Cruising resource: A global pseudo-real time wind map

BCC Forum
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Point your browser to: http://earth.nullschool.net/#current/wind/isobaric/1000hPa/orthographic=-235.51,-1.99,801

You’ll see wind streams in the geography of interest to Zygote - the Northeast Monsoon stream running down the East Asian coast and spilling across the Equator to become the Northwest Monsoon in Australia. Note Tropical Storm Jane, centred near New Caledonia, and for which I did a little weather routeing support for the Russian cruisers I mentioned a few posts back (they should now be docked in Opua, New Zealand).

You can of course grab the map with your pointer/mouse/trackball and recentre it wherever you desire.

Technology!

Bil

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Good Gosh Bil , Joy at Last !!! That site is now on “My Favorites” , Such a Great Discovery !!!

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Blow me down!

The net has an older pseudo-real time wind map for the lower 48 states at:

http://hint.fm/wind/

And a multifunctional wind map for the Kanto/Greater Tokyo area that also allows stepping forward and back in time, and adding coloration for solar insolation, air temperature, and NO, NO2, NOx pollutants, humidity, and wind speed at:

Bil

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And now, for something different, ocean currents!

These are east of Zygote’s home base in Moreton Bay, Australia:

http://earth.nullschool.net/#current/ocean/surface/currents/orthographic=-203.98,-26.96,3000

You can of course drag the surface of the planet to almost wherever you choose!

Late edit: the ocean current model is updated only every 5 days. See http://earth.nullschool.net/about.html

Cheers

Bil

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To summarise on the resources available (and growing):

Point your browser to: http://earth.nullschool.net/

You’ll see the globe at a relatively small-scale projection, with the word ‘earth’ in the lower left.

The word ‘earth’ is the key to the control. Click on it.

You can then choose among which wind model you want (GFS etc).

You can choose between the wind or the ocean current model.

For the wind, you can choose Surface, 1000 hPa etc.

You can add overlays, including for Total Precipitable Water.

You can choose English or Nihongo/Japanese.

You can of course rotate the globe, choose the projection, zoom in (should you have a wheel on your pointing device) and click on currents/wind streams for velocity (direction, speed) data.

The wind model is updated every 3 hours. The ocean current model is updated every 5 days.

Bil

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Thanks Bil, good data is always appreciated.

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Hi Bill < love this site. Thanks for putting it on the forum. I’m hoping to get down to Whitewings3 this weekend. Not sure how the weather has been up your way, but its pouring down here. Looks like the drought has broken.
I dived WW3 the other weekend and gave her a scrub. She is even lovelier underwater than she is above. All going well. I will try those rig numbers you gave me and give her a tune. Was out in about 30 knots of sw the other week. Single reef in the main and just the jib. Should have gone for a second reef in hindsight, still plenty of fun and she took it in her stride.

Regards Shane WW3

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bil if you are giving out rigging numbers I would love a copy

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Stewart: Hi!

Tom Harrer (peace be upon him) of White Wings III and I worked both on this forum and by e-mail to come up with target figures for standing rig tension.

Tom had the practice of pulling the mast of WWIII at the end of each season, because the water in the Great Lakes turned solid. So being able to replicate pretension in the rig reliably at the start of a new sailing season was important. I was interested in pre-tension that would minimise working or pumping by the bowsprit and mast. Tom loved sailing WWIII to her top performance, so he and WWIII tested close hauled performance and concluded that it was not compromised by the tension.

Tom and I recognised that rig tension does not necessarily deliver better on-the-wind sailing performance (in other words, yes, I’m familiar with scientific tests showing that slack rigs can beat to weather as fast if not ever so slightly faster than tight rigs due to beneficial effects of forestay sag in certain conditions). It’s the rig and sail geometry, not the pre-tension in the shrouds and stays, that is decisive for performance. The pre-tension is to stabilise the spars and keep them in column. Masthead rigs are built for pre-tension. BCC hulls are built to take the pre-tension. Don’t try this with a lightly built hull and a fractional rig.

Tom and I used Loos gauges - the less expensive ones, not the professional models. And we talked in Loos gauge figures, not pounds.force or kg.force. The gauges do have a table that converts between gauge figures and pounds.force. Some of the figures are a range, not a single figure - that’s when we couldn’t find any difference in performance etc.

A determined search of the forum should find some of our conversations. But to make things quick (now that I’ve put the qualifications on the record), here are figures for your guidance (not to be worshipped):

Whisker stays: 37 - 39
Staysail stay: 42
Cap shroud: 41
Intermediate shrouds: 39
Lower forward shrouds: 37
Lower aft shrouds: 37
Backstay: 47

Any one Loos gauge should deliver repeatable tensions. Loos quotes accuracy figures of + or - 3% at mid-range of the scale of a gauge and + or - 5% over the range of the scale.

In the forthcoming version of Zygote’s word list you’ll find mention of Augustus W. Loos, the founder of the company, and Donald J Jordan who invented those inexpensive tensiometers.

In all her years of sailing with those rig tensions, including in a few nasty squalls and rough ocean conditions, Zygote has shown no stress in her GRP. She does show some stress in her 316 stainless steel chainplates. And I am working towards replacing those chainplates. I do not attribute the stress in the chainplates to the rig tensions.

Cheers

Bil