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-   -   My Boat Won't Back (in a straight or controlled line) (http://www.sailnet.com/forums/general-discussion-sailing-related/72147-my-boat-wont-back-straight-controlled-line.html)

NCC320 02-18-2011 08:30 AM

My Boat Won't Back (in a straight or controlled line)
 
Over the last few years, I've seen lots of posts with this or similar complaint. And, I've watched people struggle at backing into slips, even when the boat will back fairly well. Some boat designs may not back well, but I would like to suggest a slightly different technique which might make you happier with your boat.

I may be suggesting something that will not work, but try it and maybe it will.
When I was negotiating to buy my boat (Catalina 320), I went to a boat show to see a competitive boat. The Catalina dealer had single handed a new Catalina 42 into a tricky docking arrangement at the show docks. I inquired how he was able to do it. He said that it was easy. The trick to controlling in reverse is to get the boat going. Once you get sufficient speed in reverse, the boat responds to the rudder in going backwards. just like it does going forward. It looks neat to drive in just past your slip in the traditional manner, turn away, then throw engine in reverse and back into the slip. To do this consistently, you have to know your boat well, adjust for wind, current and other variables. But you don't have to do it this way (at least not on my boat and the C42). Nearly all boats have prop walk...it has to do with the geometry of the prop, the surrounding boat and discharge stream of water (if the discharge is up and against the boat, and forward, then you get significant walk --- you get prop walk going forward, but the discharge is more into the rudder and away from the boat, and you just don't notice it as much because you correct for it with the rudder).
The dealer said, don't worry about prop walk. Well away from the dock, put the boat in reverse, increase power gradually, and get the boat moving in reverse. Gradually increase throttle and speed so that eventually the rudder takes over and controls the boat direction inspite of the prop walk. Keep the speed above this level, and just drive the boat in reverse. The dealer said that he just stood in front of the wheel and drove the zig zag course necessary to get into his slip. This is the technique that I use now. It looks a little strange because I will back down a long fairway and simply drive down, and turn into the slip going backwards. If you have a line handler forward, you can dock without even touching the pilings. If there is a crosswind sufficiently high, or going downwind, I have had to abandon this techique on occasion and dock bow first, but otherwise, it makes docking really easy. Once you start into the slip, lock the wheel brake down to prevent damage to the rudder (it can slam into the stocks if not restrained). You lock it down just enough to hold the rudder, but so you can still override the brake to control the rudder in docking. My C320 is a wing keel and is really quite maneuverable, so I'm sure that it's easier for me, but I believe many of you who say your boat won't back, it may be because you haven't tried this technique. If you try it in open water, you'll not damage anything and you'll learn if it is possible. And if your boat really won't back using this technique, then learn the back and fill technique that power boats (with small rudders) typically use. In regards to locking the wheel/rudder with brake, don't do this until you are nearly in your slip, because you loose rudder/wheel sensitivity and can't respond to wind shifts well unless you have the sensitivity. Also, many boats (mine anyway) will lay beam to the wind if you just let it go. Before you start trying to back, put the boat in this position relative to the wind. If you try to head into the wind, like you would if you are dropping your sails, the wind, the boat's natural tendency to fall off beam to wind, and prop walk will conspire to spin you around and out of control. Putting the boat in the position where it naturally wants to go, minimizes this tendency. If the boat is going too fast when you approach your slip, simply shift momentarily into forward to check your speed, but not long enough to stop the backward movement and rudder control. Also, you can shift alternately in and out of gear to control your speed. And going backwards first, if you need to abort, shift into forward and hit the trottle. You'll be surprised how well you can get out of a messed up approach. And if you do miss the approach, don't try to correct. It's going to get screwed up. Abort, go out and start again. Good luck.

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rayncyn51 02-18-2011 08:53 AM

We use basically the same technique with our Catlaina 30. Once she is moving in reverse, I have complete confidance that she will go exactly where I point her.

When making the transition to reverse, I steer about 20 feet to the right of the line I want to steer in reverse, then take off the last forward speed with a shallow left turn, leaving the boat about 30 degrees to the expected direction of travel in reverse. Once in reverse, slowly increasing throttle pulls the stern to the left and back in line with the intended direction of travel. As water starts to flow under the boat, a little left wheel helps to couteract the prop walk. The swing slows, the boat moves backwards, and after that, it's just driving.

