Weather and communications on the passage

PW screenshot

If you’re following along, you know we left Ascension Island a few day ago. Now, most of passages over time seem to top out around five days. We’ve had a few longer ones (especially in the Indian Ocean), but that’s pretty typical at the high end, and mostly they range closer to about three days.

This passage, from Ascension to Barbados, will take around three weeks. It’s about 3,000 nautical miles: slightly longer than our longest passage to date, from Puerto Vallarta, Mexico to Hiva Oa, French Polynesia, six years ago this month (time flies!).

Food: check. Books: check. Movies/podcasts: check. Weather: a little more involved than just scaling up! Why that duration matters in terms of weather in particular is that forecasts generally aren’t all that reliable after a few days out. With longer passages like this- well, there’s a reason they’re called weather “forecasts” and not “predictions” – because circumstances change! When you’re on a long stretch like this, of course, it’s pretty much guaranteed.


I really have no interest in tempting fate by being out of tune with weather. “Misery is optional” (or as my friend Lorraine would say “no pain, no pain”!)  — why be uncomfortable if you can avoid it? Why take unnecessary risks? So we stay fastidiously in tune with the weather. Historically we’ve relied a lot on our HF radio for at-sea comms, from basic email and for weather info. But for more than a year now– since January 2014– we’ve relied increasingly on an Iridium GO. And as we left the African continent, we switched to rely almost completely on the Iridium and PredictWind (that’s PW’s Offshore app screenshot on an iPad at the top of this post). The latter switch has been partly by circumstance, because our Pactor modem packed it in and no longer allows us to send/receive mail via HF – the primary method we used the HF for weather.

You know what? We don’t miss it.

We’re getting everything via the GO instead. The last two passages– to St Helena, and then to Ascension–were downwind rhumb line passages where the main weather watch was just to be aware of bigger trends. Along the way, Offshore is fast and easy to incrementally updated weather information and routing recommendations–this app, on our iPad, is now the weather source we rely upon by far the most for passagemaking.

It’s going to be an interesting one, that takes more thinking than the “point and go” dead downwind runs in recent memory. See that big band of purply-blue in the top picture? That’s the ITCZ, where there’s pretty much NO wind. It moves and wiggles and meanders, and we want to get across it at the narrowest possible point. Traditionally, cruisers pick a waypoint to aim for based on historical information. but that could mean going through something like six degrees of latitude in the ITCZ, where you either have no wind (HOT, motoring, ick) or too much wind (squall city!). While we have a point in mind for crossing this zone, which will almost certainly be a dive to the north with the engine on, watching the trends will help us keep that motoring time to a minimum, and have a more comfortable and faster passage.

We’ll also use the GO for tasks previously relegated to the HF, like getting ocean current data via Saildocs (there’s a lot of current at play to make smart routing decisions between Ascension and Barbados). The routing function, which is especially helpful on passages like the one we’re embarked on, where the most efficient path is actually serpentine thanks to a mix of the equator / doldrums, ITCZ, and different currents and tradewinds.

We do still use the SSB for nets, and enjoy touching base with other cruisers. There’a a twice-daily informal net where we do a roll call for participating boats in the vicinity…”vicinity” being a thousand mile or so stretch, but who’s counting?! And it’s nice to have a live chat with friends off net times, too, where we can relay messages for a singlehander (who doesn’t have the ability to post his position) with his his loved ones at home.

While the nets are a welcome part of our day, there less useful for weather, except to see what the real-time conditions are for boats around us and think about how that differs from the forecast in terms of any weather shifts we should anticipate. But generally, the weather data is just repeating info we can get for ourselves, and in much more detail, via PW Offshore. In the South Atlantic, South Africa’s land-based SAMM net has been a great resource providing weather to cruisers on their roll call. Their biggest value to us, and a reason I hope ever to be without HF radio RX/TX, is support in the event of an emergency.

A bigger view of our passage ahead, showing start/end points. We’ve got a long way to go!

bigger view

Totem is at sea! We’re headed for Barbados; you can see our current position and speed here. We will get comments while we’re underway, so add yours and consider it a welcome distraction to our day out in the South Atlantic. We’ll be able to respond after we reach the Caribbean and find real interwebs again.

20 Responses

  1. I’ve been keeping an eye on y’all on the website. Good thesis distraction. 🙂

    If/when you have a moment/connection to explain to a landlubber though why you’re aiming to still cross some of the blue part, instead of scooting over to the green where there’s still *some* wind, I would appreciate it!

    1. No real theme… they were all across the board! Well, the girls watched a lot of anime in their off time. Niall likes military history movies. I didn’t watch any, but read about a book a day!

  2. Hi there! I’ve just found your blog.. and wow.. it’s so nice! Good to read and learn about situations which are so far from my coastal, minimal, sailing and land-life.
    I’ve linked yours to my blog here (if you don’t mind!), so I can follow you more easily.
    Fair winds!

