I picked up a book from the library called something like "101 Things You Wished You Knew About Sailing Before You Bought Your Boat". One of the items listed was that some boats are terrible backer-uppers. I remember that the book cited a model of the Alberg line as an example.
Try This
Have heard it recommended to release all docklines except for a backspring which is made up as a slip.
Then select reverse and run the engine hard so that the prop is pulling lots of water over the hull and rudder from astern. The boat thinks it is going backwards through the water!
Next reduce the stern power and slip the spring.
This will enable steering in reverse at a much lower speed over the ground.
Never tried it myself (no need to) but would like to know if it actually helps.
Regards,
Have heard it recommended to release all docklines except for a backspring which is made up as a slip.
Then select reverse and run the engine hard so that the prop is pulling lots of water over the hull and rudder from astern. The boat thinks it is going backwards through the water!
Next reduce the stern power and slip the spring.
This will enable steering in reverse at a much lower speed over the ground.
Never tried it myself (no need to) but would like to know if it actually helps.
Regards,
Use a spring line
My 27' has a lot of prop walk to port also (with a 3 blade prop). Depending on your slip you can use a long spring line tied to the toe rail about 8' to 10' back from the bow on the starboard side to turn you. Give the other end a couple of wraps on your winch and drop it over the last cleat on the dock. As you start backing out the line will catch on the cleat and will turn you to starboard perfectly. Let the line off the winch (engine in neutral at this point) and then retrieve it. It works great. Same technique works for backing into a slip.
Manny
My 27' has a lot of prop walk to port also (with a 3 blade prop). Depending on your slip you can use a long spring line tied to the toe rail about 8' to 10' back from the bow on the starboard side to turn you. Give the other end a couple of wraps on your winch and drop it over the last cleat on the dock. As you start backing out the line will catch on the cleat and will turn you to starboard perfectly. Let the line off the winch (engine in neutral at this point) and then retrieve it. It works great. Same technique works for backing into a slip.
Manny
Russel the h27 Cherubini lives up gallantly to its
reputation for being among the top contenders for the all time award of the worst mannered boat for backing up. You are correct, the rather large two blade prop is largely to blame. The good thing is that the behavior is predictable and you can master it and even use it to your advantage when manuevering in close quarters. To back out of a slip use your starboard stern dockline or a spring line to restrict movement to port while allowing movement in reverse. You can hold the line in one hand and release it when the boat gains steerage. Once you gain steerage shift into neutral as there is no prop walk in neutral. Alternate between reverse and neutral as you back out. I have always preferred to use idle speed as it allows for a slower paced procedure with lesser tugging forces. The admiral likes it nice and easy. It also allowed for shifting the transmission without having to worry about the throtle lever. There are exceptions as when current or wind are pinning you down you will need to power out. One of the advantages of the marked prop walk on the h27 is that it helps you to turn the boat around on its axis. Gain momemtum forward and turn the wheel full to starboard, as the stern swings out to port shift into reverse and let the prop walk continue to bring your stern around without the boat inching forward. I was once in a river marina and when it came time for departure I noticed a strong current. There was no way I could get the boat to reverse to starboard so I let it slide to port and now I'm facing the dead end of a narrow fairway. Rather than backing up for 100 yards I powered forward and turned it on its axis just using enough throtle to counter the current. Also when tying up to a dock on portside you can just get your bow up the dock position and shift into reverse and watch that stern just tuck in. Sometimes I now miss the prop walk of the 27. Practice, practice.
