franksingleton
Well-known member
Thank you.
Weather info on passage.
- Thread starter G12
- Start date
Thank you.
franksingleton
Well-known member
Glayva
This thread began with a query about “receiving weather at sea,” on passages of unspecified length and ocean, on a boat of size unstated. Not surprisingly, replies were many and varied reflecting a range of boat, experience, knowledge, depth of pocket etc.
Very obviously, a small boat has limited power and space as I know with our HR34. Equally obviously, someone with a 40+ foot boat has more opportunity to carry wind generators, solar panels and, maybe, a diesel generator to keep electronic equipment functioning. We have a wind generator and flexible, detachable solar panels.
A prudent sailor will take all sensible, possible and, to him/her, affordable steps to minimise risk when sailing. That is what good seamanship is all about. Clearly, with a modicum of luck and a large slice of good sense, you can go round the world with no external weather advice. Joshua Slocum did and many before him. However, Joshua’s luck ran out as it has done for many others before and since.
Is it sensible to tempt fate? For about £100 you can buy a good battery operated radio receiver with SSB capability. Is it really sensible to cross oceans taking no heed of weather forecasts and warnings broadcast under the GMDSS? I know full well that they will not be right all the time but to ignore them just seems like folly.
If you do have a larger boat and can generate enough power to use an Iridium phone from time to time or a low power computer running of a 12 volt supply, is it really sensible to turn your back on the best advice available? Yes, I know that, because the main data source in the Southern hemisphere is satellite based with far less in situ data, predictions are less reliable than across the Atlantic. However, that does not make it sensible to ignore GRIB files and/or synoptic charts in either ocean. Too many people use them for them to be gimmicks. Similarly, the equipment to receive them are not toys. The minimum equipment required to receive such professionally produced information need not be expensive compared to the cost of buying, running and maintaining a sea-worthy yacht.
You look at your boat and your budget. You then decide what is sensible for you. Please remember that you, personally, may not want any external help or sympathy if you come to grief. Others may have more reason to take all possible, affordable and practicable means to minimise risk. That is what the RYA and other such organisations preach. That is a philosophy to which I subscribe. For most but, clearly, not all it is the most sensible pragmatic approach to life at sea.
Athene V30
Active member
The thread is on the Jester Challenge forum - that gives a bit of a clue as to the boats most of us have!
I guess if I were better off, with a bigger boat I might have different kit, but sailing with the kit I have is safe. After all even Michael Fish got it wrong - oh yes I was at sea then too but that was watchkeeping in an aircraft carrier.
franksingleton
Well-known member
OK. I had not really taken that on board, but others did talk about kit no less sophisticated than I have been doing. Being self reliant does not mean necessarily throwing babies out with bath water,
Don't get me onto Mike Fish. First, the science has moved on greatly since then. Secondly, listen carefully to the complete quote, not just the BBC edited "highlight."
co256
Member
That's a great thread!
I used a Roberts R861 to receive Herb on 12.359 Mhz (USB) on the way back to Falmouth with a length of cheap hi-fi wire as an antenna, pulled up the mast when I needed it, nothing high tech. One evening Herb commented how surprised he was that I still had copy on him so far West, I was in the Western Approaches he is in Canada, he went on to say that people using dedicated SSB kit regularly have difficulty receiving him! I could still hear him safely tied up in Falmouth!
I like the idea of a cheap netbook hooked up to the receiver, I may well look into it further.
"Of course there is also the theory that there is little point in knowing the weather as there isn't much you can do about it, so why stress about trying to make sure that a forecast is always available."
"Stress" is an interesting point also, I didn't use any form of external weather forecasting on the way to Newport beyond the shipping forecast on 198LW and my own poor observations, I had some horrible weather but managed everything as it unfolded. Conversely, knowing what was coming on the way home did increase my stress levels! But the idea that there is nothing you can do about bad weather isn't entirely true, thanks to Herb I managed to get myself away from the worst of it and on some occasions in downwind conditions rather than headwinds.
At the end of the day you'll take what you want from all of this, you'll pick through the chaff until you find your own personal wheat, then the real learning begins founded on your own personal experience and there's nothing comes close to that.
