The GGR race, discussion and news

[Snowpetrel]

^^Also they are only getting weather via HF radio. No gribs, so we have a much better and clearer picture of what is happening than they may have.

[picklesandjesse]

Originally Posted by Jim Cate

Having spent some time aboard the "real" Joshua, I'm bloody glad to be in my current boat in the extant time frame!

Comfy she was not...

Jim

Turn that heater on Jim.... was 0 degrees here this morning. might be not much better up there. 2nd coldest day ever !!! that's Global warming for you.

[GILow]

Originally Posted by Snowpetrel

^^Also they are only getting weather via HF radio. No gribs, so we have a much better and clearer picture of what is happening than they may have.

So, are you saying the HF radio weather transmissions cannot be interpreted in such a way by someone skilled in the process that they are not as useful as gribs?

Serious question, because I am learning how to read those charts at the moment in anticipation of needing them myself.

[El Pinguino]

Originally Posted by GILow

So, are you saying the HF radio weather transmissions cannot be interpreted in such a way by someone skilled in the process that they are not as useful as gribs?

Serious question, because I am learning how to read those charts at the moment in anticipation of needing them myself.

Well... depends entirely on what they are actually getting...

This is the text and possibly also the vox that you get from NZ for the Sopac https://www.metservice.com/marine-su...h-seas/pacific ... someone handy with a 2B will get all they need out of that... and the interpretation has already been done for you... you have to interpret your own gribs.



If they are getting fax from Cape Naval they would be getting synoptic charts like the one buried in here... Meteo Cape Town

I'm not sure how this info is promulgated http://www.weathersa.co.za/media/data/marine/ma_hs.pdf
but at the end of the day it probably gives you all you need..

You can overthink this stuff.....

[conachair]

Originally Posted by GILow

So, are you saying the HF radio weather transmissions cannot be interpreted in such a way by someone skilled in the process that they are not as useful as gribs?

Serious question, because I am learning how to read those charts at the moment in anticipation of needing them myself.

Give it a go, no way can I get near the accuracy of gribs from synoptic looking at actual data. Though that's closer to the coast, maybe mid ocean there's less in it.
Just how much it actually matters is another thing, big picture info is there, just the wind speeds can vary even f the synoptic isobars look near identical.

[Bleemus]

Gribs are the raw output of models.

Synoptic weatherfaxes are meteorologists interpretation of the models.

I prefer the latter.

[conachair]

Originally Posted by Bleemus

Gribs are the raw output of models.

Synoptic weatherfaxes are meteorologists interpretation of the models.

I prefer the latter.

Ever spent a few weeks trying to match the accuracy of gribs against actual wind data using just the synoptics?

Bet you couldn't

[Snowpetrel]

Originally Posted by conachair

Give it a go, no way can I get near the accuracy of gribs from synoptic looking at actual data. Though that's closer to the coast, maybe mid ocean there's less in it.
Just how much it actually matters is another thing, big picture info is there, just the wind speeds can vary even f the synoptic isobars look near identical.

I am with you. Even with years of using synoptic charts I still struggle to accurately guess the wind speed with anywhere near the accuracy of a grib. I tend to use the voice forcasts for windspeed.

In there case they aren't even getting a proper synoptic chart. Back in the old days I used to make my own weather charts offshore from the voice HF forcasts. They were pretty slow to make and rather vague a lot of the time. Giving positions of major features, Highs, lows, fronts and a few data points. But plotting reliable isobars and isobar spacings wasn't really possible.

Areas of strong winds were given with approximate boundarys but it was all rather vague and often required a fair bit of guess work as far as the actual isobars went around complex systems. It was much much better than nothing, but no comparison to a weather fax.

Not sure what they are actually getting but grib files make it pretty easy for us to visualize the situation. For them it may be much less clear exactly what is going on.

Here is some of the maths behind it. But Isobar curvature stuffs it all up.

[Snowpetrel]

Originally Posted by GILow

So, are you saying the HF radio weather transmissions cannot be interpreted in such a way by someone skilled in the process that they are not as useful as gribs?

Serious question, because I am learning how to read those charts at the moment in anticipation of needing them myself.

You can get weatherfax synoptic charts easily enough with something like blackcat on an ipad or Phone or JVcomm32 on a pc.

They don't have any weather fax systems onboard. So every chart has to be hand plotted and the very broad area forcasts interpreted. It may be that their HF contacts are giving them more locallised forcasts, but it would be hard to give much detail about the bigger picture without routing them.

[Snowpetrel]

Originally Posted by El Pinguino

I'm not sure how this info is promulgated http://www.weathersa.co.za/media/data/marine/ma_hs.pdf
but at the end of the day it probably gives you all you need..

You can overthink this stuff.....

