# MARS III/IV math requirements



## hawke1759 (10 Dec 2005)

I'm a NavRes NCdt in the MARS trade and I've heard that MARS III/IV are very math-heavy.  My schooling is in History so my math is pretty dismal, so I would like to brush up before I have to take the course.  I've been able to find a bit of information on the MARS III/IV courses, but no specifics as to what I should brush up on specifically in the math department.  Can anyone tell me just what areas of math I should be looking into for the courses?

Cheers


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## Monsoon (10 Dec 2005)

hawke1759 said:
			
		

> I'm a NavRes NCdt in the MARS trade and I've heard that MARS III/IV are very math-heavy.   My schooling is in History so my math is pretty dismal, so I would like to brush up before I have to take the course.   I've been able to find a bit of information on the MARS III/IV courses, but no specifics as to what I should brush up on specifically in the math department.   Can anyone tell me just what areas of math I should be looking into for the courses?


Don't worry - many's the History and Philosophy major now working on full-time class B as a MARS officer on ship.  In fact that seems to be the natural career progression.  The math skills required aren't particularly complex, but the ability to do simple addition/subtraction/multiplication/division in your head (while under pressure) is important for the navigation part of the job.  That being said, all of the skills you need will be taught on the MARS courses themselves, but it would help if you were comfortable with numbers in general before starting out just to make the training a bit easier.


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## hawke1759 (10 Dec 2005)

Thanks Hamiltongs, that puts my mind at ease somewhat.  I wonder why there are so many history majors in the MARS trade?  Probably because we can't get a job doing anything else!


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## Gus (11 Dec 2005)

As Htongs pointed out, the math is generally pretty basic stuff, but when someone is staring at you waiting for an answer it can seem like doing complex calculus.

Here's a few things to get comfortable with:

- getting the reciprocal of a compass bearing.   E.g. - 000 is 180, 090 is 270.   Those are the easy ones; often you'll look through the compass to get a bearing but need to use or report the reciprocal.   Practice figuring those out; one trick that some use is the "Plus two - Minus two" -- for the 090 example it would be "0 + 2" (the first number of 090) to get the 2 of 270, then "9 - 2" (then second number of 090) to get the 7 of 270.   You may find many, or develop one on your own, use whatever works for you; there's all kinds of variations.

- doing simple multiplication or division.   In some cases you need to report the distance a bearing creates relative to range.   For example, at 500 yards 1 degree of compass bearing equals 8.6 yards (some say 8, some say 9 -- it becomes somewhat irrelevant).   How to get that?   Well, one way is to divide 500 by 60 (60 being a "standard" denominator, full explanation would come in your course); another way some use is that at 2000 yards 1 degree equals 33 yards (2000 / 60), and using this as a benchmark one could determine that 500 yards is 1/4 of 2000, so the distance must be 1/4 of 33, therefore = 8 yards (actually a little more, but who's going to quibble about 9 inches at 1/4 mile?)

This might seem a little complicated in writing, but when you sit down a do a few and get comfortable, it comes fairly quickly.   I used to have a whole sheet of this stuff from my instructional days but I cannot find it now, although it would be easy enough to make a new one.   Most of the MARS folks should be able to help you out; but REMEMBER: find the way that works best for YOU.

Good luck.


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## NavalGent (11 Dec 2005)

I got a self study sheet on NETPO this past summer. I find it good for self study. As was already mentioned, it looks intimidating/complicated in this sort of abstract, mathematical setting, but if you want, sit down, work it out so that it makes sense. Its fairly easy to figure out the patterns and what it means. If you're not up for that, you'll learn it during your training. I'm in a Contemporary Studies programme (its not math), and I'm doing fine at understanding these concepts. I haven't done MARS III and IV yet, so I'm not an authority on this stuff by any means, but I figure posting this might help you out. Enjoy! 

