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Home / Newsletters / Newsletter September 2020
Home / Newsletters / Newsletter September 2020

Newsletter September 2020

Future Events We have a busy calendar between now and Christmas, and more details will be provided as each event approaches, taking into account any Covid restrictions at that time.

  • 13 September Hibiscus Marine Coatings Race 8, 1300
  • 18 September Quiz Night and Photo Competition, 1800
  • 23 September Annual General Meeting, 1930
  • 27 September Hibiscus Marine Coatings Race 9, 1400. Results and Series Prizegiving at GHYC after the race.
  • 29 September Club Spring Clean from 0900
  • 30 September Reserve Spring Clean day
  • 3 October Ponsonby Cruising Club visit & dinner
  • 4 October Boat Bits Bring 'n' Buy and Car Boot all-sorts sale, 0900

From the Vice Commodore

So as the Commodore waves us a cheery goodbye as he heads off to Canada, to do stuff on the Naval Frigates currently undergoing upgrades, his parting shot (not literally) was " can you do the next two newsletter, Col?"

You'll be relieved that this number 2 in a series of 2.

Isn't life a tad unusual at the moment? It's all gone a bit weird and out of control. Do you put on a face mask when walking down the jetty? What about when you meet someone who isn't wearing a mask, on the narrow walkwaydoes one of you have to bypass down a finger to let the other one pass with 2 metre clearance.

Does this apply to the race start line? Is the shout of water been substituted by "please keep two metre separation" Does it all get polite..

Never mind masks, what about gatherings? Small groups of 10, and no more of hundred.unless someone present has recently passed away then it's groups of 50. (or is that 51?)

Electionsdon't get me started. Politicians flying all round the country doing their best to spread the dreaded bug. Admin; we have deleted a paragraph that was full of political innuendos .

The stock market is up through the roof, and on the other hand we're heading for negative interest rates. Please explain that to me.

The Americas Cup is imminent, and make a mental note that we will be running live videos in the club in conjunction with a few other local marine businesses. That'll be fun. However on the other hand I heard that currently no superyachts are scheduled to be in town, as the owners can't travel. That's not good for the industry.

ANYWAY we can get back on the water, so the world is good.

Finally I hope I haven't given away a defence secret with the opening sentence.

Have fun.

Colin Mitten

Welcome to our New Members

Hi, we are Alan & Diane Beck and we moved to Gulf Harbour last year after 20+ years of living on a lifestyle block on the North Shore. We have kept boats for all of those 20+ years on the GH marina and we currently own a Ron Given power cat. However, our boat is currently on a mooring in the Bay of Islands! Something we seriously need to address now that we live here in GH!! We are originally from UK, spent 23 years in Malawi, Brunei and Dubai before moving to NZ in 1998. We are joining primarily as social members but also look forward to sharing boating experiences with you all.

Julie and Simon Whitehead came to NZ from Portsmouth UK. Julie is working in the city as midwife and Simon is working at Gulf Harbour Marina as part of the maintenance team. Simon is keen to learn more about sailing and would enjoy opportunities to crew. They are about to purchase a small sailboat to use locally and gain confidence with sailing. Simon had a small boat in Portsmouth and wants to learn as much as he can re sailing whilst living at Gulf Harbour.

Carol and John Laidlaw own the yacht Touché and have owned her for over 24 years. They have been sailing for over 40 years in Australia and New Zealand. Their business is Trans Pacific Marine Limited.

Marcia and John Krska were totally new to boating when they emigrated to NZ from Scotland in 2011. On arrival, learning to sail was top of the list. Bought a Macregor power sailer at the 2012 Auckland Boat Show, joined the NZ Yacht Squadron in Westhaven & took part in some training courses. Now retired, and in anticipation of creeping old age, now have a Sea Ray Sundancer 260, berthed in L49. Marcia is totally passionate about her boating and would spend every day on the water if she could. Recently achieved her Boatmaster Certificate but wants more confidence/experience in all conditions. Wants to achieve the skills to take out her boat singlehanded one day. Both of us are keen to learn all the great spots to go to in the local area and perhaps learn to fish! Happy to meet fellow boaties in the area and share day trips out on the water. Would love to do a bit of crewing on a yacht in exchange for the experience and happy to take someone out on the Sea Ray to a great anchorage/fishing spot in exchange for the support/learning.

Richard Brown has had a life time of sailing. Sailmaker AYBA secretary YNZ director of programmes, International Race Officer (now National) extensive Race Management, current GHYC protest panel chairman propose to stand for Sailing Committee. Owner of Madrigal Townson 32 marina K73

September Mystery anchorage. Where is Zuben at anchor?

