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September, 2016

Passage Note #86 - Cruising the Tuamotus: The Dangerous Archipelago

 “No distinction is so continually dwelt upon in South Seas talk as that between the “low” and the “high” island, and there is none more broadly marked in nature.  The Himalayas are not more different from the Sahara”......The Tuamotus are like a new province of creation...of a heavenly prettiness.”........................................Robert Louis Stevenson  (1888)

We found ourselves in an immensely different world when we left the Marquesas Islands on May 21 -- by sailing just 500 nautical miles to the southwest, we suddenly entered a new universe that was at times eerie and unreal, perilous and otherworldly......but always always incredibly stunning.  The "heavenly" Tuamotus are an exotic South Pacific postcard - one of the idyllic visions you have of Paradise in your dreams.   They are sparsely inhabited, a quiet and remote corner of the world.   But we also couldn’t forget - they were known in sailing history as the “Dangerous Archipelago” for good reasons that continue today. 

Back on Tahuata Island in the Marquesas, we waited.  And waited. And waited.....impatiently ready to leave, checking the gribs and all our weather sources.  We were stalled here a few weeks for lack of wind and on the other end, at our destination, the weather had been unsettled and squally.  We were finally able to identify a favorable window from our meteorological overlords and took off, sailing for 4 days, from Hanamoenoa Bay where we made landfall in the Marquesas nearly one year ago, to Raroia, our first atoll in the Tuamotu Islands.

What an abrupt contrast!  We had traded the towering green volcanic mountains, rugged rocky sea cliffs, waterfalls, rolly anchorages and abundantly growing fresh fruit of the Marquesas for the barren low-lying, flat coral atolls of the Tuamotus where the highest point is the top of a coconut palm and not much else grows.  Here too are stretches of pink and white sandy beaches, encircling lagoons with luminously clear waters,  flat anchorages, exciting pass diving with multitudes of sharks and big pelagics, fabulous snorkeling in a vibrant aquarium of fish and coral, and pearl farms on stilts churning out those famous Tahitian shiny black gems.

We had also traded the relative ease of straightforward, undemanding navigation in the Marquesas for navigation that would take much cautious vigilance as we maneuvered through this scattered low-lying land, around many imperiling obstructions within the atoll lagoons (reefs, coral heads and pearl farm buoys), and through tricky passes into and out of them.  These were truly new adventures of a different sort!

Introduction: The Tuamotu Archipelago


The 77 atolls of the Tuamotu Archipelago cut a diagonal swath through the heart of French Polynesia, scattered over 900 sq. miles of empty sea in an area of the Pacific Ocean the size of Western Europe.  It is the largest chain of its kind in the world. Typically described as a tropical landscape,  you could hardly call it that, for there isn’t much land above the ocean surface; the atolls barely rise out of the sea (generally less than 15’). It would be more accurate to call it a sky-and-seascape .......frequently filled with rainbows and Rorschach sunsets.  None of the Tuamotus have yet to be lost to global warming and the anticipated rise of global sea levels but some of them are certainly in line as prime candidates. 

Although “Tuamotu” has been translated as “many islands”, they are not true islands at all but ring-shaped atolls.  Instead of solid dots as depicted on a map for a typical island group, the Tuamotus look like a series of deflated zeros, carelessly flung rubber bands.....or, to use a local image, like floating firi-firi, the elongated sugary Polynesian donuts that are a breakfast staple in this part of the world.

Each atoll is a circular necklace of small emerald green beads - hundreds of low coconut palm-covered coral islets  (called “motus”) -  strung together by domes of sandy spits and crusty shoals of sharp coral reef.   On the outer fringe of the necklace, the incessant hammering of foamy seas thrown into the air by ocean swells eerily appear like evanescent white geyser plumes, working to level what edges still exist on the treacherous fringing reefs, which can extend outward for hundreds and hundreds of yards.  Hoas, small channels of water gushing over the outside reefs, replenish the interior lagoon with nutrient rich seawater.

Inside this necklace is cradled a lagoon of spectacular hues of “transcendently blue water” (Robert Louis Stevenson).  “Le bleu que fait mal les yeux” wrote a French author of the Tuamotus.   “The blue that hurts your eyes”.


