PredictWind? Weatherfax? What weather system do you recommend for crossing oceans?

[Auspicious]

Originally Posted by Exile

I would have no problem anchoring the night before in one of your suggested locales, and could certainly offer nicer sleeping accommodations than the floor!

Just give me as much heads up as possible when your plans start to firm up.

Originally Posted by RobPatterson

SSB with Pactor modem, subscription to Sailmail makes getting GRIBS easy. Also makes getting info from pro weather routers easy.

If you have a Pactor modem you have built-in one of the finest weather fax demodulators available.

Originally Posted by StoneCrab

Pactor modems are mentioned a lot.

I have some questions about these modems, but primarily, I am wondering if they are still required. Wouldn't a computer be able to handle all the data translation if it is wired to the SSB?

As someone noted there are software options. Rick Meuthing of the Winlink Development Team has done some outstanding work, standing on the shoulders of SK Vic Poor. The issues are that the sound cards and processors in a computer are not as repeatable and stable as the hardware DSP in a Pactor modem. WINMOR and ARDOP are a lot slower than Pactor IV (although faster than Iridium which is worth thinking about). There is no commercial service that supports soundcard modes so you must have a ham license (US General or higher or equivalent from your country).

Originally Posted by Pete7

Folks in light of the information that Bill has passed away, we have changed his membership to Eternal Member in memory of the 13 years he was a member of CF and a regular contributor to all things radio.

Sadly we lost another good guy.

Bill, rest in peace.

https://www.cruisersforum.com/forums...fors-2865.html

Thank you. Bill passed in his sleep last Spring. There was no long illness and no pain.

Originally Posted by Discovery 15797

There is some weird stuff with the Iridium package. You can setup up to 5 users, but every user can see all the text messages sent and received by other users. So, I don't really understand why you need to setup different users with different passwords other than email.

There are lots of weird things with the GO!. Shared text messages are just one. In fairness, the point of setting up users is managing privileges.



Losing the Facebook interface (Facebook's fault, not Iridium) is a major inconvenience for a lot of folks.


Most of the apps and applets are clunky. Community college software developers. *grin* Not at the top of their class.

Originally Posted by Discovery 15797

Personally, I found the information downloaded on Iridium much more informative than the synoptic charts downloaded via SSB.

With respect you didn't learn to use them. How many cruisers dig into subjects like diesel maintenance, refrigeration repair, and no end of other topics but can't be bothered to learn about weather?

Originally Posted by Discovery 15797

Also, consider that you are only making about 120 - 140 nm per day. Looking at weather 5 days out is crazy

Slow boats make looking as far out as is reasonably reliable more important. You need more time to position your boat for the best weather available. That may mean tacking today rather than next Thursday in order to get the breeze you want (fuel conservation) or avoid unstable atmosphere (too much wind, rain).

Originally Posted by Exile

Interesting recording of a tornado! There are also some phone apps that perform as barographs, i.e. displaying historical readings. Assuming your device has a built-in barometer that is. The only catch (from what I've observed) is that the app must remain open on your device. I simply note readings from my old school barometer on the bulkhead every time I make a log entry.

The app I use not only needs to be open but active. It's just part of my routine to check the pressure at each meal so I keep the barograph function relevant.

[Paul L]

Originally Posted by Auspicious

.....

Synoptic charts over weather fax are a gift to cruisers. I simply don't understand why people use gribs when such better information is available.

.....

The forecasters who create the synoptic charts start with the Grib model. Gribs go out many more days. Sure you can say they are not accurate out 7 days, but that doesn't change the fact that I need info out 7 days to plan a landfall, fully understanding that the Gribs will improve significantly as the target date decreases on passage.

As the Gribs are generally, in most areas, very good for 3 days or so, what am I going to get out of the synoptic chart that will change my passage plans?

[Auspicious]

Originally Posted by Paul L

The forecasters who create the synoptic charts start with the Grib model. Gribs go out many more days. Sure you can say they are not accurate out 7 days, but that doesn't change the fact that I need info out 7 days to plan a landfall, fully understanding that the Gribs will improve significantly as the target date decreases on passage.

