Archive for the ‘Navigation and Passage Planning’ Category

« Older Entries

Going aground

Monday, July 5th, 2010

When I read that a yacht ran aground on shallow reefs because of lower than usual tides, I was perplexed. But perhaps that’s because I haven’t been sailing around Bermuda recently.

Meteorologists with the Bermuda Weather Service have reported that tides have been lower than expected due to the effect of cold eddies circling the island. Tides have been recorded to be 0.7 ft to one foot lower than average.

A prudent skipper would not be caught out. He would know what his yacht draws and allow a much greater amount of water between it and the sea bottom.

Fortunately for the skipper involved, nearby motor boats were able to rescue the yacht from the reef and only minor damage occurred.

Tags: , ,
Posted in Navigation and Passage Planning, Safety and Emergencies, Weathercraft | Comments Off

Full Report on the Flinders Islet Yacht Race, 9 October 2009

Friday, February 26th, 2010

The 86-page Internal Report prepared for the Cruising Yacht Club of Australia (CYCA) has been released publicly. Its authors, Rear Admiral Chris Oxenbould AO RAN (Rtd), Past Commodore David Kellett AM and Past Commodore John Brooks reviewed reports from and interviewed surviving crew from PWC Shockwave, skippers and crew from yachts involved in the search and rescue (SAR) as well as CYCA staff and race management volunteers.

Interviews were also held with the hydrographer of Australia, members of the Marine Area Command of the NSW Police and staff from Australian Maritime Safety Authority who were involved in the SAR. Information on the reliability of GPS systems was provided by a representative of Garmin Australia.

In addition to investigating the PWC Shockwave incident, the Inquiry Committee interviewed and reported on the recovery of the man overboard from Patrice VI and communications difficulties experienced by crew of that yacht.

There is lots of information in the report that is relevant to all who sail offshore anywhere in the world, whether cruising or racing.

I recommend you download and read the findings of the Flinders Islet Yacht Race Inquiry, in particular the recommendations on pages 55-59. Your life may depend on it.

Tags: , , , ,
Posted in Navigation and Passage Planning, Safety and Emergencies, Skipper and Crew, Knots and Ropework | Comments Off

20% off The Boating Bible Manual of Seamanship

Tuesday, December 1st, 2009

During December 2009 you can purchase The Boating Bible Manual of Seamanship for only AU$156 – a 20% discount off its advertised price. This multimedia Manual contains the five titles listed below, plus you receive a free bonus 75-minute DVD, The Joys of Sailing.

If you’d prefer, you can buy single CDs for AU$40.50 – 10% off the advertised price. These would make ideal Christmas gifts for your family or friends who share your love of sailing:
* Boat Handling 1 and 2 (not sold separately)
* Navigation and Passage Planning
* Safety and Emergencies
* Skipper and Crew, Knots and The Language of the Sea
* Weathercraft

Order The Boating Bible Manual of Seamanship now to ensure you receive in time for Christmas.

Take advantage of this special offer today before prices go back up!

Tags: , , ,
Posted in Boat Handling, Navigation and Passage Planning, Safety and Emergencies, Skipper and Crew, Knots and Ropework, The Language of the Sea, Weathercraft | Comments Off

The ABC of Scend = D

Friday, October 23rd, 2009

First, for those people who don’t know what scend is, here is a definition:

Scend is the distance from sea level to the bottom of the trough of a wave. The trough can be taken as being equal to the height of the wave above sea level, or more simply as half the height of the wave. This means that, with a 3m sea running over a bar, the depth available to you may be 1.5m less than you would have in a flat sea.

So how does a navigator deal with it? You need to think of the charted level of the sea, the average height of the waves and swells combined. To this you add your calculation of the relevant state of tide and estimate the scend with the above definition in mind. Call that ‘A’.

‘B’ is the depth of the keel and the amount of scend. Subtract ‘B’ from ‘A’ to get ‘C’. If ‘C’ is negative there isn’t enough water. Even if it is positive there has to be a reasonable safety margin.

