Identify what the question asks
Write down the required answer first: position, course, distance, speed or time. Under it, list only the information actually supplied. If the question asks for minutes, convert your final answer to minutes before comparing the options.
Check the chart title, scale, symbols and relevant notes. Use a chart with enough detail for the task. A small-scale overview should not be treated as a detailed harbour plan.
Worked example: distance, speed and time
For this study example, a route is 7.5 nautical miles long and the boat maintains a speed over the ground of 10 knots. Assume a constant speed and no stops. One knot is one nautical mile per hour, so time = distance ÷ speed = 7.5 ÷ 10 = 0.75 hours. Multiplying by 60 gives 45 minutes.
Check the result in reverse: 10 × 45 ÷ 60 = 7.5 nautical miles. Then change only the speed to 15 knots. The trip now takes 30 minutes. A higher speed over the same distance should produce a shorter time, which gives you a quick reasonableness check.
Keep chart work and arithmetic connected
A correct formula cannot fix a distance measured between the wrong points. Mark the start and destination, check the intended route, and record the distance before calculating. If the task involves several legs, keep a separate line for each leg.
For a course calculation, distinguish the direction shown on the chart from a magnetic or compass course. Apply only the corrections and assumptions given or required by the exercise; do not invent a missing value.
Build a useful error log
Record the step that failed: reading the position, selecting the route, interpreting a symbol, converting minutes or entering a number. Rework that step with different values. This is more useful than writing down only the correct option letter.
Kartverket's chart-symbol publication contains Norwegian and English terminology. Use it to check an unfamiliar symbol and then explain its significance in the actual chart context. Study examples are not a substitute for updated navigation information before a real trip.
Frequently asked questions
Why is 45 minutes not 0.45 hours?
An hour contains 60 minutes. Divide 45 by 60 to get 0.75 hours; 0.45 hours would be 27 minutes.
Should I learn the example answers by heart?
Learn the method and units. Change one input and solve the problem again to check that you understand the calculation.
Where can I find English explanations of Norwegian chart symbols?
Kartverket's Symbols and Abbreviations in Norwegian Nautical Charts, also called Norwegian INT 1, includes English text.
Official sources
Information checked against these sources on .