Crossing the Gulf Stream from Marathon, FL to Bimini, Bahamas

[svcheshirecat]

The best route for us through the Keys between the ICW (Gulf side) and Hawk Channel (Atlantic side) is probably Moser Channel at ICW Mile 1195, just south of Marathon. This is where Seven Mile Bridge is located and it has a 65 foot vertical clearance. Currents run swiftly with either tide. A favorable tide from Gulf to Atlantic would be the ebb tide, which is high tide to low tide. Time your crossing with the high tide to get a tidal assist from the tide from Gulf to Atlantic.

There are many good anchorages around Boot Key. Maybe where Sister Creek comes out to Hawk Channel.
Should fill up with gas and other supplies before doing the crossing because everything is much more expensive in the Bahamas.

Rodriguez Key, an easy day sail from Marathon, is the standard stop to hang out before crossing the stream if you are going to Bimini.

Last year we went straight from Marathon to Bimini. Got there faster than expected doing about 10 knots in the stream.
I agree .....get out in the stream and go along for the ride! You'll be going with the stream pretty much the whole way.
A generalized rule is to go 25 miles or so south of your intended Bahamas destination” in order to cross the Gulf Stream.

Sailing from Marathon, FL to Bimini, Bahamas involves navigating the Gulf Stream, a strong current that can significantly impact your journey. You'll need to factor in the current when planning your route and heading, and consider potential wind conditions. A good strategy is to leave from as far south in the Keys as possible, like Marathon, and aim for a point south of Bimini, allowing the current to help you make your way to the island.

• Departure Point: Choosing a starting point slightly south of your intended arrival point can help you use the Gulf Stream's northward push to your advantage, allowing you to ride the current northward while still aiming east for Bimini.
• Distance and Time: The distance between Marathon and Bimini is approximately 44 nautical miles. The estimated sailing time will vary depending on your boat speed and the Gulf Stream conditions. Some sources estimate a crossing time of roughly 8-11 hours.
• 1. Determine the Straight-Line (Rhumb Line) True Heading:
• Using a nautical chart or chart plotter, find the true heading (in degrees true) from Marathon to Bimini.
• 2. Calculate Your Magnetic Heading:
• Find Magnetic Variation: Determine the magnetic variation for the Marathon/Bimini area using a nautical chart or an online magnetic variation calculator.
• Convert True to Magnetic Heading:
• If the variation is East: Subtract the variation value from your true heading.
• If the variation is West: Add the variation value to your true heading.
• 3. Account for the Gulf Stream:
• The Gulf Stream's Impact: The Gulf Stream will push you north, so you'll need to steer a more southeasterly course to counteract this.
• Let's assume the true heading from Marathon to Bimini is approximately 75 degrees true.
• Let's assume the magnetic variation in the area is 5 degrees west.
• To get the magnetic heading, you would add the variation: 75 degrees true + 5 degrees west variation = 80 degrees magnetic.
• However, due to the Gulf Stream, you'll need to steer more south. You might, for example, steer 90 degrees magnetic or even slightly south of that. The exact heading will depend on your boat speed and the strength of the current.
In summary, to sail from Marathon to Bimini on a sailboat, you'll need to determine your true heading, convert it to a magnetic heading using the local magnetic variation, and then adjust that heading to compensate for the Gulf Stream current, often by steering a more southerly course than the rhumb line.
The average speed of the Gulf Stream between Florida and the Bahamas is typically 2 to 2.5 knots. This translates to approximately 2.3 to 2.9 miles per hour.
However, it's important to note that the Gulf Stream's speed can vary:
• It can be as high as 3-3.5 knots, especially in the center or axis of the current.
• The speed can be as low as 1 knot near the edges of the current.
• It can also fluctuate based on factors like season, weather, and moon phase.
• The Gulf Stream is a dynamic system, and its location and speed can shift.
For navigation purposes, especially when crossing, it's generally recommended to plan for an average current of 2-2.5 knots pushing you north. However, it's best to check current conditions and forecasts for the most accurate information before undertaking a crossing.