Then, depending how frightened you are, add a second safety margin. Call that ‘D’.

Tags:
Posted in Navigation and Passage Planning, The Language of the Sea | Comments Off

Offshore wind farms – another sailing hazard?

Tuesday, October 20th, 2009

If, like me, you’ve sailed through areas where oil rigs are located, you will know that they are easy to see, both during the day and at night. In fact, overnight they are lit up like well-decorated Christmas trees. Navigating to avoid them is, therefore, not difficult except perhaps when there’s fog.

But, after reading about a new wind farm development, I’ve been wondering what it would be like sailing through or near one, if that’s permitted.

The world’s largest offshore wind farm will be built in the UK off the Kent and Essex coasts. Located 12 miles offshore, it will be out of sight of land.

There will be 341 wind turbines generating 1,000 megawatts of electricity – enough to power all 750,000 homes in Kent and East Sussex and save 1.9million tonnes of carbon dioxide per annum.

Read the full article on this wind farm.

Tags: ,
Posted in Grab Bag or Miscellany, Navigation and Passage Planning | Comments Off

Know your nautical buoyage – IALA Regions A and B

Friday, September 25th, 2009

Some years ago, approaching the finish of the Melbourne-Osaka double-handed yacht race, one boat came to grief. The crew, probably excited about completing the 5,500 mile race, forgot that Japan is located in IALA Region B. So, instead of steering their yacht through safe water, they ran it aground. Ouch! And after all that effort.

To save you from suffering a similar fate, we’ve developed Buoyage – IALA Regions A and B. As well as listing the countries under their region, there’s a section where you can learn or revise the cardinal, lateral and all the other buoys – their shapes, colours and the lights they display at night.

When you’re ready, you can take an interactive quiz to check your recognition of all the buoys.

Buoyage – IALA Regions A and B is just one of five quizzes we’ve developed in the Nautical Knowledge. The other subjects are:

  • Rules of the Road
  • Navigation Lights
  • Signal Flags
  • Fog and other Sound Signals

The Nautical Knowledge is available as a download for only AU$9.95.

Tags: , , ,
Posted in Nautical Knowledge, Navigation and Passage Planning | Comments Off

Great Australian Bight

Friday, August 7th, 2009

My post about the Round Australia Race and Rally reminded me about my own voyage across the Great Australian Bight some years ago.

Cliffs along the Great Australian Bight

This photo was taken on our way across the Nullabor Plain to Perth. I’m glad to say that our delivery trip, which included a stop-over in Esperance to replace a lost mast, kept us well clear of these terrifying cliffs. There is no break in them for hundreds of miles.

I must restate my admiration for the skill and courage of Captain Matthew Flinders, who charted this coastline in 1802.

Tags: , ,
Posted in Grab Bag or Miscellany, Navigation and Passage Planning | Comments Off

The very best navigation fix of all

Friday, May 15th, 2009

Now that the northern summer is coming so is the sailing. But by no means all of it will be done at sea or along the coast. Many countries have large systems of internal lakes, canals, rivers and other linked waterways where people love to explore and enjoy themselves.

 

In many cases, it’s near where they live and they know the waters very well. But many people are visitors, sometimes from overseas, and they have to know where they are so they can be sure they’re safe.

 

So what’s the best and most helpful bit of knowledge for such people? I believe it is to properly understand what a transit is. It is any two objects of any kind which are on the chart and can be seen in line from the water. Nobody has to know how to apply variation or deviation or any of the other subtleties of navigation because when you are along that transit line the only thing you don’t know is how far along it, but you know without fail that you are on it.

 

So it follows that if you’re able to get two transits – preferably at the same time, but close in time will do at a pinch – and they intersect you are at that point precisely where they intersect.

 

And the great thing about transits is that somebody else can take them while you’re busy steering the boat.

We have a disk which will help you to learn more about navigation and passage planning.

Tags: , , , , ,
Posted in Navigation and Passage Planning | 1 Comment »

« Older Entries