M/Y Iron Lady

Well back to the view out the window. We managed to arrive at Fakarava on slack water and the pass treated us well.

Motoring down inside the atoll was a spectacular treat.

Reminiscent of the Bahamas, this is a lighthouse that was 90% complete and never got completed.

A dive boat headed out to do the drift dive at the North Pass.

Views off Rotoava where we anchored.

And a great sunset.

Next morning Deb and I were off to the Catholic Church. Only got a few parts of the service but the music was wonderful.

The graves are all nicely decorated as well.

More to come on Fakarava – one of our favorites.

Son George and his galfriend joined us in the Tuamotus in Fakarava. Know I am jumping ahead, but while with us at the South Pass, they spent a night at a great small resort called Tetamuna Village – very romantic. The next morning we were advised that George had proposed and Angelica had accepted.

Heard from Gel that he was shaking violently – sounds like where I was with Deb.

I proposed to Deb she said she would have to think about it. Oh well – 40 years plus later we are still together.

And all our best to son George and Angelica. I proposed in a bat infested apartment in Allentown PA as I was going to school at Lehigh and working at the American Legion off hours. Think theirs is much more memorable.

Sorry – no pictures this time but wanted to cover our plan for the Tuamtous. We arrived in Fakarava and had roughly 6 days before our son, George, and his girlfriend arrived. We decided to use the time to scope out a number of islands so that we could put together a good itinerary for them after their arrival.

We liked Fakarava but did not have time to go to the South Pass which is reputed to be remote and lovely. While we liked the town of Rotoava, it was not generally something we would have sought out but Deb had a good time and made lots of friends and we had a great meal at Havaiki.

It was then off in short order to Taou. Our nickname was Terrible Taou – something Steelers fans will get. The pass was miserable with breaking seas up to 2 miles offshore. The inside wasn’t much better and we talked to a megayacht Carry Ali who was anchored there as well. Their experience was as bad as ours. We watched the pass for 24 hours and it never got any better. We finally took our beating and left. Since Taou had been recommended, we were at a loss until someone told us that there is a false pass that does not connect with the lagoon that offers great snorkeling and a safe, but high current anchorage. Wish we had known about it but would not make an effort to go there based on our experience.

Next was Apataki where we had a good experience but the town and pass by the town are to be avoided. Safe entry is on the north end of the island and their are some wonderful beaches in this area but they are only tenable in light winds and not the SE trades. The highlight is Assam’s place and I will do a separate post on that.

From there it was back to Fakarave to meet son George. At that point, our plan of attack was Fakarave, Apataki, Rangiroa and Tikeau.

Frankly, Apataki was OK. Rangiroa was horrible – bad weather, bad anchorages and lots of wind. While other islands had much of the same, we wouldn’t go back to Rainyroa again (our nickname). As far as Tikehau, we never got there. Might be nice but we lost so much time to bad water in Rainyroa, the plans changed to head back to Fakarava.

Good move. Even better when we went to the South Pass in settled weather. Will be doing a lot more posts on this, but if I were doing FP again with just 90 days allowed on our visa, I would follow Steve Dashew’s advice to me – pick one or two spots in the Tuamotus and stay there. I agree in spades and Fakarava is our unanimous choice.

Cheers

Our Furuno Scanning Sonar has gotten a real workout in the Tuamotus. To put this in perspective, the following is a screen shot of our Furuno chart program showing Rangiroa – the largest and most populated of the Tuamotus. The lagoon is so large that the entire island of Tahiti could be placed within its confines.

Zooming in a bit on the northern bit of Rangiroa, you can see that the vast majority of the lagoon is unsurveyed with a few random soundings. You can also see our track down to Blue Lagoon on the bit that is charted. What you can’t see is that the first third of the trip is wall to wall pearl farms with random buoys every where.

This is pretty much typical of the lagoons here so eyeball navigation and the scanning sonar are the tools of choice. As a consequence, we have been refining out techniques when it comes to the use of the sonar, which I will get to in a moment, but first, a bit of a geometry lesson on exactly what the sonar shows.