reputation for being among the top contenders for the all time award of the worst mannered boat for backing up. You are correct, the rather large two blade prop is largely to blame. The good thing is that the behavior is predictable and you can master it and even use it to your advantage when manuevering in close quarters. To back out of a slip use your starboard stern dockline or a spring line to restrict movement to port while allowing movement in reverse. You can hold the line in one hand and release it when the boat gains steerage. Once you gain steerage shift into neutral as there is no prop walk in neutral. Alternate between reverse and neutral as you back out. I have always preferred to use idle speed as it allows for a slower paced procedure with lesser tugging forces. The admiral likes it nice and easy. It also allowed for shifting the transmission without having to worry about the throtle lever. There are exceptions as when current or wind are pinning you down you will need to power out. One of the advantages of the marked prop walk on the h27 is that it helps you to turn the boat around on its axis. Gain momemtum forward and turn the wheel full to starboard, as the stern swings out to port shift into reverse and let the prop walk continue to bring your stern around without the boat inching forward. I was once in a river marina and when it came time for departure I noticed a strong current. There was no way I could get the boat to reverse to starboard so I let it slide to port and now I'm facing the dead end of a narrow fairway. Rather than backing up for 100 yards I powered forward and turned it on its axis just using enough throtle to counter the current. Also when tying up to a dock on portside you can just get your bow up the dock position and shift into reverse and watch that stern just tuck in. Sometimes I now miss the prop walk of the 27. Practice, practice.
My H28.5 will also
"walk" to port in reverse. Here are a couple of suggestions, which may or may not be useful depending on your slip/fairway configuration. Center the rudder, and begin to back out in a straight line. Once about half of the boat is out of the slip and you have a bit of speed, then turn the rudder in the direction you want. I have found that turning the rudder without boatspeed will often stall the rudder once you add power.
Secondly, it would sound like you could take advantage of your prop walk by backing into your slip -- then you would have no problem leaving it.
I used to have slip at my marina that faced south and so I had to work against my prop walk to back the boat out to starboard in the fairway. I changed slips to one that faces north and so now the prop walk works for me nicely when backing out.
Finally, every now and then when I'm alone and there is a crosswind pushing the stern of my boat the "wrong" way when attempting to back out, I go with the flow and simply back out the entire length of a relatively short fairway. This always produces some strange looks from onlookers, but it gets me where I want to go and without dinging up my boat, or other boats. Whatever works, works....
"walk" to port in reverse. Here are a couple of suggestions, which may or may not be useful depending on your slip/fairway configuration. Center the rudder, and begin to back out in a straight line. Once about half of the boat is out of the slip and you have a bit of speed, then turn the rudder in the direction you want. I have found that turning the rudder without boatspeed will often stall the rudder once you add power.
Secondly, it would sound like you could take advantage of your prop walk by backing into your slip -- then you would have no problem leaving it.
I used to have slip at my marina that faced south and so I had to work against my prop walk to back the boat out to starboard in the fairway. I changed slips to one that faces north and so now the prop walk works for me nicely when backing out.
Finally, every now and then when I'm alone and there is a crosswind pushing the stern of my boat the "wrong" way when attempting to back out, I go with the flow and simply back out the entire length of a relatively short fairway. This always produces some strange looks from onlookers, but it gets me where I want to go and without dinging up my boat, or other boats. Whatever works, works....
Here's a site with some animations
Some helpful info for maneuvering at the dock here: http://www.cruising.sailingcourse.com/docking.htm
Some helpful info for maneuvering at the dock here: http://www.cruising.sailingcourse.com/docking.htm
Backing and Props, Etc.
I have spent the past two seasons frustrated with problems such as vibration, severe prop walk, and low engine RPM at cruising speed.
I do not know the origin of the prop that was on the boat ('81 H30) as there were four POs. I had the Prop reconditioned this past spring and found out the pitch as it was unmarked. Consultation with Hunter Tech Support led me to General Propeller and Yanmar. They agreed that my prop was over pitched by 6 inches! I bit the bullet and changed to a 15 x 10 3-blade "Sailor."
I now have a new boat, it backs up either way, cruises well at 80% of full RPM, will reach full RPM, etc.
All of the info n this thread is valid, however a proper prop is critical.
I have spent the past two seasons frustrated with problems such as vibration, severe prop walk, and low engine RPM at cruising speed.
I do not know the origin of the prop that was on the boat ('81 H30) as there were four POs. I had the Prop reconditioned this past spring and found out the pitch as it was unmarked. Consultation with Hunter Tech Support led me to General Propeller and Yanmar. They agreed that my prop was over pitched by 6 inches! I bit the bullet and changed to a 15 x 10 3-blade "Sailor."
I now have a new boat, it backs up either way, cruises well at 80% of full RPM, will reach full RPM, etc.
All of the info n this thread is valid, however a proper prop is critical.
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