July 04, 2012
A train leaves the station at 12:05 headed north. Another train leaves the same station headed South… What’s this have to do with white-water rafting? It resulted from failing to find an adequate solution to a similar word problem.
Atolls are large bodies of water surrounded by a thin strip of land made of coral that has built up over the millennia. The amount of water enclosed by the land can be huge. This water runs in and out of the atoll with the tides through narrow passes to the ocean. The current in these passes can sometimes reach 23 knots for particularly huge atolls with a single pass. Typically, the current can reach 5 or 6 knots (basically miles per hour) in most passes. Since our boat can only travel at about 5 or 6 knots, it leads us to this. We needed to leave Fakarava at such a time that we could travel with the outgoing tide in the north pass. The pass was one hour away from the anchorage. So far no problem but part two is that we needed to arrive at Toau at high or low tide so there wouldn’t be much current in that pass. Toau is about 30 miles away, at 5 knots boat speed, that’s six hours.
Part three is that we needed to both leave Fakarava and arrive at Toau during a time when the sun would be high in the sky so that we could see any coral heads in the water that might be shallow enough for us to hit. Now add to that the fact that of the various tide tables we have – tables showing when high and low tides are at various locations – are in total disagreement as to when favorable tides will occur. None of them seem to be even close to correct and this is a problem that everyone we’ve talked to seems to be having.
Since ax + by/cz + 32.8 can never equal m, we headed out at daybreak to hit the Fakarava pass with outgoing tide. That was the best we could do. I guess another boat worked the same equation and came to the same conclusion as they headed out at the exact same time we did.
All went well for the hour-long trip to the pass as we followed the other boat. All looked well as they turned towards the pass just ahead of us. Then we saw it. Cyndi asked “those big breaking waves are on the reefs to the sides of the pass, aren’t they?!?” Nope. They are all the way across the pass.
The water pouring out of the atoll into the ocean, meeting the ocean waves, causes very large waves that don’t move much – standing waves. They showed up on radar like a land mass between us and the ocean. We watched as the boat ahead of us slammed into the waves and rocked like some kind of demented carnival ride. I lost my nerve and decided to turn around and try again later, when the current wasn’t so strong. I thought how lucky we were to have someone test the waters ahead of us.
Now we were to have a new lesson in navigation software shortcomings. As we’d turned tail and ran back inside the atoll, I watched our position on our electronic chart plotter. It displays a little line in front of our boat that shows where we should be in 30 minutes at the speed we’re traveling. The little line was way ahead of our boat. Wow, we must be making great speed. Yep, a look at the speed through the water showed we were moving at about six knots but something just didn’t feel right. We didn’t seem to be getting any further away from the line of breakers. In fact, we seemed to be getting closer at an alarming rate. What’s the deal?
Turns out that the plotter uses the little paddle wheel under our boat to judge the boat speed and it can’t tell if the paddle is turning forwards or backwards – just that it’s turning. Ours was turning backwards, fast! We were actually moving into the pass, backwards at about six knots despite running the engine at full throttle, forward. We were going through the pass and the breakers one way or another, either forwards or backwards. We opted for forwards and turned around quickly. Now there was nothing to do but hold on for the wild ride.
We have no pictures of this because I was too terrified to be alone in the cockpit for even the seconds it would have taken for Cyndi to grab a camera. (I wanted to be close to her during my final seconds on earth.) OK, maybe it wasn’t quite that bad, but it was rough. We slammed through six foot breakers with green water coming over the deck. The cockpit looked like a swimming pool – a very angry one – with all the water that had broken over the boat. I was soaked. Everything was soaked. The white-water ride only lasted a few minutes, maybe five at most, but it seemed like an eternity while we were in it. After we were out, and my shaking subsided, it didn’t feel that bad.
In retrospect, I guess we were really in no great danger. The pass was very wide and the bordering reefs were a long way away. Once we started to go with it, even at low engine power, we were traveling about nine or ten knots. That’s faster than Legacy should ever go but it got us through quickly. The water was turbulent for at least a mile out to sea as the water from the atoll poured into the ocean.
Our entry into the little bay at Toau (Anse Amyot) was completely uneventful. It turns out that the pass there can probably be entered regardless of the tide (in all but very bad weather). Since the white-water trip through the pass at Fakarava, we’ve had two similar but less severe trips through the pass at Rangiroa. It seems that this is just kind of a way of life around atolls. You plan, do your best, and then get bounced around anyway! -Rich
‘Cause Rich wouldn’t let me get the camera!
