How Japanese Pilots Navigated The Ocean In WW2

How were Japanese Navy pilots able to navigate back to their carriers during WWII?  Japanese carrier pilots often don’t have radios in their aircraft because of weight and reliability issues. They have to rely on simpler methods instead. These methods are widely used in aviation all over the world if there’s a lack of radio navigation aids.

First Method

The first method was known as dead reckoning. This is a navigation method that calculates one current position using a previously determined location and advancing that position based on known or estimated speeds over elapsed time and course.

The main tools used for dead reckoning are a compass, a chronometer, an airspeed indicator, and navigational charts for plotting courses and recording positions. Pilots would start with a known starting point and then use their compass to maintain a constant heading. They would then record their speed, as well as the time traveling in that particular direction to plot their current position relative to the starting point.

One of the most common issues to the aircraft carrier was that it was in constant motion and its position may have significantly changed. Another challenge is the wind drift that causes the plane to deviate from its intended course, which can lead to significant navigational errors. Pilots often use meteorological reports and their in-flight observations.

Second Method

The other method is known as celestial navigation. This involves using celestial body positions such as the sun, moon, stars, and planets. The sextant was the main instrument used in this method allowing the observer to measure the angle between a celestial body and the horizon.

The observer often uses this instrument and looks through the telescope at the horizon. The index mirror reflects the image of the celestial body to the horizon mirror. The observer then moves the index arm until the celestial body’s reflected image lines up with the horizon as seen through the telescope.

As soon as the celestial body is aligned with the horizon, the angle between them is then read from the graduated arc. The angle, along with the exact time of the observation is used to know the observer’s position using celestial navigation tables.

Specialized bubble sextants are often designed for use in aircraft allowing stable measurements even while in motion. Japanese pilots often use the Set39, a copy of the American Army Corps Sextant A8.