Getting Started With the Bowditch Study Materials
The Carry On Mr Bowditch Study Guide is basically a condensed reference built around the American Practical Navigator by Nathaniel Bowditch. It covers navigation methods, celestial calculations, and the kind of coastal piloting questions that come up on captain's license exams. If you are preparing for an OUPV or Master license, this guide lines up reasonably well with what you need to know. The core sections break down into dead reckoning, GPS integration, celestial navigation basics, tide and current tables, and chart plotting. Celestial navigation is where most people stall out. The guide walks through sun sight reduction with form letters and HO 229 tables, which is the standard method the Coast Guard expects. Tidal stream calculations and great circle routing get shorter treatment than the official navigator text, but for exam prep it hits the right beats. I used this alongside the full Bowditch when I was studying for my Sixth Mate exam back in 2019. The guide alone was not enough for the celestial portion. I found myself guessing on intercept calculations during practice tests until I went back to the actual tables and worked through about thirty sun sights by hand. That brought my accuracy from roughly sixty percent up to around eighty-eight percent on timed sections.
How to Actually Use This Guide Effectively
Read it in order but do not skip the plotting exercises. The sections on Mercator sailing and traverse tables look straightforward until you try them without a pencil. I recommend working through every example problem on paper first, then checking your answers against the answer key at the back. The answer key has some typos in the second printing, so cross-reference with the official NOAA sight reduction worksheets when something looks off. The radar plotting section gets used more often than people expect. It covers relative motion, true motion, and CPA/TCPA calculations. For the written exam, you need to know the difference between vector analysis and the arithmetic method. The guide explains both but does not make it clear which one the examiners prefer. They accept either as long as your process is documented clearly on the answer sheet. One specific problem I ran into involved the parallel sailing chapter. The guide gives a simplified formula for departure when sailing along a constant latitude, but the worked example uses a latitude of forty-five degrees and rounds the cosine value too early. That introduced a two-point error in the final distance calculation. I worked around it by keeping all decimal places through the intermediate steps and only rounding at the very end, which is what the Coast Guard grading rubric actually requires anyway.
Where the Guide Falls Short
Electronic navigation coverage is outdated. The section on ARPA radar predates modern integrated bridge systems, and there is nothing on ECDIS or automatic plotting. If you are working toward a license that requires ECDIS competency, you need separate training for that. The celestial navigation chapter is also thin on moon and star sight procedures. It focuses heavily on the sun because that is what shows up most on exams, but in practice you will encounter lunar distance problems occasionally. The tide and current tables assume you have access to the official NOAA publications. The guide references them by number and page but does not reproduce the actual data. That means you cannot complete those exercises without ordering the annual tidal tables separately. Factor in roughly forty dollars and a week of shipping if you are not near a naval supply store or a maritime library.
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Practical Exam Strategy
The written exam gives you about two minutes per question on average. Speed matters more than perfection on the multiple choice sections. I timed myself using only the study guide and finished the practice sets in about forty-five minutes, which left me scrambling on the hard questions during the real exam. Going back and reworking the problems at a slower pace helped me recognize patterns faster. Celestial navigation questions especially tend to recycle the same setups with different numbers. For the oral exam portion, interviewers like to ask about weather routing and heavy weather procedures. The guide does not cover these in depth. I supplemented with the USCG Navigation Vessel Inspection Circular and a few chapters from the Merchant Marine Academy's seamanship notes. That filled the gaps without adding too much bulk to my preparation. Download links for the guide vary depending on whether you are looking for the civilian maritime training version or the Coast Guard approved edition. The CG approved version carries a specific publication number and should be the one you bring to the exam site. Other editions may reference material that has been superseded. Check the Coast Guard's list of acceptable references before purchasing anything online. The page gets updated periodically and older listings sometimes linger on third-party sites.
