Last fall I took an Island Packet 44 from Clear Lake down to the island of Grand Cayman which is in the Caribbean to the south of Cuba. The trip is memorable for a number of reasons, not least that it was the fastest Gulf of Mexico crossing that I have made. We left on Monday December the 1st on the tail end of a cold front and with another, fairly weak front still heading south over the central states. That second front caught up with us on Tuesday night and stayed with us well into the Caribbean Sea giving us fast sailing on a reach nearly all the way.
Before leaving Clear Lake, I had planned to head south east towards the Yucatan Channel and, once there, stay in the shallow waters on the west side to avoid the strong currents as we headed south through the channel. But with a north wind still blowing I revised this decision as we approached the Yucatan Peninsular on Thursday evening. The shallow waters on the Mexico side could be rough in a north wind and the center of the channel definitely had to be avoided as the strong north bound currents meeting the north wind would make this a dangerous place for even large boats. Thus I made the decision to head east towards Cuba and to pass through the Yucatan Channel on the west side close to Cabo San Antonio. There, the water remained deep and the Sailing Directions promised a weak or non-existent current close inshore.
The decision was correct, but it left me with a navigational problem. The sailing directions informed me that there was a Traffic Separation Scheme in operation off Cabo San Antonio yet it gave no location for the lanes. And my detailed chart of the Yucatan Channel (DMA #27120) also failed to show the lanes. Whether this is political or not I do not know, but it left me with a difficult decision: how to pass through this area safely and in accordance with the International Rules.
With no information about the location of these lanes I used my judgement to estimate where I thought they would be and acted upon this. And though we did see a lot of shipping and had to use our radar all of Saturday night, we managed to negotiate the area safely and by Sunday morning we were sailing in the turquoise waters of the Caribbean sea.
I learned about Traffic Separation Schemes in England where they are used in the English Channel and North Sea. In these areas there is an incredible quantity of shipping and without the separation schemes many more shipping accidents would occur. In fact they are so essential that even skippers of recreational boats crossing the channel to France have received heavy fines for failing to comply with the rules.
Here in Texas we have our own separation scheme in operation at the entrance to Galveston, and with trips to Cuba becoming more common it seems time that I discuss the rules for these schemes here.
Rules governing Traffic Separation Schemes
Traffic Separation Schemes are essentially divided highways for shipping. They control the movement of vessels in congested areas by regulating opposing flows. The specific rules for these schemes are contained in Rule 10 of the International Navigation Rules (Rule 10 of the Inland Rules is identical). However, Rule 10 begins by stating that the rules that follow only apply to Traffic Separation Schemes adopted by the International Maritime Organization (IMO). The schemes in operation around the coast of Cuba (there are several others besides the scheme operating off Cabo San Antonio) are adopted by the IMO but the scheme at the Entrance to Galveston is not! However, paragraph 161.10 of the Code of Federal Regulations volume 33 ( 33 CFR) states that the operator of a vessel in a Traffic Separation Scheme shall comply with Rule 10 of the International Rules and thus, indirectly, the Galveston scheme is included.
The different zones used in a Traffic Separation Scheme
Traffic Separation Schemes have 3 types of area. There is an area designated as an Inshore Traffic Zone and there are the opposing traffic lanes with a Separation Zone (or Separation Line) between them (see Fig 1).
Inshore Traffic Zones
- Inshore traffic zones may be used by vessels less than 20 meters or sailing vessels. They are also frequently used by fishing vessels when fishing. Large vessels may use an inshore traffic zone when en route to a port, offshore installation or structure, pilot station, or any place situated within the inshore traffic zone, or to avoid immediate danger.
- Lanes are usually at least 3 miles wide and often more than this. The traffic lanes are normally only used by larger vessels. I cannot think of any circumstance when I would choose to use a traffic lane in a small vessel. If you do, remember you are not allowed to impede the safe passage of any vessel following a traffic lane.
Separation Zones (or lines)
- The separation zone is an area like the median of a divided highway that separates the opposing traffic lanes. Small vessels only use the separation lanes when crossing the area though fishing vessels often use this area for fishing.
Most Separation lanes are at least 2 miles wide though where there is not sufficient room to have a wide separation zone it may be reduced to a line.
The main rules to be aware of for small vessels (sailing or less than 20 meters)
The schemes are designed to control the movement of large vessels. Within rule 10 there are special rules that relate to vessels of less than 20 meters (65.6 feet) or to sailing vessels.
Though small vessels may use a Traffic Separation Scheme they shall not impede the safe passage of a power-driven vessel following a traffic lane. In fact vessels of less than 20 meters and sailing vessels are allowed to use the Inshore Traffic Zone when passing through an area.
The main points to comply with if you are in a small vessel are these:
- Whenever possible stay away from the Traffic lanes; use the Inshore Traffic Zone
- Give-way to vessels using the traffic lanes
- If you have to cross the lanes then do so on a heading that is at right angles to the traffic flow
The main rules for large vessels (greater than 20 meters)
- Vessels should normally use the appropriate lanes when passing through an area
- They should normally enter at the beginning of a scheme and leave at the end
- If entering or leaving at any other place they should do so at as small an angle as practical
- They should keep clear of the Traffic Separation Zone or Line
- They should only use the Inshore Traffic Zone when going to some specific place
As with all of the Navigation Rules, International and Inland, they are designed to be readily understood by seamen. They are not like most legal documents: they really are fairly easy to read and to understand. Next time you are on your boat and not going out, find your chart for the entrance to Galveston and look at the Separation Scheme in operation there. And then get out your copy of the Navigation Rules and read through Rule 10.
And finally, if you are planning a trip to Cuba then get hold of the British Admiralty Charts for that area: they do show all the Separation Schemes on the chart!