The (Official) "Lets Bash the Nina Thread" - sponsored by Bazzer :-)

[barnakiel]

Originally Posted by bazzer

(...)

a) Seems our armchair sailors know more than the NZ SAR.

b) Just when will one of them come to the realization that Nina and her crew are most certainly lost.

c) IMHO the boat should have never left of a open ocean voyage in the winter in the first place.

d) I most certainly would not have left in any small boat.

e) But who am I to judge? I've only got sixty years of sailing experience.

Ad:

a) (Re: who knows better) Right. But ours is post factum knowledge. NZ SAR had the best knowledge available to them at that time.

b) Hope dies last. And they may well still be alive. Most certainly is not quite definitely.

c) IMHO many boats depart from NZ May/June. When did she leave?

d) She is not a small boat.

e) Her skipper/crew do not sound like a bunch of greenhorns either.

If there are sailors at Forum that are armchair sailors then it only makes our forum a better and more varied place. Please spare them language like "our armchair sailors". To me, it sounds rude towards the less traveled members.

There is a study which shows that 'experts' who are damn sure of their expertise are more likely to be wrong than people who are less certain of their infallibility.

Cheers,
b.

[opusnz]

What latitudes are the winds west to east? Only when you go far south is it that direction. There is no real prevailing winds around the area where Nina went missing if you look at the pilot charts..... SW may be common but it really varies as the fronts come through. If anything, Nina was on the southern edge of what is normally the SE trade winds. If she eased north or NW after the storm, she should have had the prevailing SE winds.

[Captain Bill]

Originally Posted by opusnz

What latitudes are the winds west to east? Only when you go far south is it that direction. There is no real prevailing winds around the area where Nina went missing if you look at the pilot charts..... SW may be common but it really varies as the fronts come through. If anything, Nina was on the southern edge of what is normally the SE trade winds. If she eased north or NW after the storm, she should have had the prevailing SE winds.

I have a degree in Marine Science wich includes Oceanography and Marine Biology so I'm not an armchair sailor, I'm a retired marine scientist. Generally the atmosphere is divided into three bands based on lattitude in each hemisphere. In the tropics the air rises near the equator and decends near the edge of the temperate zone. Air on the surface of the tropics moves towards the equator and is turned to the right in the northern hemisphere and to the left in the southern hemisphere by the corriolis effect. This is what forms the tradewinds which blow from east to west. In the temperate zone winds tend to move away from the equator and again are turned by the corriolis effect and tend to blow from west to east. This is why weather systems move from west to east in the temperate zones in both hemispheres. While winds may be locally from any direction for a short period, the prevailing winds and net movement of the air in the temperate zones always nets out from west to east in the long term. The line between the temperate air movement and the tropical air movement moves towards the equator in winter and away in summer. There are periods especially in the summer where large high pressure systems tend to block lows and cause them to move away from the equator. They move around the highs but always have a net movement to the east. NZ, southern OZ and the Tasman sea are all in the temperate zone. If for some strange reason there was a long term blocking high in the winter, then the current would dominate. From the charts that I've seen the predominant current directions are south or east depending on exactly where you are in the Tasman.

It may be possible that they have an intact rig and are averaging less than 1 knot vmg. I just think it highly unlikely. If they were moving under a jury rig or bare poles downwind they would have been back in NZ before the search even started. If the rig as any significant problems going to windward is almost impossible. If the are in a raft or drifting in a disabled boat, their net movement will be easterly. If they are sailing to OZ under a reduced rig then they'll showup somewhere and won't need rescued. If one is assuming that they need aid then looking for them in the direction of OZ is significatly reducing their odds.

[Seaworthy Lass]

Originally Posted by Captain Bill

......If the are in a raft or drifting in a disabled boat, their net movement will be easterly. If they are sailing to OZ under a reduced rig then they'll showup somewhere and won't need rescued. If one is assuming that they need aid then looking for them in the direction of OZ is significatly reducing their odds.

Hi Captain Bill
I know that SY Windigo was abandoned further north (between NZ and Tonga) at a different time of year (November), but she washed up on the NSW north coast about 4 months later.

How does that fit in with your theory about general air movement and current in the Tasman?

