Where does a boat turn?

[Brian D]

As I was moving my boat today, I was wondering when I execute a turn, where does the boat turn?When a car turns, the turn is under the wheels. The opposite end follows. But on a boat, I don't think that is happening.Does the boat turn under the keel, at the rudder, or forward at the bow? When the boat starts a turn, is it really pivoting or is it sliding thru the water at an angle? Is the boat turning at the mast step?So, when a boat turns, where does it turn?

 

[steves22278]

Turning

If you have a fin keel boat, the boat sort of pivots about a point about 1/3 of the keel chord aft of the leading edge of the keel. This is why you have to watch your bow and stern when you turn, especially in tight quarters.

 

[David]

Try this

Next time you're out, come to a full stop; put your rudder hard over and throw the throttle forward for about 1 to 2 seconds. The thrust will kick water against the rudder, and your boat will pivot around its natural turning point. If you are looking at a fixed point (dock or piling) you will be able to see just where the fulcrum is.

 

[Brian D]

Alas...

I have an outboard. But the O/B is fixed like an inboard. I do not move the O/B to compensate turning. Will I still get simular results?

 

[Dan McGuire]

Similar to a Car

The center of a turn for a car is at right angles to the wheels. This of course, disregards any slippage, but is generally true. The conditions are similar for a boat. The center of the turn is perpendicular to the keel and the rudder. Again this disregard any sideways movement of the rudder or keel through the water, but generally works.

 

[Benny]

In reverse or going forward?

Your question sounds rethorical, as you probably know that the interaction of boat speed and direction, wind strenght and direction and current strenght and direction plus a number of other minor factors determines how a boat turns.Stern drift, prop walk, windage, wind, current and engine power are factors to be contended with when manuevering in close quarters. A boat can turn on its axis or not at all depending on the variables. A line tied to a dock will establish a pivot point at the point of attachment. The things that will help us steer a boat are constants and the theorical pivot point is not one of them.

 

[Benny]

Brian, I had missed your comment that

you have an outboard. You have a situation of those minor factors I was referring to. An inboard driven boat can create water flow through the rudder to induce stearage a lot quicker than you can. On the other hand you do have the ability to direct water thrust by swiveling the motor head. Make sure the engine lower unit and the rudder are turned in the same direction and not fighting each other. You can reduce stern drift by increasing power but get to know your boat so you will learn the handling limits.

 

[sailortonyb]

Turns at the stern

Actually , what really is happening is the stern of the boat is moving in an arc and the bow just gets re-pointed (dont think there really is such a word) in a new direction. That is why if you try to turn at a buoy in a channel, you end up turning too short. Unlike a car where the front turns and the back follows.

 

[Franklin]

Yes....

The rudder forces the stern one way or another but the keel is the point of turn. AKA...a boat pivots on the keel. The pivot is force by the rudder swinging to avoid the pressure agaisnt it.

 

[Brian D]

Benny, the O/B is fixed

and located at a point where I cannot swivel it in the direction of my turn. So I must assume that when the cavitation is moving toward the bow (I was in reverse), the rudder is deflecting the water in another direction. I believe cavitation is a correct term, at least I hope. I noticed that when I started my turn this morning (while going in reverse) the boat did not turn right away. I have become aware of this fact.Granted, I need more practice. Thanks guys.

 

[Joe]

turning your sailboat.

Franklin's comment is correct in that essentially the sailboat with a fin keel will pivot on that appendage. Yachts with longer full length keels will not turn as easily as the fin or bulb keel. For that reason, full keels are very popular on cruising boats where maneuverability is not as important as directional stability. Brian, "Cavitation" is the the wrong term. "Prop Walk" is the phenomenon you're describing. When backing up, the prop will dramatically pull the rear of the boat in its direction of spin. You can use prop walk to your advantage to help turn the boat in tight quarters. Try this next time you're out in a quiet corner of the harbor: If your prop walk pulls the stern to the left, use it to make a tight right hand turn by pushing the tiller over, then gunning the throttle in forward for a few seconds to to get the turn started. Once the turn starts, push it back in reverse for a few seconds, the forward motion will stop but the prop walk will keep pulling the stern to the left. Again, shift back into forward for a few seconds then back to reverse. Keep repeating this sequence a few times and you should be able to rotate your boat nearly within its own length. You'll come away from this exercise with a greater understanding of how your boat turns and more importantly, a feeling of confidence in your ability to maneunver your vessel in close quarters. You can use the prop walk in other ways. Grab a copy of Chapman's or Annapolis Seamanship to learn more. Have a blast.

 

[Brian D]

Thanks Joe, and everyone else...

I have Chapman's but there is little on the subject that I found in the book.

 

[Joe]

Brian D..... some more help for you.

Brian... here are a few links to the US Sailing online course sections that deal with docking and maneuvering. One from the basic keelboat course and one from the cruising course. They should be of some help. Enjoy.http://www.sailingusa.info/anchors_and_docking.htmhttp://www.cruising.sailingcourse.com/docking.htm

 

[Brian D]

Thanks Joe

I ran across those sites along time ago. I forgot about them. Good info to have. I think I may have tried a pivot turn but it didn't work. I'm sure I wasn't doing it right, or maybe the OB responds differently than an IB.

 

[Joe]

works with an outboard....

...as long as you have a fin keel. It's near impossible with a full length keel. My C27 has a 9.9 Tohatsu OB. Since the motor has no tiller arm I leave it in fixed position, but I can still turn pretty tight. The prop walk has a lot of leverage since the OB's at the extreme end of the boat.

 

[Stu Jackson]

Brian

the next weekend is fast approaching.Take your boat out again.Lock the motor in a centered position.Go try different things out.All of this theorizing is making me take my boat out daily just to try them all out.

 

[LloydB]

So,

when a car turns on ice, where does it turn?

 

[sailortonyb]

So

If a boat turns in a forrest, does anyone see it turn?

 

[Franklin]

ask the idiot who put it there

he should know

 

[tweitz]

where you turn

The most important thing about where a boat turns is that it is at or towards the aft portion of the boat. Which means if you are next to a dock, you can't just point your nose, like you do in a car. If the dock is on your port side, and you go forward and steer to starboard, you will hit the dock on your port side, in the aft section of the boat. So you may want to back away.