Saturday, July 28, 2012

Tuamotus Passage and Our First Atoll

After a five and a half-day passage, we are safely bobbing at anchor in the lagoon at Tahanea atoll.

Although this was a shorter passage, it had many moods and was in some ways more wearing than our longer passages. When we left Ua Pou (our last island stop in the Marquesas) last Sunday, the passage started out with nice trade-wind sailing in a beam to broad reach under a single-reefed main and full headsail. We reached right into a windless hole. Our speed dropped to under two knots. Since we had plenty of fuel to make it to our destination this time, we decided to motor to find the wind. We motored for a night and a day, and then we found the wind: lots of it. The next three and a half days were spent sailing hard on the wind. The first two days and two nights we had over twenty knots of wind---typically in the 22 to 23 knot range---with gusts up to 28 knots. A double-reefed main and staysail combination served us well as Silhouette pounded to weather and Patrick and I tried to hang on.

We were both feeling worn down when we left Ua Pou (I was recuperating from some tropical bug), and since the passage was not going to last for three weeks, we took three-hour watches instead of our usual four. This was a good call as the wind and sea conditions were tiring.

We had several small breakages along the way. In the wind, the bimini canvas starting ripping apart and will have to be resewn and fortified. The tie to the mesh bag we had swinging over the stern exploded, and Neptune extracted two of our precious pamplemousse as toll for the passage (luckily, Patrick was able to save the rest, including one caught by the wind vane frame!) A small piece of cover board covering the deck to hull joint under the caprail was ripped off by pounding into the seas and will have to be replaced. And we discovered that our center hatch leaks when we take waves hitting the cabin top at an angle. We will have to reinforce the gasket material. We could definitely tell the boat was ridden hard during our passage to the Tuamotus.

The wind lightened up to under twenty knots (fourteen to nineteen) during the last twelve hours of the passage; the seas came down a bit; and we added a partially furled headsail to our reduced sail combination. This gave us the added speed we needed to make it to the pass at Tahanea atoll by slack water, and we flew along at six or seven knots for the remainder of the passage.

Passes in the Tuamotus are notorious for being dangerous due to strong currents that run through the narrow opening during the incoming and outgoing tides. Therefore, it is the conventional wisdom to enter the passes at slack water. If the wind has been blowing at twenty knots for several days, like when we arrived, the passes are even more dangerous, because all the water carried over the reef by the wind into the lagoon has no way out but the pass. In this case, there can sometimes be no slack water because even at slack water there is outgoing current.

We had picked an "easy" pass for our first atoll. The maximum current in the middle pass at Tahanea (Passe Manino) under normal conditions is only four knots. There are three passes in this atoll, which reduces the force of the current through one narrow opening by spreading the flow over three openings. There are no coral heads obstructing the opening of the pass.

Our best estimate of slack water using the available sources was 12:45 p.m.. At 12:43 p.m., just as we were lining up to enter our first pass through a coral reef into a lagoon, the engine died. Our engine has died on only one other occasion: when the fuel intake line was clogged by aluminum shavings left in our new fuel tank by the welder. We did what any prudent sailors would do: We put up a sail and tacked away from the pass. Damn! After all that effort to get here, we were going to miss our chance to enter the pass and have to wait.

I steered into the wind, keeping the boat going as slowly as possible, while Patrick went below to trouble-shoot. He quickly deduced that the problem was a clogged fuel filter. We had used so little fuel since leaving the Galapagos, we had only been putting fuel into one tank, topping it off with jerry cans. This violated Patrick's normal procedure of only adding fuel to our bilge tank and then transferring it to our cockpit tank---passing the fuel through a fuel filter en route---so that only filtered fuel reached the "day use" cockpit tank. Since we were purchasing fuel from a gas station, we assumed that the source was good and the fuel clean. We must have gotten some contaminated fuel in Taiohae, however, since the fuel filter was clogged. Patrick switched to the bilge tank and other fuel filter, and the engine started.