Radian Rule - a change of course of x ° will, after y distance get you z distance from your position had you maintained original course.
x ° at y yards/Nm (nautical Mile) = z yards 
1 ° at 300 yards = 5 yards
1 ° at 600 yards = 10 yards
1 ° at 900 yards = 15 yards
1 ° at 1Nm = 33 yards
3 ° at 1Nm = 100 yards
6 ° at 1Nm = 200 yards

6-3-1 Rule - In the time on the left, you will travel the distance on the right, at 10Kts (Knots, or Nautical Miles per Hour)
6 mins = 1Nm 
3 mins = 1000 yards
1 min = 1000'

Regain Track with 3 ° - If you find that you're no longer on the course you plotted on the chart, but you've got the right heading, you can make a 3 ° course alteration port or starboard (wherever you're supposed to be). 
10 Kts regain 100 yards in 6 minutes
13 Kts regain 130 yards in 6 minutes
15 Kts regain 150 yards in 6 minutes

Regain Track with 6 ° - Same as above, but with a 6 ° course alteration. Speed in Kts x 2, with a 0 on the end, and this is the distance that will be regained every 6 mins
10 Kts regain 200 yards in 6 minutes
13 Kts regain 260 yards in 6 minutes
15 Kts regain 300 yards in 6 minutes

Clock Rule (for CPA's) I think it stands for Closest Point of Approach, but it wasn't covered in NETPO. Perhaps another MARS person can help fill us in on what it means. However, I was able to figure out the pattern. Take the degree value of a contact off the bow, and imagine that that value was the minute hand on a clock. So if a contact is 45 ° off the bow, think 45 minutes, which is 3/4 the way around the clock. 

45 ° off the bow = 3/4 dist
30 ° off the bow = 1/2 dist
20 ° off the bow = 1/3 dist
10 ° off the bow = 1/6 dist
15 ° off the bow = 1/4 dist


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## tree hugger (15 Dec 2005)

You could even study ahead WRT rules of the road.  Get those memorized and you will have much more time to focus on the mental math.


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## Gus (16 Dec 2005)

I agree, Collision Regulations holds many people back, and in my experience for two reasons:
1) people don't use the resources available to improve comprehension
2) people study just for the exam, and of course when in the ship they cannot answer even the most basic of questions...good ol' "learn and dump", and to be fair to trainees, most instructors teach it that way.

There is a book you'll get in MARS III (you may see it in NETPO) called "A Seaman's Guide to the Rules of the Road".  It is a British self-study book developed for the Royal Navy.  It is FANTASTIC.  It only covers international rules, not (the silly) Canadian modifications, but the international rules are 80% of the required knowledge.

As I mentioned, it is a self-study/learning package.  It was validated by the RN, and those that used the book, actually read it and completed the exercises in it, scored over 80% (the Cdn Navy pass mark) on exams.  The book, if done from cover to cover, takes the "average" student 6 hours to complete.  It has great examples and explanations and pictures, too.

If you want to wait to get to NOTC to get one, that's great.  But if you don't mind shelling out about $20 for one, order it from Morgan's Technical Books in the UK (i.e. - get your own personal copy).  In my view, worth every penny.  Here's a North American site that supposedly has it   http://www.amazon.com/gp/product/0948254580/qid=1134779336/sr=11-1/ref=sr_11_1/104-0708406-9998305?n=283155

I used this book to help study for the Command Exam on collision regulations - that exam has two sections with 95% and 90% pass marks; that should tell you how useful this book is.


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## hawke1759 (17 Dec 2005)

Gus,
     Thanks for the tip about the "Seaman's Guide"  I looked it up with the link you suggested and ordered it.  I'm probably over-preparing for the MARS training, but it never hurts to be ahead of the game!

Cheers


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## FSTO (18 Dec 2005)

hawke1759 said:
			
		

> Gus,
> Thanks for the tip about the "Seaman's Guide"  I looked it up with the link you suggested and ordered it.  I'm probably over-preparing for the MARS training, but it never hurts to be ahead of the game!
> 
> Cheers



You can never overprepare. Mark my words. Another word of advice, you'll be inundated with electronic aids to navigation such as ECPINS which will make navigation bag of hammers easy. As much as possible stand in front of it and keep your head up and use the Mark 1A Eyeball. The CO and your CTO will absolutely adore you.


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