Sailing to the British Virgin Islands in the Caribbean 1500
How We Got Our Weather Information
| ||Fair winds and seas in the morning.
We had numerous ways to receive various types of weather information:
- Initial briefing - Before we left, the Caribbean 1500 organizers provided a weather and Gulf Stream briefing at one of the meetings at Bluewater Marina. This is one meeting that we went to, and we all took detailed notes.
- Private weather forecaster - Every morning during the trip, Caribbean 1500 participants received a comprehensive weather forecast via SSB radio from Chris Parker, a private weather forecaster. The forecast included the location of fronts, highs, and lows, wind speed and direction, and sea state. The coverage area was broad enough to benefit the whole fleet, even after we became spread out towards the end of the trip. He also made himself available after the forecast for brief questions via SSB radio. If distant boaters couldn't hear Chris, other boaters would relay the forecast information. If requested, he could also email a forecast via PACTOR radio email. Chris' forecasts tended to be very useful and quite accurate. Although his services had been arranged by the Caribbean 1500 organizers, he also provides forecasts to individual boaters on a subscription basis (see the internet link below).
- Roll-call winds - Every morning and evening during the trip, all the boats checked in via SSB radio with a Caribbean 1500 organizer. Among other things, each boat provided its location plus the wind speed and direction. We always listened to this information and sometimes we wrote it down. You could get the most value from this information if you plotted all the wind information on a chart, but trying to do this manually would be way too time consuming.
- Weatherfax - The National Weather Service has several long-range radio transmitters around the country that broadcast information to mariners in "fax" format. They follow a published schedule, transmitting numerous faxes throughout the day containing all kinds of useful information. We were most interested in receiving a few particular maps/charts: Surface Analysis (which shows the current weather), 24- and 48-hour Surface Forecasts (which predict the weather for tomorrow and the next day), Sea State Analysis (which shows the current significant wave height and swell direction), Wind/Wave Analysis (which shows the current significant wave height and wind speed/direction), and the 24- and 48-hour Wind/Wave Forecasts (predictions for tomorrow and the next day). I found the weather fax information to be very useful, although you have to be able to understand and interpret the charts.
We were able to receive two stations, NMF from Boston or NMG from New Orleans. We usually got better reception from the Boston station, but the Boston weatherfaxes covered an area farther north that didn't include the full Caribbean. On the other hand, the New Orleans weatherfaxes covered the entire Caribbean but it was harder to receive good clean copy from the station.
We had two ways to receive weatherfaxes on the boat. The main way was using the Furuno weatherfax that was part of the Navnet system. Using a set of menus, you could program the weatherfax to receive any standard weatherfax frequency. You could also program it to turn on and off at certain times during the day if you didn't want to receive all the faxes from a particular station. I thought this feature was hard to use and it worked poorly, so eventually I reconfigured the system to receive all faxes even though they weren't all of interest (like the ice reports for Greenland). After the system received a fax, it would store the information in an internal memory that could hold up to 12 faxes, depending on their size. Then you would use the Navnet chartplotter screen to view the fax, or to erase it or reconfigure the weatherfax operation. You could also view the weatherfax on a PC attached to the Navnet network, which would allow you to save the fax to disk or print it out (although we never did that).
The other way we could receive weatherfaxes was using the SSB radio, the PACTOR modem, and the Airmail program running on the PC that controlled everything. The Airmail program had a separate module that could receive weatherfaxes, and although I got it to work before we left, we never used it during the voyage.
- GRIB files - These are small binary files that contain weather forecast information for a particular area and time period that you specify. To make it work, you need to be able to send and receive email from the boat. You first send an email to a weather server requesting forecast information for a particular area and time period. After waiting a few minutes, you check your received email and hopefully can download the GRIB file containing the requested information. It's also possible to configure the weather server to periodically send GRIB files without having to request each file via email. The danger with this method is that it can clog up your mailbox with files if you run into problems trying to receive the GRIB files. Once you receive a GRIB file on the boat, you have to use a GRIB file viewing program on a computer to interpret the data and display the forecast information.
Jeff requested GRIB files in two ways: At the beginning of the trip, we were still within cellphone range, so he was able to send/receive GRIB emails using a special data-only cellphone that plugged into his laptop. Also, a couple of times during the trip, he was able to send/receive GRIB emails using his rented satphone, although the airtime charges were very expensive. There was a potential third way to send/receive GRIB emails, using the PACTOR modem and the SSB radio. Before we left, I got the PACTOR modem to work over the SSB radio and was able to send/receive emails, but we never used the PACTOR system during the voyage.
After receiving a GRIB file, Jeff would use the MaxSea navigation software to view the forecast information. The program was able to graphically overlay the forecast information on a chart of our current position and planned route.
- Radar - We could monitor our local weather using the boat's Furuno radar. The radar was particularly good at detecting squalls, which were easily visible on the screen as big red blobs that would slowly move. We would sometimes use the radar at night when it was hard to see what was going on. The radar could easily tell the difference between an ordinary cloud (barely detected, if at all) and a cloud with active weather (big red blob). To conserve power, we didn't operate the radar continuously; it was easy enough to turn it on for a few minutes periodically to see how things were progressing.
- Wind instruments - Night Heron had a wind speed/direction sensor at the masthead with an electronic readout at the helm that indicated the "relative" (rather than "true") wind speed and direction. This device was useful at night when it was difficult to see the usual evidence of wind speed/direction (like the sea state, the set of the sails, etc.). It was especially useful during nighttime squalls when we would have to steer the boat to the wind to avoid overstressing the sails. At these times, you would be standing in the pitch-black cockpit with the rain-spattered plastic side curtains deployed all around, and you'd basically be sailing on instruments with no visual reference to the outside world. This technique required some practice to develop competency.
- Shortwave radio receiver - Although we never used this method, various stations broadcast weather forecasts using a synthesized voice, allowing you to listen to a forecast using an ordinary shortwave radio. This is a very simple technique that uses the least amount of technology, and it was available to us as a backup if we needed it (the ICOM SSB can operate as a shortwave radio receiver).