GPS Convertor – This Microsoft Excel spreadsheet will convert between WGS84 and AUS66 GPS datums.  Failure to plot on the correct datum could cause errors of hundreds of metres.

Water Depth Calculator – Maritime charts include information about water depth at various locations.  However, this depth fluctuates with the tide throughout the day.  This Microsoft Excel spreadsheet is used to calculate the water depth at a particular time based on chart depth and the ‘rule of twelfths’.  Will only show depth up to 15m, which should be sufficient for all small vessels.  It should also be used as an estimating tool only.  A safety factor should always be included when boating in shallow waters.

Currents and Temperatures – This Google Earth file shows prevailing currents and sea temperatures off the east coast of Australia.  Current as of 17/12/2008.  (Source – CSIRO).

Compass Deviation Card – This card is used to allow for errors in the ship’s steering compass when navigating by hand. Almost every compass has some degree of error which changes throughout the ship’s life and the earth’s surface. A new deviation card should be completed annually or when navigating in vastly different locations.

Beaufort Wind Scale – This document outlines the description for the Beaufort Wind Scale. Although not officially used in weather forecasting, it’s a useful document to refer to when entering data in the ship’s log or describing the weather.