CLUB HAPPENINGS

After a great July with well attended functions, we can forget about August with the lockdown and celebrate being open again in September, so it was fantastic that some 50 people joined us for dinner last Friday.

At the current Covid Level 2.5 we can still hold our planned Quiz Night & photo judging competition on Friday 18th and the AGM on Wednesday 23rd, with people seated in groups of no more than 10. We are also thinking positive and have pencilled in a Club Spring Clean Day for Tuesday 29 September.

As people Spring clean at home and on the boat, here's an opportunity to get rid of some of your old 'clutter' at the annual Boat Bits Bring 'n' Buy Sale, being held on Sunday 4 October in conjunction with an All Sorts Car Boot Sale.

Community Corner

We have all heard of the '3Rs' Reduce, Reuse, Recycle and the Club will now start collecting plastic bread bag tags to be recycled, adding to the wine bottle tops collection that has been running for some time. Bring these items along, hand in at the bar, reduce landfill and support local charity fundraising efforts.

If you love the marine life around our coast, have a look at the work of LegaSea https://legasea.co.nz/ and the movement to restore our coastal fisheries.

Mike's young crew

ON THE WATER

The fourth & final race of the You Travel Winter Cruising Series was contested on Saturday 5 September. On a lovely Spring morning eight boats set out on the 15.6Nm Course, taking them around the GH Yellow Buoy, North & South Long Bay Marine Reserve marks and out to Navy buoy. Share Delight hosted two of our Youth Sailors who proved to be fast learners under the guidance of Mike & Sheryl and the race provided a good range of learning opportunities.

Series results: 1st Memphis, 2nd Shine On, 3rd Share Delight

There are just two races remaining in the Hibiscus Marine Coatings Winter Series, with the results and Series Prizegiving at GHYC after the final race on Sunday 27 September.

Our Wandering Poles

By Michael Pignéguy

Just north of Baffin Island with a latitude of 74°30" North while transiting the eastern section of the North West Passage, I was checking the chart that was being used and it noted that 'magnetic compasses are not reliable in these latitudes northwards'. This was because the angle of dip of the lines of the earth's magnetic field would force the compass card too far from the horizontal for the card to be effective. With an angle of dip in excess of 80° that was to be expected! The maximum angle of dip of 90° is at the actual pole, with the minimum of zero degrees at the magnetic equator. Luckily the year was 1999 and the ship, being Image: Wikipedia

an ex-Russian spy-ship, was well equipped with modern navigation systems.

Compass cards are compensated so that they can be used in higher latitudes, with most made with a dome in the middle, on the underside of which is where the vertical pin fits into a jewelled bearing that allows the card to swing freely and able to dip to around 15°to 18° out of the horizontal plane. At that time the North magnetic pole was approximately 450 nautical miles to the NNW of us, but since then it has moved around another 600 nautical miles to the NNW. So how did that happen?

Early days

It initially appeared to early European navigators that it was the Pole Star or some mysterious magnetic island in the far north, that was the attraction for their compass needles to point in that direction. But it was not until 1600 that the English physician William Gilbert proposed that the Earth itself acted like a giant magnet. Gilbert then went on to define the North Magnetic Pole as where the Earth's magnetic field points vertically downwards.

Over 200 years were to pass before the British Royal Navy Officer James Clark Ross, established in 1831 the position of the North Magnetic Pole to be at Cape Adelaide (70°04' N, 96°37'W) on the Boothia Peninsula, just west of Baffin Island. Many expeditions were to follow with the explorers establishing different positions for the North Magnetic Pole, making it obvious that it was not a stationary point, but one that was continuously on the move. Between 2009 and 2019, the North Magnetic Pole was plotted at moving towards Siberia at a speed of 55 to 60 kms per year. Not exactly in a rush, but it is of some significance and still a mystery in scientific circles.

Earth's Inner Core

Even Einstein couldn't figure it out and said it was one of the great unsolved problems in physics. Sir Joseph Larmor (1857-1942) was a theoretical physicist, and in the early 1900's suggested that the Earth's magnetic field was the result of a rolling, electrically conductive liquid at the Earth's centre, acting as a geodynamo. It's now known that the Earth's core is made of metal, but in two parts. The inner core's temperature is a scorching 6,000°C, but it remains a solid because of the immense pressure on it. However, the difference in temperature between the inner and outer parts of the core means that the liquid metal of the outer core constantly flows around in convection currents. The liquid metal is crammed full of electrons and it is this moving flow of electric charges generates a magnetic field.

