Saturday, February 11, 2017

Here We Go Again

The Gulf Stream is one of the world's strongest ocean currents, and it is strongest just off the coast of southern Florida. Therefore, any crossing from Florida to the Bahamas or vice-versa must take it thoroughly into account, on several different levels. First and most obviously, there is the drift to consider. The Stream flows northward at up to 4-5 knots, but over the course of a crossing one can count on an average of 2.5 knots northward set. This is not inconsiderable against an under-power speed of 5.5 knots, as we do on Windbird. It will take us roughly ten hours to cross 52 miles to the Great Bahamas Bank, during which time we can count on being set northward a good 25 miles! Our rhumb line is 86 degrees magnetic from Port Everglades Inlet to Great Isaac light, 109 degrees corrected for drift, but it would be foolishness to try and maintain it. Instead we will follow an S curve: make greater southing at the beginning, come down to cross the stream at a right angle as quickly as we can once we're into the strongest part of it, and then regain some southing once we're on the east side of it.

The other big consideration is the wind and waves that the Gulf Stream can generate. The water is several degrees above surrounding waters which tends to add energy to the atmosphere; the wind in the Gulf Stream will often gust 5-10 knots higher than outside it. Furthermore, any wind at all with a northerly component against that mighty current will result in big, steep, bruising seas. So to cross the Gulf Stream in the wintertime, you have to avoid 1) the prevailing northeasterly trades 2) the periodic cold fronts that interrupt them. At times you can wait weeks for a good window; that happened last year. This year, thus far they've come with some regularity. The best scenario often involves a weak, stalling cold front that brings a few days of reduced flow clocking from east through southwest. And that's exactly what we have on tomorrow and Monday.

My brother Steve flew in this morning; he was delayed a bit by a faulty starter motor on one of my airline's A320s. Oh well.  We took Piper to the vet and he has a clean bill of health as the Bahamas requires. Great! We took one last run to Southport Raw Bar and the Winn-Dixie behind it, and I got in some paddleboarding on our new SUP when we got back...I even got Piper to ride calmly on the bard! This evening we hosted two of Steve's Miami friends for a nice dinner of salad & kebobs and then we talked in the cockpit fairly late. We have a number of things to do when we get up, but the passage planning is at least done.

I mentioned to Steve that I have butterflies in my stomach for this crossing, which I really haven't had for any other passage thus far. Maybe some of it is crossing the Gulf Stream for the first time, but I think it's mostly just excitement that we're crossing over to the Bahamas at long last. I'm really excited. Just one final morning of work to buckle down on, and then we'll be out Port Everglades Inlet around 10:30am tomorrow!

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