As the Gribs are generally, in most areas, very good for 3 days or so, what am I going to get out of the synoptic chart that will change my passage plans?

I'm pretty good at weather. I'm not a meteorologist. I can go over gribs and lay in fronts, trofs, and ridges but it takes me a while. In addition, the meteorologists at the Ocean Prediction Center (where I have had the privilege of visiting) have a lot of information we do not have: weather balloon telemetry, radar and IR overhead, real time reporting from ships at sea, and a lot more.



If you are planning landfall a week out you are kidding yourself. Yes, you start looking and looking every day. When do you start doing something different? Two or three days out - better to slow down than heave to. You aren't doing that a week out.



Synoptics show fronts, trofs, ridges, highs, and lows you just don't get from gribs. You might decide to tack early to avoid a system that will be unpleasant. You might head one direction of another to stay in good air rather than drift or motor. You might change your meal planning because a front is going to pass dragged by a 998 low.



I just provided counsel to someone planning a brief passage tomorrow because the gribs looked good. A cold front (not in the gribs) and developing gale (not in the gribs) make tomorrow a bad day for that hop. He's going to wait until Thursday or Friday.

[DawnTreader]

Originally Posted by Auspicious

The 500 mb charts show the forces that steer sea level weather. For me they provide two benefits: QA on the surface forecasts and a heads up on what to expect at a macro level beyond the scope of current forecasts.



Synoptic charts over weather fax are a gift to cruisers. I simply don't understand why people use gribs when such better information is available.





Where are you? To my knowledge there is one place on the planet without good products.

Coming down the coast of Brazil, the Brazilian weatherfax was newly produced and was experimental and unreliable. Now in the Falkland Islands, perhaps Chile weatherfax could be received under the right conditions, but these charts are known to be out of date by the time they are distributed. I have not heard of any sailors using weatherfax on the Eastern side of South America, but maybe they are out there. I would take weatherfax if it were all that is available, but weatherfax is to predictwind as sextant is to gps. Both will get you there but one is more expensive, more accurate, and easier.

[Paul L]

Originally Posted by Auspicious

I'm pretty good at weather. I'm not a meteorologist. I can go over gribs and lay in fronts, trofs, and ridges but it takes me a while. In addition, the meteorologists at the Ocean Prediction Center (where I have had the privilege of visiting) have a lot of information we do not have: weather balloon telemetry, radar and IR overhead, real time reporting from ships at sea, and a lot more.



If you are planning landfall a week out you are kidding yourself. Yes, you start looking and looking every day. When do you start doing something different? Two or three days out - better to slow down than heave to. You aren't doing that a week out.



Synoptics show fronts, trofs, ridges, highs, and lows you just don't get from gribs. You might decide to tack early to avoid a system that will be unpleasant. You might head one direction of another to stay in good air rather than drift or motor. You might change your meal planning because a front is going to pass dragged by a 998 low.



I just provided counsel to someone planning a brief passage tomorrow because the gribs looked good. A cold front (not in the gribs) and developing gale (not in the gribs) make tomorrow a bad day for that hop. He's going to wait until Thursday or Friday.

I can generally see tbe fronts on tbe Grib displays. It shows up decently with the wind and pressure displayed.

I don't know what you mean by kidding yourself by planning a landfall a week out. That is exactly what you have to do when making many passages, like to and from New Zealand and Fiji of Tonga. Not looking that far out would be irresponsible. You see the systems working their way toward you - on the grib models - and plan accordingly. If you choose to leave, then you readjust as the models improve with decreasing days out.

[Discovery 15797]

Originally Posted by Auspicious

With respect you didn't learn to use them. How many cruisers dig into subjects like diesel maintenance, refrigeration repair, and no end of other topics but can't be bothered to learn about weather?

