Friday, July 26, 2013

NAVIGATION-Inside Passage part 7

When Captain George Vancouver and his two ships, the Discovery and the Chatham set out to map the coast of British Columbia in 1793, his method of exploration was very simple though backbreaking.

The big ships anchored in strategic places and smaller boats were sent to search the bays and channels.

Several times the big ships ended up in the rocks and frequently the boat trips were of many days duration in very bad weather. Occasionally the crews rowed day and night and on more than one occasion, after a brush with the Indians, rowed for their lives.

Their methods of navigation included a compass and a marine chronometer: a clock accurate enough to be used to determine longitude by the position of stars and the sun.  The maps they produced were valuable references for those who followed.

During our little excursion up into Desolation Sound, Captain Jeffrey had many navigation tools available.

He used a library of maps he kept where they could be referenced… an overhead display in the pilot house.  He was also in constant radio contact with water craft around him and the marine officials on the shore.

 He used electronic aids such as the global navigation satellite systems to find his way around shallow water, hidden rocks and narrow channels.

Captain Jeffrey explained the knowledge of the tides is especially important when navigating between Vancouver Island and mainland British Columbia.

 Big tides from the Pacific Ocean ebb and flow around both sides of the huge land mass causing dramatic turbulence, also know as tidal rapids, as the water forces its way through the narrow passages.  To pass safely, a boater needs to know when slack tide happens.  This is a pause between flood and ebb tide---sort of like the moment between breathing in and breathing out. This break only lasts a few minutes so timing is essential.

Jeffrey was so good at arriving at slack tide that we seldom witnessed the turbulence and strong whirlpools which can swamp a small boat.

 When we arrived at a place such as Dodd Narrows, often there were boats lined up waiting for the moment of quiet between the ebb and flow.

A tangled anchor chain put us a little late at Surge Narrows.  Before we were out into open water we could see huge swirls and whirlpools forming as the water began to churn.

Even though we could see the disturbances caused by the surge of water, our captain skillfully guided our craft around the hazards.  I was almost disappointed we missed out on any kind of adventure.

My video of Captain Jeffrey at the wheel in the pilot house of the David B.


fishducky said...

I'm continuing to enjoy your trip VERY much!!

TALON said...

Amazing how brave the ancient mariners were...can you imagine catching your first glimpse of an unknown land? Awesome photos and story, Leenie. As always, a pure delight to drop in here. Especially on a rainy Saturday afternoon and a fresh cup of tea at hand. :)

Anonymous said...

Great post! Talented man with special skills that must be a joy to see put into practice. I'm glad you made the video so we could see valued learning and experience in action. You were definitely in safe hands there!

RURAL said...

Wow, that would have been very exciting if you got caught in one of those a bad way most certainly.

Great shots, and I too am enjoying the trip.


Val said...

Tidal rapids? Who knew? Not me, that's for sure. I'm a confirmed landlubber. No seagoing for me. The only time I came close was a trip on a ferry from Ketchikan to Juneau. Since I could see land the whole time, it didn't count as the ocean. In my mind, anyway.

Anzu said...

Leenie, you are a talented photographer as a sort of documentary film.
('∇^d) wonderful!