The Tuamotus are indisputably beautiful. But the idyll of the scenery is balanced by the challenges of the sailing. The name Tuamotu translates to “Dangerous Islands”, and this name is richly deserved. There are two main issues with sailing in these islands – navigating the narrow passes to enter the lagoons, and then avoiding large coral heads once inside.

Entering the pass at Amanu with 4 knots of nose current
Amanu church and town as seen from the pass

Access to the central lagoon of an atoll is almost always made through a narrow pass that has been worn in the coral by reversing tidal currents rushing in and out twice a day. With only a few narrow openings to drain the large interior lagoon, currents can run very swiftly, as fast as Oso can motor. And strong currents flowing into the wind and waves causes steep standing waves – at best, this can be very uncomfortable, and at worst, boats can be washed into the coral rocks that line the sides of the passes.

Angie peering into the high-tech ‘room darkening’ viewing box (constructed of two cockpit chairs) to check our position on the satellite charts and make sure we steer clear of all the bommies as we make our way across the atoll
Sailing from one anchorage to another in Amanu – constantly on the lookout for bommies

So timing the passes to transit at around slack current is the prudent approach. However, the currents through the passes mostly defy prediction. Strong winds and larger waves can cause extra water to flow into the lagoon – that water has to exit through the narrow pass, so sometimes the extra water flowing out of the lagoon completely eliminates the flood current. But sometimes not, so the state of the art approach is to sail close to the pass, and then wait for good daylight to decide wheather conditions are reasonable enough for entry – if not, then sail around for an hour or so before checking again.

Another lovely Amanu anchorage
There are no roads or trails where we anchored in Amanu or Tahanea. But nearly every day we went ashore for a walk, either on the lagoon side or ocean side or sometimes through the coconut trees in between
Shore outing as the sun is beginning to set

The second challenge is that the lagoons of many of the atolls are mostly or completely uncharted. Average depth in the lagoons is around 100’/30m, but large coral heads (locally called “bommies”) grow from the bottom to just beneath the surface of the water. With the sun directly overhead and slightly behind the boat, the bommies are easy to see; but with cloud cover or with glare from sun ahead of the boat, it’s impossible to locate the bommies until it’s too late.

Tropical paradise
We saw lots and lots of black tip reef sharks in the Tuamotus. They are curious but also shy and a bit timid.  When we were swimming they would often come near to check us out but then decide we were big and not food and swim away. They also liked checking out our paddle board fins and the foil on our wingfoil board.  We often had one or two swimming around Oso when anchored in the atoll

Luckily for us, some enterprising sailors have georeferenced satellite views from publicly available online maps, and using these allows us to locate the large majority of the hazards. But there are still patches of hazardous, shallow coral that are too small to be visible in the satellite images, but shallow and large enough to hole the boat. While in one atoll, a large catamaran struck a bommie in low light conditions, opening each hull and bending a rudder. Sail carefully!

Hermit crabs making a feast of a discarded coconut
Perfect dinghy parking
Oso’s crew was gifted an open coconut from a fellow cruising boat – yum!

Because coral is slow-growing and susceptible to damage from anchors and chain, we (along with most other sailors) take special care while anchoring. After locating a sandy spot as large as possible, we drop the anchor and make sure that it’s dug into the sand, not hooked around any coral. Next, one of us jumps in the water with a mask and fins to survey the area. Once we have an idea of where the closest coral is to the anchor, and how far above the bottom it has grown, we can make a plan for floating the anchor chain above it.

Coral bommie and small black tip shark in our anchorage – these bommies are why floating the chain at anchor is a necessity
Sunrise view of our floating anchor chain
A calm morning provides a good view of the pearl floats and Oso’s anchor chain
A bommie right off the stern in our anchor spot. Jumping into the water to survey the anchor location and the swing area after anchoring was an important part of the anchoring process in the Tuamotus. By doing so we made sure our anchor was well dug into the sand, our anchor and chain was not at risk of damaging the coral, and that all the bommies were low enough that Oso’s nearly 8ft/2.4m keel and rudder would safely swing over the top of them without touching

Instead of just laying chain on the ocean floor as the boat slowly backs away from the anchor, we attach floats to the chain every 20’/6m or so. Because of the weight of the chain, the first float is completely submerged, but the chain is held off the bottom and away from the sensitive coral. Each subsequent float sits a bit higher in the water, until the float closest to the boat is right at the surface.

Our time in the Tuamotus wasn’t all navigating passes and avoiding bommies and anchoring – we enjoyed plenty of relaxing, paddle boarding, swimming, and attempting to learn foilboarding
Angie wearing her camouflage sunshirt
Paddling back to Oso

By varying where along the anchor chain the floats are attached, we can arrange the anchor chain such that it will float clear of any coral in the area. Just like in Patagonia, where we tied the boat to shore each night, our first several tries of floating the chain provided plenty of learning opportunities! But after a few cycles, we started to feel like competent tropical coral anchorers.

We shared an anchorage with a fellow OCC boat SY Saecwen, a beautiful British ketch
Charlie and Heloise had us onboard Saecwen for an absolute feast!

With the French Polynesia 90-day visitor visa clock ticking, after three weeks in just two atolls it’s time to move on. Oso reluctantly navigates the pass at Tahanea (at nearly the exact time forecasted for slack current, but with several knots of current running in the wrong direction anyway) and sets sail for Tahiti. The crew hopes to be back one day.