Good luck.
frauboot
New member
So your original statement that we had obligations to carry certain equipment under SOLAS regulations was intended to mislead? Or at least those of us interested in sailing small boats across big oceans.
franksingleton
Well-known member
I have never said that we, leisure sailors had to carry NAVTEX or, indeed, any other equipment The requirements placed upon us under SOLAS are set out at http://weather.mailasail.com/Franks-Weather/Solas-Gmdss-And-Leisure-Sailors#leisure. For instance, when you go to sea you are legally required to have a passage plan and to have checked on weather forecasts.
I did say that SOLAS convention vessels are required to carry NAVTEX. That is commercial vessels > 300 grt and certain others eg training yachts.
Conachair
Guest
Much fun and very educational
. Gribs I'm not a fan of, too localised unless you can afford the satphone airtime. But weatherfax I've found accurate around the atlantic, though like any forecast they drift out quickly. Usefulness may well be different for different passages, crossing towards Azores around 38N the weatherfax synoptics were very useful showing the path of the lows, going up or down a bit could make a big difference in wind speed. UK / Azores the weather patterns are different, though further south I'd would want some form of synoptics to see where the azores high was sitting, could make the difference between becalmed and sailing slowly.
I can see the attraction of sailing completely self contained, offshore must be the only place where any of us can really switch off the modern world, much more practical than a month in a cave in the Himalyas
But personally I much prefer to have ssb reciever and weatherfax onboard. Radio only costs about 35 quid and assuming there's a laptop or notebook onboard it's about 20 minutes a day or two power. And I get bored, it add's a focus to the day, midday distance run and a look at the weather.
Each to their own though, 'tis your boat and your ocean.
Dharma Bum
New member
Navtex and SSB receiver for sale
I'm selling my boat's Navtex Pro and SSB receiver if anyone's interested? Check out the 'for sale' thread. You know, these might have saved Joshua Slocum's life!
I'm selling my boat's Navtex Pro and SSB receiver if anyone's interested? Check out the 'for sale' thread. You know, these might have saved Joshua Slocum's life!
lenseman
Active member
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G12
Member
I've sat back and watched this thread from a distance, there's some really good stuff turning up. I still don't know what I will decide to do yet - I need the backstay shortened in order to install a new slightly longer tensioner, I might get a new one made with the insulators for HF - possibly a waste of money, but useful to have if I suddenly decide to go for it.
I would also like to learn more about the weather and how to interpret the forecast. No good having the data if you don't make best use of it.
I would also like to learn more about the weather and how to interpret the forecast. No good having the data if you don't make best use of it.
fisherZ
New member
Plenty of info on Frank's site.
G12
Member
Indeed! I've just visited it.....
Conachair
Guest
Simon Keeling posts on these forums sometimes and his videos are great - http://www.weatherweb.net/wxwebtv2.php
franksingleton
Well-known member
Interpretation depends upon what you are trying to interpret.
For various reasons including available time and comprehension, broadcast worded forecasts such as high seas, shipping or even inshore forecasts have necessarily to be general and broad brush. The larger the area, the broader the brush. To my mind, they have two uses. First, as the term GMDSS implies, they are warning services. Secondly, the give an experienced human interpretation of what the numerical weather prediction programs are saying.
Synoptic charts, such as those produced by the UK Met Office and DWD available on Radiofax, again give an interpretation of computer model output. If you can get GRIBs, these are an excellent tool for looking ahead up to about 6 or even 7 days in general terms. If you can get worded texts, synoptic charts and GRIBs then you get the best advice possible. Note the order of the last two words.
Given at least two of these, then any sailor is virtually self reliant. There should be no need to be using shore based assistance whether it be Herb or your wife sending copies of forecasts. Given modern communications, whether by HF radio, Iridium or INMARSAT-C (the latter not feasible or affordable for most), there should be no reason for any yachtsman to be devoid of forecast advice.
For most blue water sailors, ie those not in mega fast yachts, the best use of forecasts is as warnings of adverse weather to come. Routeing, other than climatologically, is very hit and miss on long passages. A friend of mine claims that he recently beat the AZAB fleet home giving them a day start. Such use must be fairly rare. Coastal hoppers can best use forecasts to ensure that they do not go to sea in bad weather and they can ensure that they are in harbour or a safe anchorage before bad or adverse weather arrives. My well worn phrase is to “Avoid being in a port that you do not want to be in, in weather that you do not want to go out in.”