[opusnz]

Well I am no marine scientist but I have spent enough time in the Pacific to know that the prevailing wind in the tradewinds is east to west either side of the ITCZ....either NE or SE. That is why people sail around the world east to west and not the other way. Nina was really in a temperate transition zone with a lot of fronts and then variable winds but it can also be argued that Nina was on the southern edge of the SE trades. If she managed to get further north, I still think she would have ended up either N or NW.

I know people who have sailed east from Aus to New Caledonia, Fiji, or Tonga and it can be a very difficult trip hard on the wind. The easier way to make the trip is to go much farther south towards Sydney, Aus and pick up the South Australia current and hopefully some SW winds and then head to NZ.

[giant]

I don't understand why they left NZ when they did. It was at a time when Australia's infamous east coast lows where forming in the Tasman Sea into their most extreme of the season, one would have to have been expecting winds well over 55 knots.

Maybe if you had a 70 foot super duper steel wonder boat with several watertight bulkheads etc etc like I have seen in Stahan, Tassie but in a historic old wooden relic....

Seems like another case of people having "deadlines" to adhere to. Sailing to a schedule can prove fatal.... beware.

An armchair sailor with 12 000 miles at sea.... not huge but not too small either. Bracing to be flamed.

[s/v Jedi]

Originally Posted by giant

I don't understand why they left NZ when they did. It was at a time when Australia's infamous east coast lows where forming in the Tasman Sea into their most extreme of the season, one would have to have been expecting winds well over 55 knots.

Maybe if you had a 70 foot super duper steel wonder boat with several watertight bulkheads etc etc like I have seen in Stahan, Tassie but in a historic old wooden relic....

Seems like another case of people having "deadlines" to adhere to. Sailing to a schedule can prove fatal.... beware.

An armchair sailor with 12 000 miles at sea.... not huge but not too small either. Bracing to be flamed.

No, I agree with you that the schedule is the core source of the problem. Time lost with replacing engine, hurry, hurry. I see this happen all the time but find that warnings don't help like if their ears do not capture the words. It's like a horse with those flaps besides the eyes so they can only look (go) forward.

[psneeld]

"prevailing" winds are nice to think about...

checked the monthly recorded wind patterns for Jun/July 2013 in Wellington, NZ and Canberra, Au and it seems the predominant winds were North and then South by half with little or no East/West winds. While I know these are both land stations...the strength of the wind suggests the direction is pretty accurate.

[MarkJ]

Originally Posted by Seaworthy Lass

Hi Captain Bill
I know that SY Windigo was abandoned further north (between NZ and Tonga) at a different time of year (November), but she washed up on the NSW north coast about 4 months later.

How does that fit in with your theory about general air movement and current in the Tasman?

You need to look at the pilot charts.
Windego was abandoned MUCH further north. The current there goes towards Australia then the East Coast Australian current goes south.

in the north the current is exactly 180 degrees different than the top of NZ. One goes west, one goes east.

The wind too is different. In the north its easterly; in the south westerly

[Captain Bill]

Originally Posted by Seaworthy Lass

Hi Captain Bill
I know that SY Windigo was abandoned further north (between NZ and Tonga) at a different time of year (November), but she washed up on the NSW north coast about 4 months later.

How does that fit in with your theory about general air movement and current in the Tasman?

This fits perfectly with my point. As I said (maybe not clearly) the line between the west to east wind in the temperate zone and the east to west winds (trades) in the tropics moves closer to the equator in winter and away from the equator in summer. Windigo was pretty obviously caught in the summer trades and moved west. Being futher south and in Winter there is pretty much no chance of the Nina or a raft showing up in Oz while drifting. If it ever ends up in OZ it will be because it has drifted east into the humboldt and then was pushed north by the current into the trades and then drift back west on the trades. This however will take a long time, perhaps a year or more. I am a pilot as well as a sailor and mostly in the US Mid-atlantic. When flying I almost always have a headwind while heading west and a tailwind while heading east. The US midatlantic is roughly in the same zone north of the equator as NZ is south. When a front comes through here in winter the west winds are always much stronger than the east win ds experienced after the front passes. In the winter here we get a strong SW wind before the front and strong NW wind immediately after the front. In between the wind weakens and clocks around to a lighter NE wind and a very light SE, before switching back to a strong SW before the next front. Because we are on the east coast of the US we are more like the SE coast of OZ rather than NZ as lows tend to form along our coast and nove off to the east or NE. Of course being the southern hemisphere winds are NW in before the front and SW after the front. Generally though the stronger winds will come from the west and lighter winds from the east. Net movement is from west to east. If that wasn't true the lows in the Tasman would move from east to west, which they don't do. Note that tropical cyclones move from east to west because they are moved by the east to west winds in the trades. Once they drift far enough north or south of the equator they get caught in the westerlies and moves away from the equator and recurve to the east.