It is a good description for what you see and feel in this part of French Polynesia. Glorious colors of bright blue sea water that burn an impression in your brain.  Could the dictionary offer help in putting the sight into words? Aquamarine, turquoise, azure, lapis, cobalt, scorching sapphire, searing cerulean.  All inadequate.   Many a friend has said they wished they were an artist so they could capture the colors somehow but I can tell you they are nearly impossible to render.  No paint or photograph or sparkly glass beads can do them justice.  They are something you have to behold with your own eyes to fully grasp....and also, more critically, to read in order to safely enjoy and survive your cruising here.

Why “Dangerous Archipelago”?


The low-lying aspect of the atolls was a major reason they were dubbed the “dangerous archipelago” by one of the earliest European explorers, Frenchman Louis Antoine de Bougainville in 1767.  “From the deck of a small yacht your horizon is not more than 3 miles away and for even the tops of the palms to be visible you will be as close as 7-8 miles, when you are close-to... and the sounds of the wind and the sea often mask the sound of the breakers” (Underground Pacific Island Handbook, 1997).  When finally visible, the atolls are very flat, spiky like a palm-tree pincushion, “deformed with disproportioned trees like bristles on a broom” (Robert Louis Stevenson).  Because Bougainville found that the Tuamotus were so difficult to navigate and their barrenness offered few resources, he and his crew did not stay long in this “bad country”.

In 1888, more than a century later, Robert Louis Stevenson arrived in his schooner Casco and echoed Bougainville’s observations.  “In no quarter are the atolls so thickly congregated, in none are they so varied in size from the greatest to the least, and in none is navigation so beset with perils, as in that archipelago that we are now to thread.” He expounded further, cataloguing the complications and his concerns: “the trades (winds) are confounded by the multiplicity of reefs, the wind intermits, squalls are frequent from the west and SW, hurricanes are known.... the currents are inextricably mixed, dead reckoning becomes a farce, the charts are not to be trusted, and such is the number and similarity of these islands that, even when you have picked one up, you may be none the wiser.  The reputation of the place is consequently infamous; insurance offices exclude it from their field; and it was not without misgiving that my captain risked the Casco in such waters.  I believe, indeed, it is almost understood that yachts are to avoid this baffling archipelago.”

This attitude of avoidance persisted until only recently. Written in 1997, the Underground Pacific Island Handbook states: “It was not so long ago that most cruising plans aimed at only sighting and passing the Tuamotu safely.  Today (referring to 1997) a few atolls are regularly visited (Manihi, Ahe, Rangiroa, and Takaroa)...because they are closest to the usual route to Tahiti (from the Marquesas)”.   We have heard stories from Chuck’s sister and brother-in-law about how daunting it was to use a sextant to navigate through here during their circumnavigation in the late1970’s on svGambit.

The introduction of the GPS changed everything. Now, with the existence of our sophisticated navigational technology and programs, the broader Tuamotu archipelago is widely explored and enjoyed recreationally by larger numbers of cruisers each year.  (Moruroa and Fangatufa atolls were ground zero for France’s nuclear testing in the 1960’s are still off-limits). 

Yet the challenge still continues - the dangers of traveling in these waters is not to be underestimated.   Heightened caution remains the watchword and strict attentiveness to the weather and your surroundings is essential.  And so it is true today too that the Archipelago gods demand a few sacrifices.  Every year, even with all our advanced gadgets and aids, the Tuamotus take their toll as several boats end up on the reef and are lost.  According to a marine surveyor we met in Tahiti, the average casualties expected number 3 per year but this 2015-16 cruising season was for some reason abnormally high with at least 4 boats wrecked and 6 damaged.

It’s a Challenge


As in many things in life there are two things that make a big difference:  location/location/location and timing.   Here is a simplified description of the optimal cruising process in the Tuamotus: 1.Sail to an atoll that has a pass and approach the pass in the daylight.  2. Enter through the pass at slack water.  3. Now you are inside the lagoon and can proceed to go to your destination.  4. Once you have reached where you want to be, drop the anchor and relax!  Sounds easy on the surface? Not so fast.  Looking at the reality behind what it takes to accomplish these things in detail reveals more explicit reasons why the Tuamotus cause such anxiety.  Let's take them one by one.

