A run from the Hawaiian Islands (20 degrees north, 155 degrees west) in the Northern Hemisphere to Tahiti in the Southern Hemisphere, (18S/149W) is an experience that will take you south through two trade-wind belts, the doldrums, equatorial currents and counter currents while reaching along in 10 to 15 knots of consistent easterly winds.
Sailing from Hawaii to Tahiti is a natural second leg on a Pacific crossing and provides an opportunity to enter the South Pacific near the eastern end of its extensive island archipelago. An extended sail through the South Pacific islands, which stretch more than 5,000 miles from Tahiti to Palau, can be a challenging quest.
Leaving from Hawaii anytime between April and November will take you out of the hurricane season of the Northern Hemisphers and across the South Pacific waters during the typhoon-free season.
Because Hawaii is located at the southern edge of the mid-latitudes, getting some of the trailing edges of low pressure systems, you can usually expect easterly winds. Initially, they will be northeast then, just north of the equator, will shift to the east. They will settle into a southeast direction as Tahiti is neared. Although doldrums can be expected at around 8 degrees north, they are rarely more than 120 to 180 miles in width. Historically, calms occur only one percent of the time along the rhumb line between Hawaii and Tahiti.
Local thunderstorms and low pressure troughs can bring westerly winds, but they usually don't last long before the trades set in again. Palmyra Atoll (6N/162W), for example, sits in the convergence area of the northeast and southeast trade winds and, though not typically shown on weather fax charts, can experience westerlies, and can have unsettled weather. Squalls with west winds reaching 25 to 30 knots are not uncommon.
One concern in these waters are equatorial currents, which often flow at several knots, especially near clusters of islands, such as the Line Islands (2N/157W). Close to these islands, currents of 2 to 3 knots have been reported. Teraina Island, 120 miles southeast of Palmyra Atoll, and on the south edge of the equatorial countercurrent, can have wide ranging currents which can make accurate position-fixing difficult. Detailed information on currents can be found in Defense Mapping Agency publication 122, "Sailing Directions (Planning Guide) for South Pacific Ocean", and publication 126, "Sailing Directions Enroute - Pacific Islands". This information, along with Jimmy Cornell's "World Cruising Routes and Ocean Passages for the World", are excellent references.
Equatorial current strength and direction changes quickly where west flowing equatorial current and east flowing counter currents meet. This meeting is often obvious, seen as changes in water clarity and temperature, but, just as often, there are no visible indications.
Additionally, near atolls and island chains, where water flow is constricted or funneled, currents often increase. Some atolls experience a continuous outflow of water through their passes and can reach speeds of 3 to 5 knots when trade winds add on. A continuous outflow usually occurs between June and September when the trade winds are the strongest and currents can reaching up to 12 knots.
Another concern of a completely different nature is fishing vessels. Commercial fishing vessels are abundant in the Pacific, and when actively engaged in fishing, their lines can stretch 15 miles or more at depths from 35 to 75 feet. Floats, every 200 to 400 yards, are attached, and vessels can normally transit over them safely, but caution is advised.
Fish havens exist, often marked by orange lighted buoys with radar reflectors, exist near many atolls. Because these havens often consist of shallow artificial reefs designed to attract fish, sailing directions recommend keeping a minimum of 300 feet from these marks. FADS are floating contraptions of various shapes and forms which are moored in deep water and designed to attract fish. They can be encountered from Hawaii to French Polynesia. Fishing vessels are normally found in their vicinity and it is not uncommon for a FAD to break loose and drift off.
Keeping you free of hazards are the three types of buoyage systems used to mark channels in South Pacific: IALA system B (red to starboard), IALA system A (red to port), and a special system to mark minor channels inside barrier reefs where channel direction may not be obvious. The red-to-port system is used within French Polynesia, which includes Tahiti.
The special system, red is used to mark the land side of channels and green is used to mark the reef side. Marks and buoys, however, are not always accurately charted and often in poor condition so cannot be relied upon.
Of greater concern than buoys, fishing vessels and FADS are the French atolls near Tuamotu (20S/140W) which are used for nuclear testing and restricted to entry.
