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» Online Classroom   »   » Public Discussion of Inland and Coastal Navigation   » Course to Steer

   
Author Topic: Course to Steer
LC Brandt


 - posted January 08, 2007 05:43 PM      Profile for LC Brandt           Edit/Delete Post 
The term "Course to Steer" is used in at least one of the quizzes in the Radar course, but the glossary in the book does not define it. I would like to initiate a discussion of the term, because it is one I find it particularly infuriating.

In the quiz question RC02-34, we are asked to provide Course to Steer, but the apparent correct answer is what I think of as True Course. In another context (elsewhere, not here at Starpath), I have heard the term Course to Steer used as the number that is "handed up to the helm," but that number ought to be what I think of as Compass Heading.

So what is it? When I learned to fly 40+ years ago, before taking my private pilot written exam, my instructor told me write down a simple table, and when solving all nav problems, to fill in all of the blanks of the table before answering any test questions. If I did so, he said, I would never miss another question on an FAA written - ever. And so it proved. Here is the table.

TC_____
Var____
MC_____
dev____
CC_____

Apply wind correction angle, then...
(in the maritime world, of course, we would apply current and leeway at this point.)

TH_____
Var____
MH_____
dev____
CH_____

I think of it like this: "Courses" (true, magnetic or compass) are on paper only, and represent the desired ideal. "Headings" are real world, having had current and leeway, applied. "Compass Heading" is what we fly to - oops - what we steer to at the helm to try to attain the desired (ideal) course.

OK, it's a wordy introduction of a topic, I know. But I am very interested to hear a variety of opinions on this.

(Exception - in some polar nav, and perhaps other special situations, pilots do fly to true, not mag.)

From: Portland, OR
LC Brandt


 - posted January 08, 2007 05:50 PM      Profile for LC Brandt           Edit/Delete Post 
My instructor said that, when facing a nav question on an FAA test, if I always filled in all the blanks of the table before I selected an answer, I would never miss a NAV test question. I've missed plenty of other FAA test questions in my life, so I guess the guarantee doesn't apply outside of the nav arena.
From: Portland, OR
David Burch


 - posted January 08, 2007 09:58 PM      Profile for David Burch           Edit/Delete Post 
We are not thinking of "course to steer" as a technical term... it is just the word course in a sentence. similar to the phrase that might arise such as that is not the "course i want."

It thus does not matter if true or magnetic. if the helmsman steered by a compass, then this presumably would be a compass course, since it would not be fair to tell them something that they had to compute from. if from gyro, it would be a gyro course.

There is also the assumption, if nothing else is stated, that there are no errors to be corrected, and that further it does not really matter in a training practice exercise if true of magnetic, though usually we ask for T or M or R or C or something.

However, we would have to disagree on this being any sort of "heading" or in giving a course to steer and calling it some sort of heading... ie hold this heading. that probably would not be confused, but it could be... especially if they do not hold that "heading" and you have to ask them what is your heading? would he tell you his heading, or would he tell you the number you called a heading? etc.

generally we think of heading as what actually is taking place, not what we necessarily want. what we want is a course. as we try to steer our course, our heading swings around, etc. thus you have electronic "heading" sensors not course sensors.

Good communication is fundamental to good navigation. so we agree that every word should be thought through, but so far i do not see where the use of "course to steer" could cause any confusion. If there is some chance of confusion, then we should definitely address it.

From: Starpath, Seattle, WA
David Burch


 - posted January 09, 2007 09:29 PM      Profile for David Burch           Edit/Delete Post 
A follow up with more examples as i think through our own on the water training courses and the communications between navigator and helmsman.

If the navigator says that the course to steer is 250, then that means that is what he wants the heading of the boat to be at all times, if possible. Thus if the heading drifts off with a wave to 255, the helmsman should bring it back to 250.

with this type of instruction, the helmsman assumes the navigator has figured out any corrections that are needed and so on. He does not think about it, he just does it. This could be a course that the navigator figured to correct for current, and he actually wants to make good a course of 260, and he figures he needs to crab in about 10 to make the course he wants, so asks for 250. So if the only thing he said is "course to steer" the helmsman does just that.

