boat direction in backing

[robryan]

Just started sailing a CD31. notice the following when docking putting boat in reverse the stern goes port. However if not docking just putting the boat in reverse in open water the stern goes starboard. this makes no sense. I was with a captain with 30 years sailing experience, still acts as a captain on 9 different sail boats from 36-50 foot all a different boat. and he could not figure it out either.

We lost linkage on the transmission from the cockpit 2 days ago the transmission was in reverse when a bolt came loose and the boat was in reverse. only went in a starboard circle could not change direction even after more throttle.

last night coming into a marina I wanted to practice neutral, reverse before trying to dock. so a 100 or so feet before docking i put it in reverse and the stern goes starboard. get to the dock bow closer to dock want to move the stern closer to port side dock, put in reverse the stern moves port just as planned. What is going on?

Again I am new only had a typhoon with a outboard. But again the person helping me learning to sail this boat has many many years experience on many types of sail boats and is still sailing 9 different ones.

[Jeff and Sarah]

There could be some wind or current issues at play near your slip. You might not see this issue persist as you enter the dock at different times/weather conditions.

For what it's worth, I have found a good way to partially mitigate the turning effect in reverse is to use very momentary shots of reverse (at enough RPM to start the rearward travel) followed by immediately placing the transmission back in idle. This limits the time you apply torque and often lets you have more control over which way the vessel backs using the rudder.

[robryan]

Thanks for the reply. This has happened in 2 different marina's in open water lake superior in a area protected from wind ( happened while anchoring close to shore) we put it in neutral and then reverse.

I will try what you said to try. maryland school of sailing talked about higher RPM for a few seconds reverse neutral to get movement over the rudder. we had movement over the rudder when the bold let loose but could not steer the boat. we wre going to try an back the boat a couple of miles to a marina (since it was in revers and we could not change it unless we were willing to crawl over a hot engine to change direction and we had nothing to lay over the engine even if we knew what to look for after we did.

Thanks for the reply

[Astronomertoo]

The basics are: (Someone tell me if I have this wrong)
Given any full keel vessel like the CD, with a right hand rotation prop for forward gear (counter clockwise for reverse), and with the prop in an aperture between the keel and the rudder, anytime you put the prop in reverse gear, you will be getting the paddle wheel effect (moving the boat stern sideways) until you have boat motion in reverse, and then the rudder becomes effective for steering in reverse. You can count on this for close maneuvering when you get used to it. If you have motion in forward or reverse with water flow past the rudder, the "prop walking" is a minor effect. Therefore if you want steerage control in reverse for backing out of a situation, you must have water flow past the rudder, so you must get it moving quickly. Idling will not do it.
Likewise, if your prop is fouled up with crud you are not going to make thrust, but it will still cause you to "walk" side ways with no, or minimal directional motion.
You can practice these motions, out of your slip out in the open, ie, near a fixed pole or marker, to practice the effects, and learn how much thrust and motion you need to enable rudder control in reverse. As soon as you get that motion you can idle down the engine and use the rudder. With practice you can get motion quickly, pull the power back, and idle in reverse with tolerable control. Try doing slow figure eights in reverse, and forward approaches to the pole on both sides, and then stopping, AWAY from witnesses. Quick short bursts of power can be your friend.
In the case of using an outboard motor on the stern or in the well of a smaller cape dory, with the motor on a bracket behind the rudder, the result is different because the reverse prop wash of an outboard on the turned rudder will move the stern positively in the direction the rudder is turned as soon as the prop wash hits it.
Basically, in all cases, you must have motion "way" of the boat before the rudder can be effective for steering.
At least that is the way it works for me.
Having had a fin keel boat with a spade rudder for 6 years I can tell you that they steer 10 times better in slow motion and in reverse than our Cape Dorys. Needless to say we get to have fun while developing our skill at close handling.

[robryan]

Thank you for your reply. that is also my understanding. I will try again at a faster speed.

[Capt Hook]

BobC,

Thanks for that explanation. I too am a (relatively) new CD 31 owner still trying to figure out the steering in reverse thing.

I should probably go out to the open area in the marina and practice backing up, like you said AWAY from witnesses.

[wsonntag]

The mysteries of steering a CD31 in reverse! They will kick the stern to port, wheel walk with a blast of throttle especially when coming along side something to port, but beyond that its simply anyone's guess. Over 20 years of sailing a 31 you put her in reverse and then you get to see which way she's gonna go. If you stay in reverse, get up some speed, you generally can get her to steer, but short distances, like backing out of a slip, well fifty percent of the time you look like you know what you're doing, fifty percent you look like a fool. Cardinal rule, if she starts going the wrong way and you're going to be put in a difficult situation, stop, don't try to force it, tie back up or pull away, start again. I managed a tricky back-in docking maneuver with green crew a few weeks back, but only on the third try. The boat yard crew were all standing around looking judgmental, so what, tough I say better than tangling with an anchor on a bowsprit or a nasty scuff from a piling etc. When departing some exotic clime and things go awry, if you have to, pull back into the slip, jump off, declare someone forgot the beer and ask your crew on deck "one sixpack or two?!"

[mashenden]

I know its rhetorical but "two"... 2 is the answer. As far as why port vs starboard but only when at the dock...