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ccriders 01-14-2008 11:25 AM

Propwalk
 
In another thread it was stated that if you know how to use propwalk you can 360 a boat within a few feet of its length. I sail a 1976 Pearson 28 and have tremendous propwalk, especially in reverse. When I try to back into my slip I have a particularly difficult time actually driving the stern into the slip. I usually just get the stern up to the windward post and then manhandle the boat into the slip, which seems praticularly unseamlike to me. As the wind grows, so does the difficulty of going astern. Does anyone know of a good illustration and discussion of going astern and the issues of propwalk and windage?
Thanks,
John

BarryL 01-14-2008 11:40 AM

It's Hard!
 
Hello,

Backing up straight can be difficult under the best of conditions. Obviously, if you have a lot of room you can get the boat to go straight. It's when the wind is from the wrong direction, and you don't have a lot of room to get way on that's really hard.

My boat, an O'day 35' with a fixed 3 blade prop has a fair amount of prop walk. I try to use that to my advantage when possible. To get my boat to back straight requires that I have her aimed about 30 degrees to port of where I want to go. Then I put it in reverse, rev the engine to 2000 or so, wait 5-10 seconds, throttle down to idle, and shift to neutral. Let the boat move a little, then back into reverse, rev up, wait, rev down, shift to neutral. When the trans is in neutral there is no prop walk. Once I am moving at a knot or so, the rudder becomes effective and I can steer, then I leave it in reverse and move at whatever speed I feel is prudent. I do need 50' or so before I can get the boat to move straight.

The more wind, the faster I need to move so the wind doesn't move the boat faster than I can correct.

All I can suggest is practice practice practice (in an area where you have plenty of room).


Good luck,
Barry

erps 01-14-2008 11:44 AM

Our previous boat had considerable prop walk. Hated it at first but learned to love it. We always planned on tying up on our port side to take advantage of the prop-walk. It did take some planning when trying to back into or out of slips though. If we wanted to back into a spot at our 6 o'clock position, I would have the stern pointing at around the 4 o'clock position when we would start backing down, so by the time we built up enough speed to overcome the prop-walk, we were pointing in the right direction. The 360 degree turn using prop walk was a neat trick that saved my butt a couple of times and amazed some dock walkers who were unfamiliar with the manuver.

sailortjk1 01-14-2008 11:48 AM

Like already has been said, build a little momentum, and than use neutral.
Try to anticipate your moves and use propwalk to your advantage.

teshannon 01-14-2008 12:08 PM

I also use prop walk to get into the slip. It takes practice but once you get the knack of it it's great. The only thing I would add to the posts above is that once I get lined up and start moving into the slip in reverse I'll then shift into neutral and let her coast in if the wind allows. That eliminates further prop walk when you don't want it. I think there was a great little article in Sail magazine about 6 to 8 months ago on how to do a 360 in tight quarters.

GySgt 01-14-2008 12:12 PM

I have to agree with the above, it's all a matter of steerage, prop walk, prop wash and crew on the spring lines. I spent 2 hours practicing backing up Saturday into a slip, and probably will again in a month or so. Like anything, a good crew can make the process easier but, for me anyway, it's all about practicing it.

The fairway turn, or emergency turn uses all 3, Prop walk/wash and steerage. On a boat with prop walk to port, it's a matter of getting steerage, turning hard to starboard, keeping it cranked over and shifting in reverse and watching your bow, when the bow stops drifting to starboard, put it in forward, and when it slows in turning, put it in reverse, ect... until you complete your turn. Practice this in a wide area at 1st so you can see how your boat reacts and you get your timing down. Even on a full keel you can get it to spin around in a short distance, if not totally pivot on the keel. Embarrassingly, I usually use this when I blow getting out of a slip, and the crew was not on top of the spring line and I am pointed in the wrong direction on the fairway because of prop walk, I call it plan "B"

chucklesR 01-14-2008 12:26 PM

CC,
Lots of books out there that have diagrams etc.. it all comes down to starting position, starting angle wind, current and most of all your boat.
Starting angle is the major factor - if you are coming down the fairway going forward and make a right 90 turn to center up your boat between pilings before you back into a slip - change that to a right 50 degree turn, goose it in reverse hard and long enough to get moving astern with the rudder pointed at the left piling of your slip and once you are moving at 1 kt or so astern put center the rudder you should be lined up - wind, current and your own boat make slight adjustments to all that.
Some boats just don't turn to port going aft - for them you have to make allowances and learn new ways.
If you enter the fairway and need to turn to port then back in, instead of a 90 degree turn (centering your boat on the pilings), do it with a 120-130 degree turn, goose reverse and again by the time you are moving astern you will straighten out due to prop wash, just before going straight go to neutral and center the rudder, glide in and there you are.

That's what worked for me on my hunter, on my Gemini the steerable outdrive eliminates that, I just drive it any old which way.
I'm not a photo shopper, or I'd draw pictures.

Sailormon6 01-14-2008 01:38 PM

Barry's procedure is the same as mine. The key is to get enough "way" in reverse to allow the rudder to steer the boat. Then put it in neutral to let the rudder take control. Then put it in reverse to keep it moving into the slip.

I don't consider it at all unseamanlike to manhandle the boat into the slip, especially if you're singlehanding. Backing a boat into a slip is a very complicated process, involving many variables, such as wind strength and direction and currents. Nobody gets it perfect every time. When my timing or handling is off a bit, it doesn't bother me in the least to use a boat hook to grab a piling, or a line stretched between pilings, and pull the boat into the slip. That's what boat hooks are made for, and that's why people stretch lines between their pilings.

ccriders 01-14-2008 05:10 PM

Thanks for your responses. Basically what you suggest is what I'm doing, but it seems inelegant. I've spent serveral days practicing away from the slip and have found that the prevailing wind (SE) will blow the bow down after forward motion is stopped. Then I only have a few seconds under power to get way on aft before needing to go to neutral and steer into the slip (which is on the south side of the fairway). If the wind is not too strong, which is not often, the I can get lined up with the slip and the stern centered on the slip, but normally by the time I get the stern to the pilings, the bow has blown down so that the slip is abeam, at which time i mutter salty sayings and grab the line I've run between the pilings.
Thanks for your inputs
John

teshannon 01-14-2008 05:48 PM

John,
If it's any consolation I have the same problem when there is a stiff wind on the beam, there just is not enough time to make it all happen before you get blown around. Sometimes I'm able to overcome that by giving everything more juice but sometimes even then I'll lose it. When that happens I usually just try to get a spring line on the piling and muscle my way in from there. I'm sure we're not alone and I even see twin screw PBs having the same problem on windy days.


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