Sailing to the British Virgin Islands in the Caribbean 1500

Navigation (continued)

Click the image to launch Google Earth and display a track map of our voyage. If Google Earth doesn't automatically open, right-click the image and download the .kmz file to your computer, then run Google Earth manually and open the downloaded file. If you don't have Google Earth on your computer, there's an internet link at the bottom of this page to download a copy.		Click the image to launch Google Maps in your browser window and display the track map. This option is available for people who don't have Google Earth installed, however Google Maps is much slower than Google Earth when displaying lengthy tracks.

During the voyage, the Caribbean 1500 organizers maintained a real-time track map on their web site, updated every four hours, that showed the current position of every boat. In addition, the track map showed the real-time weather conditions and sea state as overlays on the track map. This was an impressive technical feat, made possible by an equally impressive piece of equipment that the organizers had loaned to each skipper. Before the event started, the organizers handed out a small satellite transmitter to each skipper, with instructions to install it someplace on the boat with a view of the sky. The device was about the size of a small laptop computer, and Jeff installed ours under the dodger using the provided velcro adhesive strips (they said it could transmit through dodger canvas). The device had an internal GPS and satellite transmitter, and was powered by an internal battery that could last up to several years. There was no external antenna, no power connection, there were no connections or user controls whatsoever—not even an on/off switch—just stick it down on a flat surface with a view of the sky, and you're done. Needless to say, since there was no way to interact with it, we pretty much forgot about it, other than remembering not to put anything on top of it.

The device worked well and the real-time track map was a real plus. Not only did it keep interested parties informed as to our boat's location, but it would have been very useful in locating the boat in case of emergency. The satellite transmitter was extra-useful for Night Heron. All the boats in the fleet regularly reported their positions via SSB radio, but our radio put out a very weak signal that was rarely received. Due to the damage to our sails, we were traveling relatively slowly and took much longer than typical to complete the voyage. Since people couldn't really hear our SSB position reports, the organizers relied on our satellite transmitter to keep track of our slow but steady progress towards Tortola.

Unfortunately, I haven't found an archived version of the Caribbean 1500 track map on the internet, so there's no way to see what it looked like. I do have a few internet links below for more information.

Here's a summary of our voyage, with statistics for each day. The time is Atlantic Standard Time, mileage is in nautical miles, and speed is in knots.

15 days, 3 hours elapsed time
1518 miles overall, 100 miles/day average
1299 miles made-good, 86 miles/day average

The overall mileage figures were easily obtained from a GPS, but the made-good figures required a little work. Here's how I figured them:

Before you can figure out any daily made-good figures, you need to know the total distance from your initial starting point to your final destination. In our case, the initial starting point was Tidewater Marina in Portsmouth and the final destination was Village Cay Marina in Tortola. Obviously, there are an infinite number of possible routes between those two points, but we want to know the length of the shortest practical route.

Before we left Portsmouth, I computed this distance using paper charts and my GPS. Using Chesapeake Bay charts, I laid out the shortest practical route from Tidewater Marina to buoy "CB", which is in the ocean outside the mouth of Chesapeake Bay. Then by walking a pair of dividers, I measured this distance and wrote down the number (40.1 nm). Using Virgin Island charts, I plotted a safe arrival waypoint west of Anegada, then laid out the shortest practical route to Village Cay Marina (32.8 nm). Then I used my GPS to measure the great-circle distance between buoy CB and the BVI arrival waypoint (1226.3 nm). I did this by entering lat/long waypoints for buoy CB and BVI arrival, then selecting the CB waypoint as a position offset (from my present position, which was irrelevant) and seeing how far the BVI arrival waypoint was from CB.

The total of those three distances is the shortest practical distance (40.1 + 1226.3 + 32.8) = 1299 nm, which became our initial "distance to go" in the passage summary table. Thereafter, every day at about 08:45 am, I turned on my GPS and determined how far we were from the BVI arrival waypoint. To this value I would add 32.8, which is the distance to be traveled in the Virgin Islands, and the sum would be the new "distance to go" for that day. After entering the new value in the passage summary table, I would subtract today's "distance to go" from yesterday's "distance to go", and the difference would be the "miles made good" over the previous 24 hours.

Click on the picture to launch Google Earth, which will then display waypoints for a route through the islands to reach Village Cay Marina on Tortola. These waypoints were part of our backup navigation, and were plotted on paper charts and manually entered into a handheld GPS. We didn't sail this exact route, but instead sailed a very similar route that was plotted on MaxSea and uploaded to the Furuno chartplotters. If Google Earth doesn't automatically open, right-click the image and download the .kmz file to your computer, then run Google Earth manually and open the downloaded file. If you don't have Google Earth, click here to display the route and waypoints using Google Maps (use your browser's "back" command to return here).

In the next section, I'll present some details about the communications equipment and procedures for the Caribbean 1500.

Links To Pages On My Web Site

• How To Make A Track Map For Google Earth - At the top of the current page, you can click on a picture to launch Google Earth and display a track map of our voyage. I wrote up detailed instructions on how to make such a track map, and you can read about it by following this link.
• Sample Logbook Sheet - I made up a blank logbook sheet (which we never used) to keep track of hourly lat/long, course, speed, weather, seas, etc., with 24 entries for a full day. The logbook sheets are designed to be kept on a clipboard, which in turn would be stored in a water-resistant plastic pouch in the cockpit. If you want, you can download the logbook sheet as a Word file or download the logbook sheet as an OpenOffice file. For either file format, right-click the link and select "Save Target As...", then enter a file name and download the file to your hard disk. If the download process wants to change the OpenOffice file extension to .zip, change it back to .odt.
• Passage Summary Sheet - I have a blank sheet similar to the above passage summary table; you can download it as a Word file or download it as an OpenOffice file. For either file format, right-click the link and select "Save Target As...", then enter a file name and download the file to your hard disk. If the download process wants to change the OpenOffice file extension to .zip, change it back to .odt.

Internet Links For This Section

• Cruising World - short article about Caribbean 1500 satellite tracking
• Axonn AXTracker T3 - the satellite tracking transmitter used on every boat
• Globalstar - the satellite network used by the Axonn transmitter
• Magnalox - the software used to plot boat positions
• Google Earth - all about Google Earth, plus a link to download the application