The following is from Steve Pavlidis in response to a similar question on the SSCA board. It is copyrighted. May I suggest that those who find this useful, buy is guides for the places theyare going to visit. They are uniformly excellent + he is a generous advisor to the cruising community.
S/V IV Play
Rio Dulce, Guatemala
The following material is Copyright Stephen J. Pavlidis 2006
Heading to the Río Dulce from Florida
This section deals with the passage from Florida to the Río Dulce. On this route we will discuss Quintana Roo, the Yucatán Peninsula of Mexico, and Belize, including the offshore reefs.
For more information on currents pertaining to route planning, see the section Tides And Currents in the chapter, The Basics.
From the Gulf of Mexico
Cruisers that are used to crossing the Gulf Stream from Florida to the Bahamas face a similar scenario when heading to the Yucatán from South Florida and the Keys. Here you will have to cross the Gulf Stream as well as the Yucatán Current, which flows through the Yucatán Channel to become the Loop Current in the Gulf of Mexico and eventually the Gulf Stream.
The Yucatán Channel lies between the mainland of Mexico and the Island of Cuba to the east. It is deep along it’s eastern edge and shallows as it approaches the Mexican coastline. There is a tremendous flow of water passing through the Yucatán Channel into the Gulf of Mexico and the set of the current can surpass 4 knots at its axis. The eastern edge of this current lies about 20 miles off Cabo San Antonio, Cuba, and about 35 miles west of Cabo San Antonio the current strength is about 1 knot (bear in mind that these figures are an average and that may not represent the actual conditions you might find). About 50 miles east of Cabo San Antonio the strength is double, about 2 knots, while approximately 60-70 miles east of Cabo San Antonio the current increases to about 3 knots. Around 75-80 miles east of Cabo San Antonio you’ll usually find the axis where the velocity can exceed 4 knots. Oddly enough, 15 miles further west, about 25 miles from the Yucatán coast the current strength drops to about 1 knot. The current in the Yucatán Channel is stronger in summer and the width of its reach wider, while in the winter the velocity decreases as does the current’s width. Bear in mind that this is not cast in concrete, cruisers have reported both lesser and greater strengths at varying times of the year.
A plot of the main path of the Yucatán Current is prepared by the U.S. Navy and is available from their web site: www.nlmoc.navy.mil/home1.html.
This plot is quite enlightening but it fails to show the numerous eddies and counter currents generated by the current. Such an eddy runs westward close in along both the Florida Keys while another runs along the northwestern shore of Cuba and can be as strong as ½-1 knot. This counter current has been reported as far as 30 miles west of Cabo San Antonio, Cuba. Along the southern shore of Cuba, between Cabo San Antonio and Cabo Cruz (north of Jamaica), you’ll find a westerly setting current of about 1 knot depending on wind strength and direction, and a counter current closer in that sets in a southeasterly direction. At any time you are likely to see a reverse of the primary current flows in the Northwestern Caribbean, especially north of Jamaica, between Jamaica and the Cuban coastline. You’ll also find eddies, counter currents, at almost any point in the Northwestern Caribbean between Jamaica and the Yucatán Channel that will set you in any of several directions depending on which side of them you are. A great way to get a handle on these eddies is to subscribe to Chris Parker’s Caribbean Weather Center and check in daily on the SSB. Chris can tell you where the eddies lie and where you need to go to get on their best side and have them work for you.
Sailing from the Florida Keys to Isla Mujeres there are two primary routes to choose from and which one you choose will depend on the strength of the Yucatán Current and the Gulf Stream. The first route (the choice for those seeking to have the currents work for you) brings you southward across the Gulf Stream and then westward along the northwestern shore of Cuba, about 12-15 miles off, where you can hopefully pick up the westerly setting counter current of ½-1 knot. Soon after you pass the western tip of Cuba you’ll lose that boost as the current dissipates around Cabo San Antonio.
The second route depends on the strength of the Yucatán Current. If the Gulf Stream is in its normal position favoring the Cuban side of the Straits of Florida you can plot a westerly or southwesterly course staying north of the current as you head toward Isla Mujeres. This route becomes difficult when the Yucatán Current is running strong as it passes through the Yucatán Channel making your southwesterly course towards Isla Mujeres hard to maintain even with favorable winds. It’s not unusual for sailors to sail a bit west of the northern tip of the Yucatán Peninsula to get out of the Yucatán Current and then turn back to the southeast for Isla Mujeres even though they had favorable winds when the current pushed them northward at 4 knots.