1.  The  Approach  


Many atolls have either no pass or one too shallow for sailboats, only navigable by small local boats.   We have heard of sailboats anchoring on the shelf of the outer reef and dinghying in to the lagoon but this is a pretty rare occurrence.  What would normally, distance-wise, be just a day-sail between two atolls often turns into an overnight because of the timing needed to safely exit the pass of one atoll and arrive at the pass of another.  Since the goal is to be at the passes at slack tide and in good daylight to be able to see the hazards, we often had to slow down to time our approach, delaying our entry and prolonging what would have been a shorter, speedier trip.

 2. Timing of entering and exiting a pass


The pass is a narrow channel that allows connection between the lagoon and the sea.  Entering and exiting a pass is sometimes tricky because of the strong currents that rip through it, (sometimes over 5 knots), often creating breaking seas, standing waves (sometimes up to 6 feet), rips and grippingly dangerous currents.  Areas of shallow water, reef sides, and fish traps can narrow the navigable path.  It is necessary to maintain speed for control; in Tahanea we watched friends on a catamaran struggle to barely power through the pass at the wrong time when the current was strongly against them, fearing for their loss of control.  In Raroia, we heard that even a large island supply ship turned around after attempting to enter the pass during rough water and waited outside for a few hours for better timing.

It is optimal to transit a pass at slack water, between high and low tides so that the water is flat.  But how do you know when slack tide will occur?  Therein lies the difficulty.  The South Pacific Islands Pilot, obsolete for most cruisers,  tries to pin it down by coordinating water flow with the moon’s rise and set.  Nowadays most of us attempt to use a computer program called “The Guestimator”, developed by Gram Schweikert (svVisions of Johanna) in 2010.  This is a formula using nearby tide tables that is offset by variables such as local weather patterns (i.e. high winds, squalls, and rain).  But it is stunningly inaccurate; days of heavy southerly swells or strong prevailing winds may push more water into the lagoon over outer reefs and create a different condition than predicted....“even to the extent of sometimes maintaining a continuous outflowing stream”. (UPIH).  But it is a good starting place for a wild guess. 

Here’s the method that we used to try to predict slack water.  First we looked at the French tide tables available for Rangiroa and calculated a longitudinal offset depending on whether we were east or west of that atoll.   Then we looked at another tide program (British) called TotalTide that referenced a number of atolls in the Tuamotus, finding the one that was closest.  Thirdly,  we compared these with the Guestimator (making sure we had the current year’s tides tables loaded as input).  Never once did all three agree but we tried to reconcile them as closely as possible.  Then we calculated how much wind and sea state we had had in the last 3 days to make some additional adjustments.   Finally we rolled the dice, attempting to get to the pass a few hours before what we estimated was slack water to wait and see the conditions for ourselves.

Perhaps the most reliable time estimate for slack water is derived from boats that are anchored inside the lagoon or from local diving outfits that have been experiencing the conditions first-hand up to the moment.  That information was obtained either through the morning radio net (Polynesian Magellan Net on the SSB), via private sailmail/winlink communication, or by calling on the vhf radio when in closer range. 


As a side note, in addition to closing everything up on the boat  (hatches, ports, companionway) before we go through a pass, we always had our harnesses on and clipped in for extra safety.

3. Navigating inside the lagoon


The lagoons are rife with dangerous hazards:  (1) most significantly coral heads, or bommies, that rise abruptly from the lagoon floor (as much as 80 feet) to lurk just below the surface, shallow enough to do major damage, (2) small islets barely exposed and (3) pearl buoys that float a series of underwater lines of pearl oysters from various farms.  Some of these floats, tied to each other, are active and plainly visible on the surface but some may be abandoned and submerged a few feet below the surface.

It is critical that you move around “with a pair of eyes” - a person who acts as a lookout on the bow of the deck or even from the spreaders - the higher the position the better. It is most prudent to move around the lagoon only between the hours of  9 a.m. until 3 p.m. with the sun behind you for optimal ident- ification of underwater obstacles and bommies. 

