Ocean Passages
You are planning a long sailing boat voyage, a delivery trip perhaps, or maybe a long leg of an extended cruise. Your boat is not a speed machine and you expect to be at sea for a week or more and need some idea of when might be the best time to start such a voyage and which would be the best route to take. The great circle route between two points on the earth’s surface is not necessarily the quickest route or the most economic or the most comfortable. Time spent route planning is not wasted and may make the difference between arriving with a fresh happy crew or with a boat that has taken a beating and crew that pledges never to sail again.
OceanPassages has an on-board database of thousands of daily weather and position reports from hundreds of small boats on offshore voyages. OceanPassaqes can be used to plot this raw data out in a number of different ways. Firstly you can define an intended route by using the mouse pointer to set up to 4 way points (as in the magenta strip in the example below). You can also set the month for your intended voyage which in this case is a transatlantic crossing from the Canaries to St. Lucia. A sample of 55 reports are found that fall within the required month and passage area. Analysis of their reported wind strengths and direction is shown on the right side of the screen. Results for other months show fewer boats on this route and a higher proportion with unfavourable conditions.
Instead of looking at winds for a particular route, in the four chart screens below, tool bar controls have been set to display aspects of wind strengths and directions over a large ocean area. In the screen below, boats with headings in the northerly quadrant are coloured red, in the Eastern quadrant green,in the Southern yellow and in the Western blue.Other charts have coloured arrows to show variations in wind strength and direction.
Operating Notes
- If you find the tool bar buttons are inactive and ‘greyed out’, left clicking the mouse cursor on the chart area of the screen will restore them to life again
- Use the tool bar buttons to zoom the chart, to switch between Pacific and Atlantic centred displays and to step off distances on the chart.).
- Lengths of wind arrow tails are proportional to wind speeds.