For information purposes, the distance from Key West to Isla Mujeres is approximately 325 nautical miles on a heading of 235°, while the distance from the Dry Tortugas to Isla Mujeres is approximately 295 nautical miles on a heading of 230°. From Havana to Isla Mujeres the distance is approximately 274 nautical miles, part of it paralleling the northern coast of Cuba.
Tides and Currents
Cruising in the Northwest Caribbean, and in general just getting to the Northwest Caribbean, you will encounter strong currents that, depending on your route, will be either with you or against you.
The currents that you encounter originate 93 million miles from Earth where our Sun generates the heat that warms the lower latitudes of our planet causing the air to expand creating tradewinds that drag the ocean waters with them (thanks in part to the rotation of the Earth and the influence of the Moon). In the Caribbean Sea and the southern part of the North Atlantic Ocean, these currents flow westward at about .7 knot and originate off the western coast of Africa, just north of the Cape Verde Islands as the North Equatorial Current.
South of the equator the South Equatorial Current begins its westward flow with the trades like its cousin to the north. Somewhere off the coast of Brazil the current splits in two with the northern half running northward along the eastern coast of South America (as the North Brazil and Guiana Currents-the Guiana Current enters the Caribbean along the northern shore of South America and is influenced by the flow of the Amazon River and the Río Orinoco) where it joins with the North Equatorial Current. This combined current pushes into the Caribbean basin where the flow divides, the larger Antilles Current heads north through the islands while the second current enters the Caribbean basin through the Grenada, St. Vincent, and St. Lucia Passages and moves northwest in a poorly defined and highly variable stream called the Caribbean Current. In fact, the Caribbean Current begins as several westward flowing streams that are separated by eastward flowing countercurrents (in the extreme southwestern Caribbean a counterclockwise current called the Columbia-Panama Gyre is evident from Nicaragua through Panama and eastward to Columbia). Eventually these westward flowing streams merge as the Caribbean Current and continue west past Jamaica and Cuba and then northward through the Yucatán Channel (where it is called the Yucatán Current) and into the Gulf of Mexico (where it is called the Loop Current). Flowing north the Yucatán Current begins experiencing a certain resistance from the waters already in the Gulf of Mexico and rarely is felt in the western Gulf. Along the main path of the clockwise rotation of the Loop Current in the Gulf of Mexico several eddies break off as the current turns towards the only exit, through the Straits of Florida between Florida and Cuba where it is technically called the Florida Current, though it’s better known as the Gulf Stream, and is joined by the Antilles Current that flows west along Cuba’s northern coast. At some point in the Straits of Florida the powerful Gulf Stream is born. Once past the Bahamas the Gulf Stream joins up again with a part of the Antilles Current that flowed northwest along the eastern edge of the Bahamas and begins its easterly trek across the North Atlantic Ocean to re-circulate and do it all over again.
What this all boils down to is this: if you intend to leave the Florida Keys to cross the Yucatán Channel and work your way south along the eastern coasts of Quintana Roo, Belize, and into the Gulf of Honduras and the Río Dulce, the current will be on the nose, at times up to 4 knots in the middle of the Yucatán Channel, and often 1-2 knots and more along the eastern coast of Quintana Roo, and a bit less in the lee of the Belizean Reef. If you are heading to the Northwest Caribbean from the Windward Passage or Jamaica the current will be on your quarter or beam, and if you’re approaching from the Eastern Caribbean you’ll have the current with you. For more information on how these currents affect your route planning, see the sections Westward to the Río Dulce and Heading to the Río Dulce from Florida.
The tides in the Cayman Islands are primarily diurnal with one high and one low each day, though on some days the tides will be semi-diurnal with two highs and lows per day, and are generally in the range of 1’. The currents in and around the Cayman Islands generally set to the west, though a northward flowing current can be found south of Grand Cayman at times, and a southward and/or eastward flowing current can be found between Cuba and the Cayman Islands at times.
Tides in Jamaica are primarily diurnal, one high and one low each day, and are small, generally about 1 foot or less. There is a westward setting current off both the northern and southern coasts of Jamaica of about .7-1.0 knot with a reported current of up to 2-3 knots two miles off Morant Point. At times, the westward setting current has been reported to reverse its direction, especially during periods of westerly winds.