We used to have some real docking disasters trying to reverse and back into the slip from the fairway. Now we reverse in the basin, back all the way down the fairway, and turn right into the slip.

rmeador 02-18-2011 09:35 AM

I've only docked stern-first once, and it was quite frightening. I noticed that my boat will steer in reverse if it is going fast enough, but the turning radius is terrible. There's not nearly enough space for me to use that technique to get into my slip. The trick I used in my trial by fire was to put it in reverse at high throttle until I get moving, then give it a quick burst in forward with the wheel turned hard in the way I want to go (actually I think it might be the opposite way... I do it automatically). The burst of forward causes the stern to quickly swing without killing the backwards momentum. It's almost like a stern thruster. Since this has to be done multiple times, I don't even bother straightening the wheel before going into reverse again, since at this low speed the rudder has nearly no effect.

sailingdog 02-18-2011 10:11 AM

Rmeador—

Most boats will turn quite tightly in one direction and horribly in the other... you might want to take you boat out and see what the case with it it. Sometimes, doing a 270˚ turn is easier than doing a 90˚ one.

Sabreman 02-18-2011 10:13 AM

We've used the same technique for years and you are correct that the key is to get the boat moving. I will also note that when we switch from forward to reverse, we use significant throttle to stop any remaining forward motion and to get the boat moving in reverse. My wife has a tendency to forget to throttle up when in reverse, so I gently remind her beforehand that idling in reverse is useless.

Another tip is to make sure that the engine is in neutral before switching to reverse. Shifting directly from forward to reverse can kill a transmission. We coast parallel to the slip and while making the 90 deg turn to back in, bleeding off forward speed. Only when we're lined up with the slip (offset to starboard 1/2 boat width to account for prop walk) do we put the boat into reverse.

I do not like to stand in front of the wheel facing aft because then all the engine controls are reversed and it's hard for me to reach the shifter and throttle. I prefer to face forward and look over my shoulder. Just remember to turn the wheel in the direction that you want the stern to go. For tillers, point the aft end of the tiller where you want the stern to go. It's that easy.

sailingdog 02-18-2011 10:46 AM

Also, you really have to make sure that the boat is making way in reverse before turning the wheel or tiller. If you're not actually moving backwards, the boat is not going to go where you want it to.

NCC320 02-18-2011 12:54 PM

One other thing,

Lots of boats are geared such that in reverse, the maximum prop rpm (i.e. at maximum engine rpm) is less in reverse than in forward. In my boat, maximum prop rpm is only 75% of forward rpm. So when, one shifts to reverse, you really need to apply lots of power. It'll sound like something should be happening with all the noise, and it will eventually. Just be patient because there is a big argument going on between the prop and rudder as to who is going to be in control. If you have much forward speed on when you go to reverse, this is going to take a bit of time, but eventually the boat will start to move in reverse. Until these forces resolve the situation, it's better to just keep the rudder admidships. Putting on lots of rudder until the boat is moving, is just going to cause the rudder to act as a brake against that initial backing movement and aggrevate the prop walk issue. And don't worry about the boat walking around. Once you get moving, you can correct this with the rudder. That's one of the reasons to start this process outside the fairway, where you could conceivably get into a position that you can't get out of. Outside, you don't have to worry about it. And also, you don't have to worry about where current and wind are moving you before backing movement is established.

Faster 02-18-2011 01:11 PM

Part and parcel of 'getting the boat moving' is resisting the impulse to put the helm over for the turn before steerage is attained... doing so simply puts the brakes on and increases side motion in many cases.

Keep the rudder centered until it will actually do something for you.

Also, once you know how much propwalk rotation you'll experience, simply point the boat at an angle such the the propwalk will straighten you out about the same time you start moving and having steerage.

All that said, though, there ARE some (actually many)designs that will not respond to any of these techniques. A short cord fin/spade rudder is always going to do OK in the right hands

Boasun 02-18-2011 01:45 PM

A new type of race: Backing a single screwed boat around salom pilings and the fastest times. Lets say a two mile distance overall.

jackdale 02-18-2011 01:48 PM

Once you get the boat going with sufficient speed to maintain steerageway; you can eliminate prop walk by putting the transmission in neutral.


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