Maritime Math revolves mostly around geometry and understanding the angles and distances between known points. Many instruments have been used over the years to estimate these distances and angles, gaining more and more accuracy over the years, now being replaced by computers and satelites. Despite the giant leaps in technology, the math remains very much the same!

Before you get started on these Maritime Math problems, check out these two videos that may help you understand a bit more about maritime navigation!

Problem 1

Q. You are on a ship at sea and want to know how far it is to the horizon. Solve for d in miles using the formula a2=b2+c2 to figure out the distance.

  • H = horizon
  • O = observer
  • h = height of the eye from the sea level
  • 1 mile = 5,280 ft

Problem 2

You are on a ship in the western hemisphere. You observe meridian passage (noon) of the sun at your position. You check your chronometer and note that the time is shown as 1800 hours (6:00 p.m.). But you know that the time you observed was noon, but the time in Greenwich is 6 hours later. What is your estimated longitude?

Problem 3

You want to travel between X and Y. You determine the course to the destination by measuring the angle (or course) from the compass rose on the chart. You measure the distance to the destination and it is 574nm (nm = nautical miles – this term is used in navigation, not statue mile syou use on land). Your ship’s full speed is 15 knots (nautical miles per hour – never knots per hour).

Use the formula D=RT, where D is distance, R is rate or speed, and T is time.

Your customer requires you to arrive between 1500 and 1800 hours on September 15, 2020. What time do you need to leave to arrive at the destination on time, assuming full speed?


CLICK HERE for the answers and instructors key.

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