24 June 2018

The Cost of Professional Weather Forecasts

Somewhere in the last 6000 nm, it occurred to me that I needed to learn more about marine weather. My path of learning had followed the usual pattern:
  1. Obliviousness -- I didn't know what I didn't know
  2. Absolute Surety -- I knew just enough to think I knew everything
  3. Utter Self-doubt -- I knew enough to know that I knew nothing
  4. Novice Level Awareness -- I know enough to be cautiously confident in my abilities
Having finally reached Novice Level, I want to write down what I'm doing, mainly for my own reference, but also to help others who might be further down the learning curve. I provide links to resources it took me a long time to track down, and which I would like to finally have in one place!

This first in a series of weather-related posts will focus on the cost of getting essential marine forecasts while offshore -- i.e. when the cell phone towers disappear over the horizon.

When you are beyond easy reach of the Internet, you must either:
  • Learn to make your own forecasts using the instruments available to you on your boat (eyes, skin, wind instruments, barometer, etc.)
  • Figure out a way to access professional forecasts. 
For hundreds of years, ship masters had to make their own forecasts, but the National Weather Service (NWS) with it's fleet of buoys, ships, weather satellites, and supercomputers do a much better job. Watching the sea, sky, and barometer still makes sense, but getting professional forecasts whenever you can is simple prudence.

Beyond the range of easy Internet access, you have several options for receiving professional forecasts, but the most common (and the only one's I have experimented with) are:
  • SSB Radio (which Petronella came with)
  • Satellite Radio
With an SSB radio you can:
  • Receive Offshore and Highseas weather forecasts by voice, by tuning in to the forecasts broadcast by the US Coast Guard several times a day. (Details and schedule.)
  • Listen in on weather nets, such as those hosted by Chris Parker. (Details and schedule)
By adding a SSB modem such as a Pactor, a laptop, and an email service like SailMail, you can also:
With a satellite radio, such as the Iridium Go, you can receive the same professional forecasts by email. Forecasts sent by voice over HF radio are, of course, not available, but it is much easier to receive the same text by email, anyway. (I'd rather go to the dentist than listen to the Offshore forecast on SSB.)

Thus, the benefits of SSB and Satellite are the similar: professional forecasts received in a timely manner. However, the costs are different:

Monetary Costs

The cost of an SSB transceiver, antenna, antenna tuner, and modem will set you back at least $4,000 USD, not including installation, which could be expensive. Once you purchase the equipment installed, receiving forecasts is free, apart from a subscription to an email service like SailMail.

The cost of a satellite system such as the Iridium Go is under $1,000, and installation is trivial, but you also need to purchase airtime and an iPad, if you don't have one. Depending on how much you use it, it might well cost you $4,000 over a period of years.

Energy Costs

When I started experimenting with Petronella's SSB/Pactor/SailMail system, I quickly discovered a hidden cost of SSB Radio -- amp-hours! Our ICOM SSB is relatively efficient when you are just listening, but as soon as you start doing more, the batteries start groaning.

Sending and Receiving email involves transmitting and receiving data, and also requires the use of a laptop, which has its own power demands.

Downloading a set of weather charts using RadioFax takes over an hour. You can use an iPad instead of a laptop to decode the faxes, and thus save amp-hours, but it is still taxing on the ship's batteries.

My point is that you have to factor in the cost of generating all those amp-hours, unless your boat already generates loads of excess energy. Petronella just couldn't keep up, even with four new heavy-duty golf-cart batteries, and a relatively robust set of solar panels.

The energy cost of running a satellite phone and an iPad are much less. Almost negligible, in fact.

Physical Costs

On an offshore passage, I've learned that it is critical to manage not only amp-hours, but human-energy-hours. After the first day or two, it is easy to get tired, and hard to get rested. Energy wasted listening to scratchy SSB voice broadcasts, or struggling to download email over an iffy SSB connection, or monitoring the download of RadioFaxes is time better spent sleeping. And if you happen to be dealing with nasty weather when the SSB schedule says you should be listening or downloading, well, you are just out of luck.

The physical cost of obtaining a forecast via satellite phone and iPad is much less. You can easily do it while lying in your bunk -- exactly where I like to do my weather forecasting.

Bottom Line

After getting Petronella's SSB system working and experimenting with it on several passages, I came to the conclusion that the total cost of receiving forecasts by SSB was too expensive for us, and I purchased an Iridium Go. We recently completed a six-day offshore passage from St. Augustine, FL to the Chesapeake Bay, and I can confirm that it was much cheaper, energy-wise, to get essential weather information using the Iridium than it ever was using SSB.

I am still glad that we have the SSB, since it is essential for participating in cruising nets and for long-range distress calls. However, for getting weather forecasts, we now consider the SSB as our backup system.

Next Up: Another Look At Weather Faxes


  1. (a) David Burch:: I think one of the most import authors on marine/nautical topics. His book ' Modern Marine Weather" is in it's third edition. Also check his blog and YouTube. (b) Website 'Windy' The weather animation is based on the open sources project of Cameron Beccario earth dot null school. Meteorologists love it and recommend it for its ability to help one visualize the atmosphere. Not an offshore tool but a must see before leaving port.


    1. David’s books are great. I don’t know how he gets so much done! The Windy app is tops when onshore. Offshore I use PocketGrib for two reasons:you can import GRIB data received by email into it, and it graphs the data, which I find is easier/faster to interpret than the usual map presentation. Check it out!


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