You need to be able to read the colors of the water.  Once the sun is in front of you, the water becomes flat and you are blinded to the water depths.  The spotter should be prepared with a hat, sunscreen and polarized sun-glasses; binoculars are an aid.  

Many of the major atolls we visited had channels with markers (lighted or not)  that guide the weekly supply ships from the pass to the main villages.  You still need a “pair of eyes” in these channels - it is surprising how many pearl farms have located buoys out in the middle of them.  There are standard red and green markers delineating the channels (using the international system as opposed to the US system) and other posts with topmarks of different shapes and colors, the cardinal buoys, that you need to be familiar with.

In our partnership process,  Chuck first looked at our Open CPN program to see if the area we intended to transit had a chart (98% of the atolls were either not charted or majorly inaccurate).  Second he switched from Open CPN to the Google Earth chartlets (saved images) he had made previously with the GE2KAP program when we had internet and plotted a path from the pass to our destination that looked clear of obstacles.  Not all bommies show up on the Google Earth snapshots and clouds will often obscure your reading.  Linda would maintain a lookout on the bow and we would continuously check with each other about what we expected to see and what was actually before us, dodging and changing course when called for.

 4. Anchoring


Anchoring in the Tuamotus without fouling the anchor on bommies became an art that we got better at with experience.  This included learning how to buoy the anchor chain.   The ideal is to drop the anchor in a patch of sand with 360 degree swinging room from any coral heads.  This is often a near impossibility since the bommies are so numerous and closely spaced (although some anchorages are worse than others) and the water is not always clear enough to discern them.

Linda would try to locate such a patch at a water depth of less than 30 feet - a depth that Chuck could free dive to unwrap the anchor if necessary.  We would then let out the appropriate scope and back down to set the anchor, listening to/feeling the chain on any coral.  Next we would slowly bring in the chain and attach three to four buoys along the chain using hard plastic pearl floats we had scavenged on the beach to keep the chain above the bommies.  The first buoy is attached at a distance along the chain at 1 1/2 times the depth of the water (i.e. if we dropped the anchor in 30 feet of water then the first float would be at 45 feet along the chain);  the subsequent  floats were set at about every 30 feet.  At first we used soft fenders for our floats but that didn’t work well because the water pressure flattened them as the chain stretched out.   We usually jumped in the water to look at the anchor and its placement and checked out nearby bommies with our handheld depth sounder to make sure we had a safe swinging area if the wind were to switch.

Speaking of switching winds, this brings up another hazard of cruising in the Tuamotus.  “Rapidly changing weather patterns call for flexibility and good navigational skills” (Mr. John Guide).   You may be comfortably anchored on a side of the atoll with protection from a southerly but if the wind switches to the north you could find yourself fighting a storm on a lee shore with a lot of miles of fetch coming toward you. This is not only uncomfortable but very dangerous.  And you may not be able to move to a different side of the atoll for protection:  the atoll may be too large - the opposite side could be over 30 miles away (which is why we did not go to Rangiroa) -  or it may not be safe to move because of nighttime or inadequate visibility to see hazards. Our friend on svBlowin Bubbles recounts a harrowing night in Fakarava:  “Accompanied by svBeachHouse, and svSwift Sure, we all made our way from the south pass  halfway up the inside of the atoll with a weather forecast that called for strong North Winds.  What we got was SOUTH WINDS, which put us on a lee shore with dangerous rocks behind us.  At 2 a.m. all three of us started our engines and idled into the wind with the anchor down for three hours until day break when we got the heck out of there and back to the south pass. That was one our scariest nights yet!”  


A watchful eye on weather forecasts was a constant daily activity.

The Cruising Guide Compendium from svSoggy Paws is a very valuable guide to the Tuamotus and is available free from their website.  It is a joint effort of many cruisers over the years and we have contributed to it by making updates, filling in some voids, and listing some of our waypoints for pass entrances, routes, and anchorages.   Since the internet access in the Tuamotus is very limited, it is highly recommended that you download any internet resources before you go.

MORE PHOTOS: In the "Photo Gallery" for Passage Note #86

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