This is probably all they are getting. Have a go at drawing it and see how it looks. A great training exercise for you Matt, and a useful skill, because all you need for this is a cheap HF reciever with a decent Beat frequency ocillator.

Here is the aussie one from here
http://www.bom.gov.au/marine/high-seas.shtml sea area western. Remember this all needs to be written down by hand over a scratchy HF signal. Shedule here http://www.bom.gov.au/marine/radio-s...hf-radio.shtml

If they are smart they will have a tape deck to record it so they can write it down while pausing and rewinding it as need be.

High Seas Forecast for Western METAREA 10 WESTERN AREA: COAST AT 129E TO 50S129E TO 50S80E TO 30S80E TO 30S90E TO 12S90E TO 12S125E TO COAST AT 125E

Melbourne Gale Warning 2. Melbourne Gale Warning 3. Part 2 Situation at 0600 UTC Refer to latest warnings for boundaries of affected areas and type of weather systems. Cold front [1] 30S114E to 34S122E to low 1001hPa near 42S123E to 45S121E to 50S126E. Forecast 35S137E to low 1001hPa near 37S131E to 43S131E to 50S140E at 221200UTC. Cold front [2] west of area and forecast 42S071E 50S086E at 211200UTC and 40S080E 41S089E 50S107E at 221200UTC. Part 3 Forecast Refer to latest warnings. South of line 35S080E 42S114E 49S129E, outside warning area: Westerly quarter winds 20/30 knots, turning northwesterly quarter within 600nm east of cold front [2]. Wind speeds increasing to 20/33 knots within 120nm of warning area. Rough to very rough seas. Moderate to heavy swell, increasing to heavy west of cold front [2]. Remainder south of 30S, outside warning areas: Northerly quarter winds 20/30 knots within 240nm east of cold front [1], turning clockwise within 360nm of low. Southwesterly quarter winds 20/30 knots within 480nm west of cold front [1]. Winds speeds increasing to 25/33 knots within 120nm of warning area. Rough to very rough seas. Moderate to heavy swell. Northwest of line 12S102E 25S102E 25S090E: Southeasterly trade flow 20/30 knots. Rough seas. Moderate swell. Remainder: Winds below 25 knots with slight to moderate seas. Moderate swell, increasing to moderate to heavy south of 26S. Rain areas, scattered showers and isolated thunderstorms within 240nm of cold fronts and 300nm of low. Isolated to scattered showers north of 30S. Visibility reducing below 2nm in precipitation. WEATHER MELBOURNE The next routine forecast will be issued at 21:00 UTC Tuesday.

[Terje Vigen]

Naturally it is very important for the sailors to position themselves as best as they can relative to the wind systems.
It is also important to position themselves favorable relative to the ocean currents.

[Snowpetrel]

^^ Don has put a fleet wide warning out about those currents. Seems to me that having good current flow information may be as important or even more so than accurate forcasts. A good discussion by Vdh on soundcloud. And also a likely lifting of the 44 limit to 42 east of 40E.

Philipe Peche is pretty pissed off.. Don does a good job (as always) of dealing with it. I've always been inpressed with Dons calmness. PP is really not sure what he is going to do.

Really enjoyed Capt Coconuts chat. He loves to talk, even outdid Don, now thats a feat! And I also enjoy Mark Slats talks. They have some better weather info now. A guy out of south africa is giving them more detailed 3 day info.

Strong winds on the way..

[Jimroda06]

See you on the start line Pickles, 2022, I'm 73.

[El Pinguino]

Hmmmm.... I'm seeing a bit to much overthinking and possibly 'over regulating' in this race...

Re the over regulating... if the rules are changed post start to limit them to 42*S rather than 44*S that could push them into highs, calms and easterlies , if they were E of 40*E just now that is exactly what would be happening. Pic Uno..

Overthinking..?

There is a zone of high pressure in the South Atlantic.... southerlies to the right... northerlies to the left... not very much in the middle... always so....
Only vdH pulled the 'direct track' off successfuly.... half of the rump is still banging around in the high... as Goodall expressed it 'light winds and confused seas'....

Meanwhile Captain Coco enjoys a fair breeze... no wear and tear on the boat or the skipper....

Currents? Pic 2 When the current is variable and below 0.2 knots I would be far more interested in the wind....

And also.... what access do they have to current current info? Nil I would have thought...

[Snowpetrel]

Tapio has a big battery issue. Talked about 9 volts. Thats low... I am surprised they are having so many issues with charging as they have big battery banks and a lot of solar. Prehaps one of his battery cells has died, sucking the whole bank down. A key part of this event will be having the ability to fix stuff.

Can't think what big draws those boats have? And it doesn't take much solar to keep up with basic LED nav lights. I have managed with one 20 watt panel before. Either a dead cell or a leakage somewhere. Engine won't run. Possibly they are linked somehow.