With the delay, we were an hour late entering the pass. "Late" is a relative term, however, as our estimated time of slack water was itself only an estimate. Through the binoculars, I could see white water ahead, but I couldn't tell if there were white caps in the pass or standing waves. We knew we shouldn't enter the pass if there were standing waves in the pass. When we were right on top of them, we were able to see that there were in fact standing waves in the entrance. They were only two to four feet high and were concentrated mostly on the left side of the entrance to the pass. Patrick elected to go ahead. Keeping an eye on the boat speed through the water and referencing it to the GPS speed over ground, Patrick was able to assess the amount of current in the pass and to determine whether we had enough engine speed to power against it. Once we got out of the entrance and into the pass proper, the standing waves settled down. Soon, we had entered the lagoon and looked for a place to anchor.

We are not in an ideal spot as we are anchored in sand surrounded by coral heads. So long as the wind continues blowing (it is down to nine knots this morning) and we are pointed into the wind with our anchor chain stretched out, there is no danger of wrapping our anchor chain around a coral head. However, once it calms down, the scope of our anchor chain may be reduced if it wraps around a coral head, and we will have to free dive on it to un-wrap it. Many sailors buoy their anchor chains with fenders or floats when anchoring around coral or use a combination of chain and floating line when anchoring for this reason. There are many anchoring options here, and we may move to a better location today.

Meanwhile, we sit here a little bit shell-shocked, after our first good meal and good night's sleep in days, enjoying our morning coffee and the beauty of our surroundings. The high volcanic islands of the Marquesas have been replaced with the low topography of the coral reef. The thing that has suprised me the most is just how big an atoll and its associated lagoon are. You know it was a rough passage when you enter a lagoon, it looks as if you are anchoring in the middle of an ocean, and you happily declare, "The wind has almost completely died down!" when there are still ten knots. If we look across the lagoon one way, we cannot see the other side. With the wind-blown waves from the past few days, it truly looks as if we are anchored in a vast ocean, albeit one with smaller wave height than the true ocean outside. If we look to the other side, towards the edge of the tropical reef we are anchored next to, it looks as if one might imagine a coral atoll to look: white coral beach, green palm trees, and turquoise shallow water through which the coral heads bloom.

Patrick observed that the lagoon is where a volcano used to be. "Imagine how big it was," he said, "and imagine how long it took to wear it down." He wondered how many years it would be until the Marquesas look like this. The atoll is approximately 24 by 9 miles in size now.

I am also surprised at the vegetation. I had heard that the vegetation is sparse on coral reefs, consisting mostly of palm trees, but I see understory on the reef before me. It is more lush than I imagined. Since this is my very first atoll, I will have to reserve judgment on that until I've seen more of them.

For now, we are very happy to be here.

Posted from Tahanea atoll via Ham Radio.

4 comments:

  1. www.canyonmistvineyards.comJuly 31, 2012 at 6:52 AM

    I must give Patrick a thumbs up for risking the passage into the atoll and for being such a great sailor. I saw on the sat map where you went through. Truly impressed with you guys and your resilience. I will enjoy a glass of wine tonight thinking of you and your journey. Here is to Patrick and Kirsten. Sandor

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  2. Hair raising adventure, Kirsten. The whole crossing sounds quite tense albeit a great adventure now you're safely in the harbor. But, you still have to sail out!

    By happenstance, I recently read the book 'Call it Courage' to the boys. It takes place somewhere in the area of the world that you are in now. I have a much better appreciation for the setting of the book now that I've read your blog these last few weeks....

    Anyways, smooth sailing to you on your next leg.

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    Replies
    1. What is 'Call it Courage' about? Haven't heard of it. I read one you might be interested in: 'Snowdrops.' It's a suspenseful one, set in modern Russia. It will strike some chords.

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  3. www.canyonmistvineyards.comAugust 4, 2012 at 11:55 AM

    I see you have moved Hopefully a little less exciting than the last time. I am amazed at the topography and the fact that you are in the middle of the Pacific Ocean on a 38 foot vessel. Awesome.
    Sandor

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