Another upgrade question thread


Bowditch will be your only friend in the exam room.

Some things are difficult to learn from Bowditch, but others, including adding and subtracting time, and azimuths and amplitudes are very well explained and readily understandable. Personally, I prefer using the simple tables in Bowditch to solve amplitudes and azimuths instead of memorizing long formulae for the calculator that are prone to button-pushing errors. Even better if you can do it both ways to cross-check.

Bowditch is not the best place to learn the sailings, but once you know them its good to become familiar with the Bowditch method. You’ll have Bowditch to use in the exam room.


Thanks for the input. Bowditch can be somewhat confusing with steps in his formula at times ( lacking explanation about certain parts by assuming we’re all mathematicians ) but once practiced enough I’m seeing the results as well.


What specific calculators are allowed in the exam room? I used a programmable calculator with the memory cleared, are they still allowed?


According to the latest examination guide, only non-programmable calculators are permitted.


The approach I would consider is to purchase and get used to using a good non-programmable calculator that shows the entered formula on the display, like this HP 300S


Assuming that calculator is legal in the exam room.

That approach likely will not work for everyone. Many people prefer using the tables. Like @tugsailor says it’s good to be able to use either one or both but it depends on how much time and patience you have.

Here is a list of non-programmable calculators:


That’s always been the official rule, I’ve been allowed to use programmable graphing calculators on all three sets of exams I’ve done at the REC though.


The official rule is “non programmable calculators” but I’ve always been allowed to use a graphing calculator and I just clear the memory in from of the proctor every morning. I also always take a regular scientific calculator as backup in case the batteries die or they refuse to allow me to use the graphing calculator.


Azimuths require triple interpolation, there’s more error potential there than using the formula. Instead of trying to type the whole formula in just do it piece by piece (round your results to at least six decimal places on each step) and you eliminate button pushing errors.


What formulas do you need that are not in Bowditch Vol 2?


Good point, there’s no need to memorize those formulas on an open book exam.


Fuel conservation / RPM is a formula that comes to mind that I didn’t see in Vol. 01 or 02. Unless I overlooked it, neither were in the index/table of contents.


The discussion is use of the tables or to calculate using formulas. The fuel consumption is not in Bowditch in either form.

I’ve never seen a Fuel conservation / RPM problem on a test so I’m not familiar. The problem I saw were Fuel consumption at different speeds.


The formulas are Merchant Marine Officers Handbook in the chapter on Engineering for Deck officers. I believe they are also inFormulas for Mariners by R. Plant.


We were specifically talking about using the azimuth formula vs using the table.


You should get Lapware, Capt. Joes, Formulae for the Mariner, and the 1981 edition of Bowditch Vol II (you can get it on eBay or maybe as a reprint from a nautical bookstore).

I prefer Lapware for doing the practice exams, but I prefer the solutions in Capt. Joes.

I suggest getting an overview from books and then hiring a tutor for azimuths, amplitudes , and the sailings.


Yes, I see that now. I was speaking in general terms about the the different formulas you will/will not have in bowditch.


Generally only navigation formals are in the books. The fuel burn formulas, slip formula, all stability formulas, etc need to be memorized.


Based on a link @jdcavo provided not too long ago , I’ve seen I may be looking too much into azi/amp and that reason being that on the NC exam ( per CFR 46 11.910 ) azi/amp compass error are the subjects for any body. I also cross referenced it to the NMC sample exam and found their “sample” only asks for compass error questions as well ( gyro error for both). Based on that info, I think I’ve been looking at this subject too broadly rather than condensing into just questions based on compass error.


Okay, I understand now then. I’ll probably move on to memorizing those as I get closer to test day in order to have it fresh on my mind.


Plenty of stuff online for free too. PDF versions of books and even Youtube videos of people doing the problems. A lot of it is really useful.


I found this site particularly useful:

It has a great tutorial on Fuel Conservation Solutions, Azimuth and Amplitude.