The direction and speed that this extremely hot liquid metal takes are very complex due to its various viscosities and densities, the effect from the planet's own rotation, the distance from the inner core and its very turbulent flow. This creates a real tangle of magnetic field lines, and it might seem surprising that the North Magnetic Pole isn't moving around a whole lot more than it actually is. But in our eyes it looks like very slow motion, and Gary Glatzmaier of the University of California in Santa Cruz says, "When we say the flow is turbulent, we mean on a timescale of tens of thousands of years".

The Magnetic Field and solar winds

In addition to the large general north-westward movement of the North Magnetic Pole , there is also a daily or diurnal variation in which this pole describes a rough ellipse, with a maximum deviation of 50nm (80km) from its mean position. Charged particles from the Sun bombard the Earth's magnetic field creating disturbances that cause this deviation.

Logic suggests that if the movement of both magnetic poles continues there is the possibility that the poles could eventually change places. This would create all sorts of problems, one of which would be how the magnetic field would continue to deflect away charged particles in the solar wind as it does currently.

To see into the future one sometimes has to look into the past, and the history of the Earth's magnetic field shows that is has both strengthened and weakened, even flipping entirely. In fact, over the past 83 million years there have been 183 pole reversals, the last one being 780,000 years ago.

Solar wind, which is blasted from the Sun at terrifying speeds of up to 800 kms/second, comes to Earth full of a mix of protons, electrons and ions, and hot enough to bake us into extinction. But thankfully we have the Earth's magnetic field that protects us from being cooked, although occasionally a solar storm will penetrate the magnetic field enough to cause disruption to our communication and electrical systems.

How the Earth's magnetic field protects the planet from solar radiation

Meanwhile, down South

The Earth's magnetic field is not exactly symmetrical, and the North and South Magnetic Poles are not antipodal, with the South Magnetic Pole not being nearly as mobile as its northern partner. It actually lies outside the Antarctic Circle and is moving northwest approximately 10 to 15 kms per year.

Movement of the South Magnetic Pole: 2020 position 64.073°S, 135.87°E.

Geomagnetic and Magnetic Poles

The Earth's magnetic field is very similar to that of a bar magnet, also called a dipole, and this is tilted at about 9.6° to the Earth's rotational axis which defines the Earth's geographic North and South Poles. As this is a constant (more or less), unlike the actual magnetic poles, the geomagnetic poles have positions of equal degrees of latitude and supplementary degrees of longitude respectively. In 2017 the positions were: Lat 80.50°N and S, Long 72.80°W, 107.20°E

Of course, if the Earth's magnetic field were a perfect dipole, then the lines of magnetic force would be vertical at the Geomagnetic Poles and not wandering around with their respective Magnetic Poles instead.

Changes in magnetic declination

We commonly refer to magnetic declination as magnetic variation which we apply to our magnetic compass bearings to obtain a true reading. Magnetic variation in Auckland just now is 19°55'E. Because of the wandering magnetic poles this local variation has an annual rate of change of 1'E per year. As we would normally use magnetic variation by rounding off to the nearest degree, this annual rate of change is no big deal, unless you happen to be using an old chart. But then, who uses charts these days for navigational purposes?

With the increasing speed at which the North Magnetic Pole is moving , and thus changing the pattern of the lines of the Earth's magnetic field faster than has been the norm, it is becoming more difficult to predict what the magnetic field will be at any point in the future. The World Magnetic Model for the years 2020 to 2025 was made available in December 2019 by the National Centers for Environmental Information (NCEI) and the British Geological Survey. A new International Geomagnetic Reference Field is adopted every five years, and these have previously been based on the rate of change over several years preceding the model generation. Since the rate of change now appears to be increasing, any models created beyond five years are likely to have in-built errors.

The Earth's Magnetic Field and GPS

The World Magnetic Model is built into consumer electronic devices that have in-built digital compasses, including GPS units. This alone gives our GPS the ability to give magnetic bearings or courses when required , but this is calculated from the in-built World Magnetic Model by adding or subtracting the Earth's calculated variation at your location from True bearings as supplied from the GPS.

Of course, if your electronic navigational aids shut down, for whatever reason, knowing what the magnetic variation is in your location suddenly becomes very important. Time to get your charts out!

Mystery Photo Answer: Rarohara Bay, Port FitzRoy (just off the wharf)

Last updated 04:42 on 14 November 2020

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