Floating the chain - cruising the Tuamotus

A three-day sail northeast from the Isles Gambiers took Saecwen into the heart of the Tuamotus archipelago. Comprising over 70 atolls that stretch across 800 miles of the South Pacific, they form the largest chain of coral atolls in the world. Dozens are “closed” to the ocean, with no passable channel through which a deep keeled sailing vessel can enter their inside lagoons.  However, many atolls do provide access from the ocean with passes through which a yacht can enter to be able to explore inside these truly extraordinary places.

Negotiating the passes is the first of many challenges when cruising the Tuamotus. With a tidal range of around half a meter, it’s through these narrow outlets that the entire lagoon has to empty on a falling tide. In the case of the bigger atolls, this constitutes a phenomenal volume of water having to escape through the narrowest of gaps. On top of that, if a big ocean swell is running (as is often encountered in the South Pacific) further massive volumes of water are pushed into the enclosed lagoon of the atoll over the lengths of more exposed reef. This inevitably means even greater quantities of water are trying to exit through the passes, often giving a tidal flow of over 10 knots at peak outgoing tide. In the event of this current flowing against a fresh wind, huge standing waves and boiling seas, which we would more readily associate with Portland Bill or the Gulf of Corryvrackan, are regularly witnessed.

Amanu Atoll, Tuamotus

Timing your entrances to the atolls is therefore of paramount importance and whilst excellent French government tide tables exist for the islands and more sophisticated algorithms (such as “The Guestimator” as found on www.thefloatinglab.world) have been devised to adjust for the additional surge effect of waves and swell to help you predict slack water, determining your best time of entry remains a somewhat inexact science.

Approaching Amanu Atoll's pass

In Saecwen’s case we arrived too late for our planned moment of entry into Amanu, our first Tuamotu atoll. To await the next opportunity, we spent most of the night hove to outside in the ocean and when we did enter the following morning we had to motor in over 4-5 knots of outgoing tide. It was with a sigh of relief that we cleared our first pass and entered the relative calm of the lagoon.

Crossing an uncharted atoll - a bommie minefield

Once this first obstacle of the pass has been overcome, you are immediately presented with the next challenge: navigating across the atoll to find your anchorage. The vast majority of these atolls are completely uncharted and are littered like a minefield with huge coral outcrops known as “bommies”. Google Earth does an excellent job in showing you where many of them are located, but at the end of the day there is no substitute for navigating with your own eyes, which requires strong light with the sun either overhead or behind you.  

Exploring the atoll's rim

During our 10 day stay in Amanu, a Canadian flagged catamaran decided to sail across the atoll early in the morning west to east with the sun in their eyes. They crashed full on into a large bommie, holing both hulls and seriously damaging a keel. Their distress call to other yachts stated that they had hit “an uncharted bommie”, which somewhat missed the point that the entire atoll is uncharted and they had broken one of the key rules in the book by moving in poor light. Thankfully with the help of other yachts they were able to patch up the hulls and start making their slow way to Tahiti where they can haul the boat out for full repairs.

Anchoring amongst the bommies

Once you have finished weaving your way bommie-dodging across the atoll to your chosen anchorage, you are then presented with your next major challenge: anchoring. The Tuamotus are entirely built around living coral reef and within each atoll coral outcrops abound everywhere. To anchor you must first find a clear patch of sand into which to drop your anchor. However, it is almost inconceivable that this patch of sand will be big enough to allow the full scope of your anchor chain to swing freely if for example there was a shift in the wind direction (which we were to soon discover happens frequently). The potential therefore of tangling your chain up in the coral and completely immobilising your boat is huge.

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Floating the chain

The solution to this issue is “floating the chain.” By suspending the anchor chain from a series of floats you can effectively get the majority of its scope clear of the seabed and thus prevent entanglement with surrounding bommies. In Saecwen’s case we acquired four large plastic floats from friendly pearl farmers in the Gambier islands and with a couple of our larger fenders these enabled us to very effectively suspend up to 30 meters of our heavy 12 mm chain to give us sufficient swinging room. It took several attempts for Heloise and I to master the art, but we soon worked out that once we had let out a scope of chain equating to 1.5 time our depth, the first float was attached and then the others every 5 meters of so. The use of small stainless-steel carabiners enabled Heloise, who is officer in charge of the foredeck, to quickly clip the floats whilst rapidly deploying more chain to get the anchor set.