On the other hand, the navigator could have said to the helmsman that "we want to make good a course of 250." This is a common type of communication on our boat. The helmsman would then steer 250 but at the same time watch the COG both digitally and on the echart program. if he is not making 250 by steering 250 he would adjust as needed. if it then seemed stable, he would report back to the navigator that he had to steer say 245 in order to make good 250, and so on, and this would be noted in the logbook.

From: Starpath, Seattle, WA
LC Brandt


 - posted January 11, 2007 02:30 PM      Profile for LC Brandt           Edit/Delete Post 
OK, re communication between navigator and helmsman, the first part of your post defines Course to Steer in a way different from what the question asked for in the quiz, which really was seeking the True Course to take the boat to the entry of the inlet. Current & leeway had not been applied in the quiz question.

I think the Brits use this term frequently, but I think they mean it along the lines that you describe in the second half of your post.

On my boat, typical instructions to the helm might be (a) to maintain a Course as depicted on the chart plotter (say, we want to go south down the 125-55 off the Washington coast), and I let him figure out what heading is required to maintain that Course; alternatively, (b) say we're passing through a critical place in the San Juans that I am familiar with but he isn't, I might say to him to maintain a Heading of XXX.

Both the foregoing examples are specific in intent and use terminologly that has clear meaning.

What I find irksome is the apparent lack of a definition for a term that gets thrown about quite often, and the fact that Course to Steer is an oxymoron. Helmsmen do not "steer" a course...they steer a heading to achieve a course.

I guess if that's the only thing in life I find irksome, then I'm a pretty lucky guy.

From: Portland, OR
David Burch


 - posted January 11, 2007 09:46 PM      Profile for David Burch           Edit/Delete Post 
I believe i see your point, but we tend to follow the terminology of Bowditch, in which a "course" is something you want or steer for etc, something you compute or read from a chart, whereas a "heading" is what you happen to have at any one time. In this sense, if you wish to track along a particular course, you would not steer a heading equal to that course, but you would steer a course and end up with some heading, hopefully equal to your course.

On the other hand, it is perfectly good terminology to say "maintain a heading of... " in specific circumstances, which would often be used in short intervals such as diverting to avoid an obstruction, or swinging the compass, or say checking to see precisely what the cog is... in which case you might want them to lock onto that heading while you read the value of something that depends on your heading. the same thing happens in some radar systems. you want to measure a bearing from the radar with a head-up display (un-stabilized). these depend on your heading, so you could say what is your heading get the answer, and then say hold that heading as best you can for a few minutes.

the official definitions are:

course, n. The direction in which a vessel is steered or intended to be steered, expressed as angular distance from north, usually from 000° at north, clockwise through 360°. Strictly, the term applies to direction through the water, not the direction intended to be made good over the ground. The course is often designated as true, magnetic, compass, or grid as the reference direction is true, magnetic compass, or grid north, respectively.

heading, n. The horizontal direction in which a ship actually points or heads at any instant, expressed in angular units from a reference direction, usually from 000° at the reference direction clockwise through 360°. Heading is often designated as true, magnetic, compass, or grid. Heading should not be confused with COURSE, which is the intended direction of movement through the water. At a specific instant the heading may or may not coincide with the course. The heading of a ship is also called SHIP’S HEAD.

From: Starpath, Seattle, WA
David Burch


 - posted January 11, 2007 10:15 PM      Profile for David Burch           Edit/Delete Post 
i might only add here that we do agree with you that the phrase "course to steer" does not often meet practical needs in the wheelhouse or cockpit, as can be seen from the exmaples given above. What usually has to take place is a longer communication about what you really want to say. The main point of this long response is that communication is likely best if done without referring to a course as a heading.

In the case of the practice problem cited, the wording is "Use your EBL to determine the course to steer midway between the light and the shore."

This could just as well have said "Determine the true course from your present position to a point midway between the light and the shore," but based on the long discussion above, i do not see that there is anything confusing about the wording as it appears.

From: Starpath, Seattle, WA


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