Slow boats make looking as far out as is reasonably reliable more important. You need more time to position your boat for the best weather available. That may mean tacking today rather than next Thursday in order to get the breeze you want (fuel conservation) or avoid unstable atmosphere (too much wind, rain).

I would suspect are much more knowledgable than myself regarding weather analysis and I appreciate your comments. However, you shouldn't assume what other people know or don't know. I used synoptic charts growing up in the Chesapeake, later flying and sailing in SE Asia, and also the Pacific Northwest prior to the plethora of modern apps available on the phone & iPad. My point was that I personally found the information downloaded each day from PredictWind provided me with a better overall "picture" for course routing purposes, and it was also easier to explain to my novice crew members.

BTW...I agree with you that any sailor who does not learn about weather prior to heading offshore is a chowderhead.

In my first-hand experience crossing the Pacific in August this year I looked 5 days out, but found that 3 days maximum provided the most reliable and accurate information for course routing since I was not following the traditional route, but instead on a rhumb line course. Also, this year the traditional "Pacific high" was not well defined and instead a patchwork of smaller highs spun up. I also kept the 5 day outlook to watch for lows developing off Mexico which could potentially develop into a late season storm (typhoon) that would cause me to alter course dramatically.

Which brings me to another point that I and others made. Climatic changes are occurring. The more information from multiple sources that you can gather and decipher will help with departure planning, and especially with route planning underway. Also, analysis of weather charts should be done on a daily basis.

These were my observations and experience this year. Your experience and your theater of operation may vary.

[conachair]

Originally Posted by Auspicious

Synoptic charts over weather fax are a gift to cruisers. I simply don't understand why people use gribs when such better information is available.

Seems completely daft not to use both. Great info in gribs, cape to show instability and a good indicator or the likelihood of thunderstorms, wind gusts far ahead of what I could ever predict from synoptics alone. Why just use one fairly vague source of the computer model output?

[Auspicious]

Originally Posted by Discovery 15797

I would suspect are much more knowledgable than myself regarding weather analysis and I appreciate your comments.

Relative knowledge remains to be seen. It isn't a contest. We share what we have.



I do look at gribs as well as synoptics but if I had to choose one it would definitely be synoptics. The biggest convenience of gribs is the interpolation the viewing tools do. The difference between precision and accuracy. More numbers do not mean correct numbers.

Originally Posted by Discovery 15797

BTW...I agree with you that any sailor who does not learn about weather prior to heading offshore is a chowderhead.

I didn't use that word but I strongly agree with your sentiment.



At the risk of digressing I'd say the same about people who don't understand radio: HF, VHF, Bluetooth, WiFi, GPS, radar, satellite phones.

Originally Posted by Discovery 15797

...provided the most reliable and accurate information for course routing since I was not following the traditional route, but instead on a rhumb line course.

I had a long discussion in 2005 with friend Herb Hilgenberg in which he made the observation that he saw two things that had changed: windward performance had improved on boats and a close reach was often the most comfortable, and second that in the Atlantic the Gulf Stream was moving South and weather was changing with that. Upshot - for transatlantics in both directions English Channel - Azores - Bermuda - Chesapeake was a better and better idea. That isn't to say that for Europeans aiming at the Caribbean the conventional route from the Canaries to St Lucia doesn't make sense. Between the EU and the US the rhumb (ish) line makes a lot of sense, and there is no good reason to take the more northerly route from days of yore.



Jimmy Cornell's updated pilot charts in World Ocean Atlas dropped out the statistical data from hundreds of years ago and deliver the same message.

Originally Posted by Discovery 15797

Also, analysis of weather charts should be done on a daily basis.

Darn tootin'.


Also worth noting that yesterdays 24 and the 48 from the day before are both tomorrow and changes in the forecast are useful information. You cannot get that from gribs.

[Paul L]

Originally Posted by conachair

Seems completely daft not to use both. Great info in gribs, cape to show instability and a good indicator or the likelihood of thunderstorms, wind gusts far ahead of what I could ever predict from synoptics alone. Why just use one fairly vague source of the computer model output?