Floats and anchor buoy nicely lined up

Once all this was done, we would then snorkel over the anchor to check that a) it was properly dug in and b) it was immediately clear of bommies. On more than one occasion it proved that in setting the anchor too aggressively when reversing the boat we had dragged it too far from the original sandy patch, necessitating the whole process to start all over again…

Chain suspended beneath our floats

So once safely anchored, with the chain suspended beautifully beneath our proud array of floats, we could finally relax and start to explore and enjoy this extraordinary tropical paradise. In Amanu, one of the smaller, more remote and wild atolls, for several days we kayaked for miles along the wild shoreline stopping to snorkel and beachcomb. The only other people we encountered was when we stopped to chat with a couple of islanders  harvesting copra from dried coconuts on one of the remote small islands (or motus) that make up the rim of the atoll.

Beneath the water the coral appeared very healthy and the abundant mass of fish was a true wonder to behold.  Once we started to overcome our natural apprehension of swimming with so many black tipped reef sharks all around us, we snorkelled around incredible coral structures teeming with stunning multi-coloured fish.  Every snorkel we would encounter new species and elect new favourites such as the bright yellow striped butterfly fish, tiny black and white damsels, the speedy Picasso trigger fish, blue unicorn fish who loved nibbling the weed off our wind vane’s rudder – and the remoras who slip alongside Saecwen’s keel in the way they do with the sharks they clean. The list is infinite... 

Black tip shark

In one anchorage we witnessed the remarkable sight of a huge bait ball of thousands of shad (sardine-like small fish) forming under the boat, which in turn were being hit on by a pack of large dog-tooth tuna, with many large sharks in attendance to pick up the scraps. It gave us quite a shock when we innocently snorkelled right into the middle of this extraordinary spectacle.

Whilst relaxing in paradise was our main objective, sadly it was not to always be the case. In theory a coral atoll should provide a yacht with the potential for shelter from wind in any direction. In practice however it also provides the potential for a 360 degrees lee shore. For example, having moved the boat 16 miles to the very north of Amanu to seek shelter from three days of forecasted northerly winds, whilst out kayaking we suddenly saw huge black clouds rapidly forming to our south. The next thing we realised that the wind had then shifted fully from this unpredicted direction.

Tuamotus squall coming out of nowhere

After frantically paddling the three or so miles back to the supposedly safely anchored Saecwen, we now found ourselves on a lee shore with a violent rain squall hitting us. I had foolishly not allowed enough swing room for this eventuality (consistent northerly winds had after all been definitively forecast) – and we clearly swung round into too shallow water where we could bump the bottom in the event of a steep sea building up. Moreover, if the wind were to veer back to the north via the west, we were now in line to swing directly into a huge bommie on our port quarter. With late afternoon light rapidly fading it was clear that the boat was in danger and with a heavy heart we reluctantly upped the anchor, with its attendant chain of floats, and moved out to deeper water. Using google earth and some coordinates another yacht had given us of a clear anchoring patch, we re-anchored blindly in the twilight, hoping that our anchor would find sand, which thankfully it did. Shortly after doing this the wind swung violently into the west – which would have smashed our vulnerable stern into that menacing large bommie had we remained in our previous spot.

From storm to dead calm - our floats preventing the chain tangling in the coral. below

By dawn the wind had completed its 360-degree revolution, gently veering back into its forecast northerly direction as if nothing had happened. Everything then calmed down and the most stunning sunny day ensued. That night we found ourselves at anchor in mirror flat water with the multitude of stars of the magnificent southern hemisphere tropical night sky perfectly reflected in the sea all around us. It was as if the sea was lit up with thousands of floating stars. We both agreed that we had never before been anchored in a more uniquely beautiful place.

Snorkelling off the atoll

As we continue to negotiate the atolls of the Tuamotus we clearly are getting wiser to their unique ways. Key lessons learnt include: only move across the atolls in good light (or if you are following a track of a previous safe crossing); practice floating your chain before you have to do it in earnest, and then when selecting your anchoring spot always plan to be able swing safely through the entire 360 degrees. Unlike in the Caribbean, where the wind consistently blows from one direction, in the South Pacific the wind can suddenly change 180 degrees, often accompanied by a violent rain squall. In summary, you must prepare for every eventuality.

The rewards for cruising these extraordinary atolls and their lagoons without any doubt more than compensate for any of the challenges they readily present the cruising sailor. In our case it was certainly worth the 14,000-mile sail from Lymington to have the privilege of exploring these truly wild and unspoilt ecosystems where’s man’s impact continues to be minimal, and nature can be experienced so intimately in its rawest beauty. Writing now from the beautiful atoll of Makemo, we are already studying the pass tide tables as we plan our routes to visit more of the Tuamotu archipelago.