[MarkJ]

I think Bill's thoughts are right and I made a similar point in the main thread on 30th June

Hmmmmm but the current heads to the east....

the green arrows show the direction of the current.

Things can be blown by the wind or the current depenting on the nature of each. But a dismasted full keel yacht (or life raft with drogues) 50NM north of North Cape should have gone with the current... to the east... at 5 to 10 nms per day... and would now be 100 nms NE or 260NM E of North Cape.

The SAR guys would have factored it all in, but you could just check with them and make sure they have.

Using the below attached shot of a pilot chart.

Using the figures above and Bills assumptions = 540nms E of NZ about 34 S 176 W.
using Bills figures of aprox 1 kt = 24 miles per day since the storm = 1200nms = 34 S 162 W
Still in the westerly winds and an east setting current.

If east of NZ the possible area is huge. Unimaginably huge. So, one must then return to the original facts and say that the failure of all three electronic communicators at once: EPIRB, sat phone and Spot leads to the conclusion it sank 'catastrophically' close to its last known position.

By the way, as Bill noted, plot the locations and then see its a further 4,000nms to Chile and then the Humbolt heads north for another lap.


Mark

[opusnz]

I can't believe so many people think the drift would be east....

There have been two boats abandoned near NZ in recent years. Scotch Bonnet in the middle of the Tasman and Windigo between NZ and Tonga. Scotch Bonnett was sited near Norfolk Island (not that far north of Nina's last known position) but ended up months later on an Aus beach.

Pensioners try to claim ghost ship Local Gold Coast News | goldcoast.com.au | Gold Coast, Queensland, Australia

Windigo, although abandoned east and north of NZ, ended up near Coffs harbour.

[Captain Bill]

Originally Posted by MarkJ

I think Bill's thoughts are right and I made a similar point in the main thread on 30th June



Using the below attached shot of a pilot chart.

Using the figures above and Bills assumptions = 540nms E of NZ about 34 S 176 W.
using Bills figures of aprox 1 kt = 24 miles per day since the storm = 1200nms = 34 S 162 W
Still in the westerly winds and an east setting current.

If east of NZ the possible area is huge. Unimaginably huge. So, one must then return to the original facts and say that the failure of all three electronic communicators at once: EPIRB, sat phone and Spot leads to the conclusion it sank 'catastrophically' close to its last known position.

By the way, as Bill noted, plot the locations and then see its a further 4,000nms to Chile and then the Humbolt heads north for another lap.


Mark

Exactly right Mark. The other problem is that there are not many ships crossing that part of the Pacific, so they have little chance of being found accidentally. Their best hpoe is that they are in a demasted boat that is damaged but afloat. Waters down there are not exactly warm this time of year. If they are in the raft they are in deep trouble if they are still alive. The raft is fast approaching two months old. Most of the raft survival stories I have read indicated the rafts were beginnning to fall apart by two months. I will be amazed if they are ever found and they'll have to rewrite the oceanography books if they are found west of NZ.

[MarkJ]

Originally Posted by opusnz

I can't believe so many people think the drift would be east....

There have been two boats abandoned near NZ in recent years.

.

Windego was NOT abandoned near NZ. They were on passage TO NZ from Tonga and were much closer to Tonga. They were in the current that sets towards the west.

Nina was in the area much farther south in the current that sets to the east. Even the winds are different.

Please grab a pilot chart and have a look.

I have attached the pilot for July.

[Captain Bill]

Originally Posted by opusnz

I can't believe so many people think the drift would be east....

There have been two boats abandoned near NZ in recent years. Scotch Bonnet in the middle of the Tasman and Windigo between NZ and Tonga. Scotch Bonnett was sited near Norfolk Island (not that far north of Nina's last known position) but ended up months later on an Aus beach.

Pensioners try to claim ghost ship Local Gold Coast News | goldcoast.com.au | Gold Coast, Queensland, Australia

Windigo, although abandoned east and north of NZ, ended up near Coffs harbour.