It is also worth mentioning that Tofua Island (20S/175W) is an active volcano that erupts for 5 minutes every 10 minutes with smoke and flames visible and clearly visible day and night.
Though stops can be made at Palmyra island or the Line Islands on the way to Tahiti, these stopovers require more effort than you might want to expend, especially when wind and current make approaches difficult. Often it is best to continue directly to Tahiti, where sheltered and protected anchorages are more easily entered.
Tahiti lies 2,270 miles south-southeast from Hawaii and presents such a lush and paradise-like appearance that it is no wonder British sailors were reluctant to return to cold and gray England after experiencing this tropical haven. During Spring months winds between Hawaii and Tahiti average Beaufort Force 4 (11-16 knots) with no gales recorded. Water temperature is 80 degrees and wave height averages 5 feet.
A boat averaging 7 knots can complete the passage in in approximately 14 days. A rhumb-line course to Tahiti from Hawaii requires a heading of 170degree true and with winds easterly and southeasterly for most of the passage, thus a port-tack reach. Ocean Passages for the World recommends initially heading east and then south when departing Hawaii to ensure an off-the-wind sail. Caution is advised when making landfall and approaching or passing atolls and islands as charted positions of many land masses have been noted to be off as much as 2 miles. These discrepancies have been noted mostly because of the accuracy afforded by GPS.
Tahiti is 33 miles long, 15 miles wide and consists of two mountain ranges with peaks that rise to heights of 4,000 and 6,000 feet. These mountains are often shrouded in rain clouds and not visible. A reef surrounds the Island at a distance between 1 and 2 miles and provides several protected harbors.
Trade winds blow from the southeast between May and September and northeast to northwest from January to April. Altered by Tahiti's mountains, the shore winds can be east-northeast to east-southeast. Currents from l to 3 knots set along Tahiti's coasts, to the northwest on the north coast and to the southeast along the south coast. Tahiti and can be contacted on VHF channel 10 and SSB frequency 15650 MHz.
The greatest weather concern in the South Pacific is the typhoon season, which runs from November to April. Many typhoons appear to originate near the Samoa Islands (14S/170W) and the Line Islands (2S/157W). A US Coast Guard (NPN) and US Navy communication station (NRV) are located in Guam and both broadcast weather warnings, charts and messages. Channels and frequencies monitored include; 4B (4143.6 kHz), 8A (8291.1 kHz), 12B (12432.3 kHz), and 2182 Khz. Additionally, weather broadcasts are made from Hawaii and New Zealand.
Several weather facsimile charts are particularly useful in locating trade winds, tropical waves, disturbances and currents. The East Pacific Surface Analysis, produced by the Tropical Prediction Center at the National Hurricane Center in Miami, shows air flows and significant cloud formations and cloud type. Details on this chart can be obtained by calling the Hurricane Center at (305) 229-4470.
New Zealand's Met Service in Wellington broadcasts a significant weather (SIGWX) prognosis chart covering an area from 50 degrees north to 50 degrees south and from 120 degrees west to 170 degrees east. It depicts cloud structure and type and upper-air winds. In addition the National Weather Services Marine Prediction Center produces charts depicting Pacific surface, wind/wave and upper-air conditions every 6 hours.
If this route is sailed in reverse, from Tahiti to Hawaii, a few modifications are in order. A more easterly heading is recommended than was used coming south. Once the doldrums are crossed, winds will be mostly from the northeast, making Hawaii an upwind destination if easting has not been accomplished.
To avoid Southern Hemisphere typhoons and have the best winds on both sides of the equator, the best time of year for making a northward passage is April to July, To get sufficient easting, several cruising guides recommend crossing the equator between 145 and 147 degrees west after first sailing to 15S/149 west.
Either way, sailing north or south and using Hawaii and Tahiti as destinations will take a voyager across many miles of beautiful Pacific waters and provide a warm and fascinating blue-water trip.
Last edited by Jeff_H; 01-12-2011 at 08:44 AM.
|Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)|