Use the Cruising Guide
Consult the cruising guide before entering any harbor with which you are not absolutely familiar. The cruising guide describes every harbor, explaining how to approach and pointing out all the hazards. It also provides handy diagrams with GPS coordinates and suggested routes. In addition to vital navigational information, the cruising guide also gives a wealth of information about services, businesses, points of interest, attractions, and background information for the area. Cruising guides as well as nautical charts for bareboat cruising areas are available from charter companies and most retail boating stores.

Become Familiar with Navigation Aids
Become familiar with the navigation aid marking system(s) for your chartering location. Charts and cruising guides are available to charterers at home so there's time to get familiar with the sailing area. There are two world lateral systems and one cardinal system in use:

Lateral System "B" is used in North and South American and the Caribbean. It's the "red-right-returning" system we are familiar with here. The red triangles mark the right hand side of the channel and the green squares mark the left hand side of the channel when returning from the sea. Lateral System "A" is used in Europe, Africa, Asia and the South Pacific. In this system the red buoys mark the left hand side of the channel when returning from the sea. The Cardinal System is used to identify whether the mark lies north, east, south, or west of a given obstacle. Two cones, one above the other, apex upward indicates the mark is north of an obstacle. Two cones, one above the other, apex downward indicates the mark is south of an obstacle. Two cones, one above the other, apex to apex indicates a mark to the west and two cones base to base indicates it is to the east of an obstacle. (for pictures see our website)

These marks lie just north, south, east, or west of an obstacle so stay north of the north marker, south of the south marker, etc.

Other systems encountered in bareboating include the system used in French Polynesia to mark the channels between the barrier reef and each central island. In the lagoon, these marks identify the island side of channel with red squares and the outer reef side of the channel with green triangles.

Bring a Handheld GPS
Different brands and models of GPS have different user interfaces so mastery of one doesn't mean mastery of all. Good portable and handheld models are inexpensive enough that any charterer can purchase one before a bareboat charter trip. This will allow time to learn the functions and install user waypoints in the particular unit. Be sure to become familiar with the "GO TO" function. This will tell you the direction to the selected waypoint as well as the direction your boat is tracking. It will also give you course deviation which is how far (and in which direction) your boat has moved from the selected course line. Course deviation is especially valuable when following a course with obstacles on either side. Additionally, the "GO TO" function will tell you how fast you are going and how long it will take to get to your selected waypoint or destination.

This last feature is extremely important. Many anchorages have coral reefs and other obstacles nearby that must be transited in close proximity. Navigation in these areas is done visually by looking through the shallow water to avoid obstacles. This is easy during the mid-day hours when the sun is high enough to allow you to see the bottom. But after about 4:00 p.m. you can't see through even shallow water due to the low sun angle. This makes it virtually impossible to see what you're about to run over. Many accidents have happened because of ill-timed (i.e. late) arrival in areas where it was necessary to navigate visually through shallow water to get to the anchorage.

For more information please visit our website at http://www.spinnakersailing.com. For this article in its entirety including links and photos go to: http://www.spinnakersailing.com/noframes/charters/navtips.

Bob Diamond has been head sailing instructor at Spinnaker Sailing and has been leading group sailing vacations in exotic locations since 1984.