The longer ahead you can see with reasonable confidence, the better. Using forecasts for our extended 5 month summer cruises, I have seen the reliability of GRIBs improve over the past 10 years. It is now rare to get seriously misleading forecasts as far as 6 days ahead. I am not saying that they will be accurate (difficult to define) but that they will be unlikely to lead you into trouble. Usefulness and accuracy and not synonymous.
G12
Member
I saw him speak at last years London boat show, he certainly knows his onions. I like his forecasts too, there's more info in them than I know how to use though. I think he does courses but I'm not sure. I'd definitely consider going on one if time allows.
Frank, thanks for the extra info. I too like GRIBs, I have them on my iPhone and use them very regularly for marine and non marine applications. They would be a real bonus at sea and the downloads aren't enormous either. I'm usually somewhere I can get a phone signal at least every few days so it's not bothered me yet, but it will do on the JC.
Conachair
Guest
This one might be of interest.
http://www.anymeeting.com/WebConference/RecordingDefault.aspx?c_psrid=E959D8808449
500mB charts are something I'm slowing getting the head around now, they seem to be vital for any kind of longer range hints about which way it's going to develop.
franksingleton
Well-known member
It may seem like heresy for a meteorologist, but I do have to query whether there is any real practical value in studying upper air charts. Using 500 hPa (mb) charts is really a technique of the past. Before and in the early days of numerical weather prediction, we used them to identify areas where lows would develop or highs build etc. It was all very subjective and very much in a by and large manner. Our results were far inferior to the output from NWP models.
NWP models use vast amounts of data from the surface of the earth right up to about 80 kms. In effect, they do the sums that we can only guess at. Any forecast charts at 500 hPa or other levels will have been produced by the NWP programs which model the entire atmosphere as a whole. In other words, surface weather forecasts produced by the computer and which we can see as GRIBs will be consistent with the upper air charts.
If you compare output from NWP models you will find little difference between them up to 3 or 4 days ahead. After that the more sophisticated models with better analyses come out best. Even then the differences are not generally large. For example the ECMWF 84 hour forecast is probably as good as the GFS 72 hour. Partly, the model is a little better. Partly it is because they can afford to delay running their forecast as they do not have immediate operational commitments. That means that their analysis is better than the operational centres.
I doubt that anyone can significantly improvement on the NWP output in general; large scale patterns. There is always scope to add value in local detail, especially over the first 24 to 36 hours or so. Upper air charts are insufficiently detailed to give much help for that purpose. To get that local detailed improvement you have two real choices. First, use a service such as that offered by Simon Keeling; secondly, rely upon your own experience, nous and commonsense.
G12
Member
Frank,
I notice that you're on the list to do a Forecasting at Sea course at the CA at the end of the month. I *may* be able to attend but it'd be last minute owing to the unusual way I work at the moment. Any idea if there's any room left? I noticed it's for a max of 25.
G.
I notice that you're on the list to do a Forecasting at Sea course at the CA at the end of the month. I *may* be able to attend but it'd be last minute owing to the unusual way I work at the moment. Any idea if there's any room left? I noticed it's for a max of 25.
G.
franksingleton
Well-known member
I am not the organizer so do not know how bookings are going. I can only suggest that you telephone CA House and ask. Of course, if you are a CA member, you might like to contact Peter Flower direct.
I am giving 4 talks.
1. Back to Basics in which I give better explanations than you see in standard Yachtie textbooks of Coriolis, how pressure gradients form, how sea breezes occur. I have long thought that if you understand the basics, then the rest should follow.
2. The General Circulation. How the atmosphere works on the large scale. Trade winds, Easterly waves and hurricanes. Jet streams and extra-tropical depressions.
3. Numerical weather prediction. GRIB files, what they are, what they can and cannot do. Getting and using them with other tools.
4. Fronts and local effects – essentially, how the user can add detail to forecasts.
I did something very similar last year – billed as an Advanced Weather course. The idea being to go well beyond the Yachtmaster syllabus. This time, I am saying less about NWP but more on its use via GRIBs,
It is intended to be a fairly stretching type of day, not least for me, and numbers are being kept fairly small so as to encourage discussion after each talk. I am sure that there will be some flexibility regarding numbers.