Friday, November 11, 2011

Detailed Passage Information

     I have tried to capture a high level view of the route planning. Note that this is a rough plan. Winds can’t be predicted accurately more than a day or two out, but this is our current thinking. The first chart is the route out of Hampton Virginia. Note the Hampton Roads Bridge Tunnel in the lower right part of the circle. This is the tunnel that we always travel through on the way to Cape Hatteras.

     Our plan is to leave at about 2pm on Friday Nov 11. The Caribbean 1500 is starting at 10 am and the start is off Old Point Comfort (see lower right in chart below). They will have about 70 boats on the start line. The Caribbean 1500 boats all have transponders (like our Spot) and can be followed here http://www.worldcruising.com/carib1500 . I suspect that there will be a variety of different routes chosen. Up until yesterday we were planning to follow the coast south to just off Diamond Shoals / Cape Hatteras to cross the Gulf Stream at its narrowest point. Now we plan a more direct east route to where we believe that we will see better winds in days 3-5. We hate motoring!!


     Here you can see the route out of the Hampton, Norfolk area. Note the Chesapeake Bay Bridge – Tunnel on the right of the chart. This the route that we have taken on our way to Cape Hatteras when we have gone down the Delmarva Peninsula. The bridge-tunnel is almost 20 miles long and has two channels above the tunnels for boats/ships. There is plenty of naval traffic here as Norfolk is the largest naval base in the world and it is full of aircraft carriers, submarines and other warships. On the VHF radio they talk about how they will use “deadly” force if you get closer than 500 yards to a naval ship.  We hope to see some aircraft carriers and submarines on our way out to sea.


     Once offshore the challenge is the Gulf Stream. Opposing wind to the current in the Gulf Stream can build up mountainous seas. According to the wind predictions, once the cold front goes through tonight the winds will back to the northwest and then west. This is the first time that the wind will not be opposing the Gulf Stream in the last week.  Based on our projected departure time of about 2pm on Friday we should be entering the Gulf Stream in the early morning on Saturday with expected 10-15 knot winds from astern.  The Gulf Stream current will be about 4 knots and the water temperatures will rise from 58F where we are presently to 75-78 degrees. The chart below shows the predicted currents and water temps for our Gulf Stream passage. I want to look at a revised Gulf Stream entry about 10 miles south of that shown to pick up the stronger currents to the south. We can’t go too far south though because there is a cold eddy rotating counter clockwise (centred at 34N/73W) that we must stay north of so that we don’t pick up an unfavourable current.


     The predicted sea state and winds when we enter the Gulf Stream look like this.  The dark green shading represents 10-12 foot seas and the brown is 12-14 feet. The largest waves in this sector would be 24-28 feet. Most of this is from of Tropical Storm Sean that is lying SW of Bermuda. By the time we get to this area seas should be down to 5 to 10 feet. The wind will be about 10 knots from the west, it sounds like we might be flying spinnakers at this point.

     Here is the complete route to Jost Van Dyke in the British Virgin Islands. Note that the other way points are those from the southern route that we will not be following. Note that Bermuda is approximately 150 miles east of our planned Day 4 position.


Hopefully in about 9-10 days we will be entering  Jost Van Dyke in the British Virgin Islands.

     The above routing is based on the weatherfax charts below for present , 48 hr and 96 hours. The tropical cyclone activity chart shows that Sean is heading off to the NE after passing Bermuda.

Jon.

3 comments:

  1. Unfortunately, none of the images are visible in the post. Really enjoying the blog though. Enjoy your trip. Safe passage.

    Warren Gallagher

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  2. Have a great sail, guys. It's frosty here in The Bay this morning so can't wait to see some turquoise seas in your BVI photos!

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  3. I see the images just fine in the post...?

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