  3. Hola Totem crew!! Thinking of you out there in the big blue as I’ve been here in snowy MA this week (yup it snowed about 6 in. In western MA)! Hope the passage is smooth!

  4. Looks like you’re still in the green yellowish zone, pity you dropped to 5 knots, but still going which is great ! The blue line on my screen is still getting longer eacht morning I check on you guys ! It’s the first thing I do every day ;-)…. going great, keep it up and what else is there than just to keep going 😉

  5. Hi Behan,
    I’ve subscribed and get your posts in my inbox now. This one was fascinating, about your weather-watching and long passage prep. I’ve enjoyed them all….your reports from both St Helena and Ascension and your funny ones about menus. Hey it’s the daily stuff that matters. I would like to invite you to follow my blog…I have been posting about our travels for a month in Namibia last summer…as well as writing about my parallel painting project, called Namibian Portfolio.
    Safe travels, and I do believe we are destined to cross paths in Seattle!

  6. Hi Behan,

    Love reading your posts – informative and still inspirational, thank you.

    Question about Iridium Go: how are you finding the coverage and speeds? I notice you still read Facebook on passages and that’s usually very data intensive. And have you done many phone calls? Is the quality of the call decent?

    Thanks in advance!

    1. Hi Katia- when we started using the GO, the speeds were slow, and frequently disconnected (timing out) before transmissions were completed (at least they picked up where they left off at reconnection, instead of starting over!). Those disconnects are rare now and the speeds are significantly faster. It’s still *slow,* mind you, compared to anything normal. When I access Facebook via the GO, I am using a text-only browser that makes for the smallest data sip I can manage. And I always have a book with me, because i can read several pages while the next FB page loads. 🙂 We’ve made some phone calls and the sound quality is good, but there’s a meaningful delay which some folks find difficult.

      1. Behan,
        Good to know speeds are faster now because I’ve been doing a lot of research, trying to decide whether to invest in a GO! before our next ocean crossing this winter, and so many users in the past have complained about how slow the speeds are…and the disconnects.
        How long does it take to download PredictWind weather data? Are you able to run departure or weather planning (if you subscribe to that). Even when I’m running them on normal wifi speed, it takes a while for them to process. Is it possible to run them on the GO!?
        I didn’t realize you could use the GO! to access saildocs for ocean currents. You are finding it useful to do that from another app in addition to getting data from PredictWind? We could’ve used that when we crossed the gulf stream in 2014!
        Looking forward to more feedback from you on how well the Iridium Go! is working.
        Lastly, if you don’t mind my asking, are you a sponsored user, i.e. received any discount or other consideration from Iridium? – I’ve heard they’ve been giving some cruisers some $ in exchange for reviews.
        Thanks in advance, Ellen

        1. Hi Ellen, the time it takes to download PW weather data depends on how much data your asking for and how well the satellite connection is working. We tune it to be about 140k while underway, and the download rate is about 15k/minute, so that’s 9ish minutes. But that’s for a big passage; as you progress and request smaller areas, the data you need is also smaller, so it might only be a minute or so to get what you need. We’ve played around with the planning but tend to work mainly with gribs and routing and routinely request updated routing while underway, to see any adjustment in response to changing conditions. Re: ocean currents data, the nice thing about seeing it standalone is you can better understand what’s baked into a recommendation blending ocean currents with other source data. For clarity, we do not have any financial incentive or discount or whatever you want to call it from Iridium and paid full retail for the GO.

  7. I appreciate these helpful posts so much! As a newbie trying to figure everything out, you speak a language I can understand. I am trying to figure out if I need to upgrade to the PW pro to access the current info for our Bahamas trip. Do you think that is necessary or will our standard account be sufficient info. I realize everyone’s comfort level of info is different but I know you guys have cruised the area. Thanks again!

    1. Hi Nikki – Standard subscription is very good, minus a few excellent pro features that probably aren’t necessary for Bahamas. If you start jumping to other islands groups then perhaps. If you have SSB then you can incorporate Chris Parker’s forecasts. I like multiple sources of data, and there is plenty out there such as different current models, or reports of convection (which doesn’t really show in GRIB models). Email me if you more questions

    2. Hi Nikki, I was just looking at Jamie’s answer to your question about ocean current info for jumping out to the Bahamas and thought I’d add a little more. First, we haven’t been to the Bahamas (looking forward to it – SOON!). To be super clear about what’s in/out with PredictWind, you don’t get ocean current info baked into routing at the standard level: that’s just in the pro level. Do you need that ocean info to cruise the Bahamas? I don’t think so. But I believe you have ocean transits ahead and for bigger routing, or places with more complicated current factors over distance, that will be really useful. If that makes you consider holding off, but you’re niggled by wanting some data on current, there *are* other places to get data on ocean currents, over the Iridium, while you’re at sea (and even better options when you have a good internet connection). I’ve written about that in this post.

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