Because the Grib model is easy and fast to download while offshore and includes the info I need to make any likely course changes on a passage. The Grib models, we use GFS offshore, are very good for 1-3 days and informative out to 7-10 days.

[jackdale]

Another good article on the 500mb analysis

https://www.yachtingworld.com/weathe...sailing-123478

[Auspicious]

Originally Posted by Paul L

I don't know what you mean by kidding yourself by planning a landfall a week out. That is exactly what you have to do when making many passages, like to and from New Zealand and Fiji of Tonga. Not looking that far out would be irresponsible. You see the systems working their way toward you - on the grib models - and plan accordingly. If you choose to leave, then you readjust as the models improve with decreasing days out.

I suspect we are using vocabulary differently.



I watch weather as far out as I can with due regard for decreasing confidence further out in time. Sure, I have a running estimate of arrival time. I don't do anything different as a result of that estimate a week out. That is what I mean by not planning landfall too early. I go as fast as I can as comfortably as I can. The balance between those two depends on whether I'm cruising or on a delivery. There are just too many things that can and do change a week out.



About three days out I start thinking about slowing down. That might be to run an inlet with the sun high and behind. It might be driven by tides or currents. It might be missing concentrated commercial traffic (such as rush hour ferries in New York Harbor). If I need to burn twelve hours three days out I may slow down enough to burn a third of that three days out. If nothing goes wrong I'll slow down more two days out. If nothing goes wrong I'll slow down more a day out.



If you slow down a week out to push out twelve hours and the wind fills in you'll have trouble getting that lost time back and end up having to slow down yet more. If the wind fails (which it might but you can't count on) you can end up a whole day behind.



Monitoring really early? Of course. Taking action on the basis of observations and other data too early? No.


Our disagreement, to the extent it exists, may be as simple as how we use the word "plan."

[Paul L]

Originally Posted by Auspicious

I suspect we are using vocabulary differently.



I watch weather as far out as I can with due regard for decreasing confidence further out in time. Sure, I have a running estimate of arrival time. I don't do anything different as a result of that estimate a week out. That is what I mean by not planning landfall too early. I go as fast as I can as comfortably as I can. The balance between those two depends on whether I'm cruising or on a delivery. There are just too many things that can and do change a week out.



About three days out I start thinking about slowing down. That might be to run an inlet with the sun high and behind. It might be driven by tides or currents. It might be missing concentrated commercial traffic (such as rush hour ferries in New York Harbor). If I need to burn twelve hours three days out I may slow down enough to burn a third of that three days out. If nothing goes wrong I'll slow down more two days out. If nothing goes wrong I'll slow down more a day out.



If you slow down a week out to push out twelve hours and the wind fills in you'll have trouble getting that lost time back and end up having to slow down yet more. If the wind fails (which it might but you can't count on) you can end up a whole day behind.



Monitoring really early? Of course. Taking action on the basis of observations and other data too early? No.


Our disagreement, to the extent it exists, may be as simple as how we use the word "plan."

I doubt there's much disagreement. Although I certainly look out 5-10 days to guess at what the arrival weather will be before pulling the trigger to leave. Looking for serious fronts that might arrive at the destination as we go to higher latitudes, or perhaps closed lows that might be approaching the tropical latitudes.

I also don't slow down anywhere near as early as you do. Been burned too many times with very light winds for the last 24 hrs. It is too easy to slow down on the approach, say the last 60 miles.

[Auspicious]

Originally Posted by Paul L

I doubt there's much disagreement. Although I certainly look out 5-10 days to guess at what the arrival weather will be before pulling the trigger to leave. Looking for serious fronts that might arrive at the destination as we go to higher latitudes, or perhaps closed lows that might be approaching the tropical latitudes.

I also don't slow down anywhere near as early as you do. Been burned too many times with very light winds for the last 24 hrs. It is too easy to slow down on the approach, say the last 60 miles.

As I suspected - vocabulary is important.



I'm absolutely with you about fronts. For my vocabulary I consider that part of the transition from route planning to passage planning. I've moved a lot of boats out of Northern ports that were delayed by work being done. Cold is enough of a challenge without adding weather disruption.



I use synoptic charts over gribs so I haven't been surprised perhaps as often by light winds. I still get them of course, but I know they are coming and account for that.



Now when to slow down and how much and on the basis of what information would be a very interesting discussion, at least for me. For many people perhaps not so much. *grin* I'd definitely rather slow down than heave to, but I don't want to risk missing a window by 12 or even 24 hours to enter a port.



What I like may not always align with what other people are after. Most of us can probably agree on entering tropical inlets with the sun high and behind. Big commercial ports like Fort Lauderdale, Charleston, Chesapeake Bay, and New York I rather like at night - less busy, less recreational traffic, and the commercial guys out there assume you have some modicum of sense if you're out there in the dark with them. YMMV.

[Paul L]

Originally Posted by Auspicious

.......



I use synoptic charts over gribs so I haven't been surprised perhaps as often by light winds. I still get them of course, but I know they are coming and account for that.
.

I know you much prefer the synoptic charts over the grib models. For where we do passages I have not seen the advantage. As you approach the island land masses, neither one is good. Even in places that have excellent, highly skilled forecasters like when you approach New Zealand after on a 7-10 day passage, the joke is that the Kiwi forecasters always get the weather right because they change the forecast ever two hours.

Originally Posted by Auspicious

Now when to slow down and how much and on the basis of what information would be a very interesting discussion, at least for me. For many people perhaps not so much. *grin* I'd definitely rather slow down than heave to, but I don't want to risk missing a window by 12 or even 24 hours to enter a port.
......

That's why I don't make speed adjustments till the last 24 hours. At that point I know how far away we are and have a high bet on what the weather will be. Three days out and your forecast is far less reliable.

[Auspicious]

Originally Posted by Paul L

I know you much prefer the synoptic charts over the grib models. For where we do passages I have not seen the advantage. As you approach the island land masses, neither one is good. Even in places that have excellent, highly skilled forecasters like when you approach New Zealand after on a 7-10 day passage, the joke is that the Kiwi forecasters always get the weather right because they change the forecast ever two hours.

Agreed. Land effects including katabatic winds and thermally driven winds make a difference near islands. In my experience those are generally predictable from the macro-level synoptics and the navigational charts.



The flip side of Kiwi forecasters are the guys in the BVI who record a forecast in February and play it every day until August. *grin*

Originally Posted by Paul L

That's why I don't make speed adjustments till the last 24 hours. At that point I know how far away we are and have a high bet on what the weather will be. Three days out and your forecast is far less reliable.

I mostly agree. Still, if it looks like I want to push my arrival time by twelve hours from three days out and to do so I need to slow down by a knot, I might ease a sail a bit and slow down a couple of tenths. Tomorrow I might, with updated weather, slow down a tiny bit more. Yes I could wait longer and adjust more, striking a sail completely, but then I have to think about sail balance and autopilot performance and power consumption. This is all the flip side of my mantra of 'sail fast and eat well' - keep the boat moving as fast as you can until you don't have to anymore. I don't suggest hovering over the winches but you (generically) should be looking at the sails with every horizon scan anyway looking for chafe, that batten sticking a foot out the back of the sail, etc. Hmm - the VHF antenna is dangling from the masthead. That isn't good. So adjust the sails when you see the telltales telling you to do so. Sorry for ranting.



In this respect the ETA display on electronic navigation really tells the tale. With a waypoint half an ocean a way, five minutes of attention to sail trim can carve a day off the passage. All things being equal (and sometimes they aren't) that is good. My crews really get the message then and pay more attention to keeping the boat moving. Sure, I could tolerate poor trim and make more money but that isn't in my customer's interests. When cruising myself I work the same way - keep the boat moving. Better sail trim leads to longer sail life. *sigh* I'm ranting again, aren't I?