I apologise for the quality of the drawing, but it is the best I could manage with the tools at hand. In the drawing, the top horizontal line represents the surface of the water and the bottom horizontal line represents the bottom. Our little boat is positioned at the top left. The angled line is the sonar beam. While the beam is actually more like a cone, for this illustration, we will consider the beam to be like a laser beam. The tilt angle of the beam can be adjusted with 0 degrees being horizontal and 90 degrees being vertical. In this case, the beam angle is something like 15 degrees. The range (how far out the beam extends) can also be adjusted so the combination of range and tilt angle determine how far down the beam sees. The gain control is used to adjust the intensity of the beam with the ideal being strong enough to give good returns but not so strong as to generate false echoes.

In our example, I have portrayed two coral heads. The black one is low lying and the red one extends almost to the surface. Considering the black one first, when the beam first encounters it an echo return is displayed on the screen. As the boat moves toward the black coral head, you can see that it reaches a point where the coral head lies below the beam and, as such, is no longer visible on the display. The way this plays out on the screen is that the return from the coral head gradually moves in on the screen as the boat approaches it. At the same time, the return becomes less intense as the boat approaches it and it finally disappears indicating that the boat will safely pass over it.

In the case of the red coral head, as the boat approaches the head, the return moves closer on the screen and actually becomes stronger. In this case, we are going to hit it and its time to alter course before doing so.

In terms of actually setting up the sonar, there are more adjustments – the first is the direction in which the beam is pointing (Training) which in most instances is pointing directly off the bow although any angle relative to the bow can be selected. The second adjustment is Sector Width which refers to the number of degrees left and right of the training direction the unit will scan. In most instances, we set this to 90 degrees although anything up to 360 degrees can be selected. The result is that the sonar is scanning 45 degrees either side of the bow which is what we really need to focus on when navigating in uncharted waters.

Other adjustments include tilt angle, the angle at which the beam is pointed down from horizontal, range, how far out we are looking, and gain which is the power of the beam. In reality there are practical limitations here. In shallower water (less the 20 meters) wee can only look out 200 meters under ideal circumstances with 120 meters being the norm. In shallow water the tilt angle must be kept low to see out far but the practical limit is around 5 degrees before reflections from the surface degrade the image.

Historically, I have always set the tilt angle so I could clearly see the bottom reflection like the image below. When using the sonar for long periods of time, however, this complicates interpretation of the image as one is always examining changes in the image that in reality have no real impact on safety.

We have therefore shifted to a new strategy where I do not tilt the beam down far enough to return a bottom image. Point being, we are only concerned about objects that raise to the level of a threat for impact. As such, I can safely forget about anything more then 10 meters deep and concentrate only on objects which are shallower then this. The result of this strategy is a blank screen most of the time which requires no interpretation. Objects which do result in returns are monitored to see if they are increasing in intensity or decreasing in intensity as the boat approaches. Like our simple drawing above, objects which slowly disappear as we approach them are safely ignored while those that don’t are given a wide berth. To aid with safety distances, I set a range ring that defines the distance at which we will initiate a course change if an object appears inside the ring.

When anchoring, we set the sonar in a 360 degree scan mode around the boat to look for obstructions. In the image below, you can see a three coral heads between 9 and 11 o’clock but they are well outside the range ring of 46 meters which represents our swing radius.

For the technically inclined, we have found that using short pulse length and max gain give us the best results. To insure that I have the gain set correctly, I will occasionally tilt the beam down until I get a solid bottom return and adjust the gain accordingly and then return to my shallower tilt angle. If objects do appear to be problematic, I have one of the user defined buttons set to vertical mode and when the beam sweeps over an object of concern, pushing the button does a vertical scan in that direction so I can can get a good approximation of the actual depth of the object.

After the Society Islands, our next ports of call are the Tuamotus. From Bora Bora to our first stop in Fakarava some 330 nautical away (1.5 days at our normal cruise).

The Tuamotu archipelago consists of roughly 78 islands scattered over a 950 mile area roughly east of the Society Islands lying in a northwest to southeast direction. Only 1/2 of the archipelago is inhabited and the total population in 2007 was roughly 17,000 people centered mainly in Rangiroa.

Nuclear tests were conducted by the French on Fangataufa and Mururoa and entry into this area is prohibited.

Our travels took us to the northwestern most atolls between Fakarava and Tikehau including Rangiroa, Taou, and Apataki.

As a group, most of the Tuamotus are low lying coral atolls with lagoons ringed by reef and islets. As such, the Tuamotus are visible to the naked eye only around 3 or 4 miles out. The highest points are generally the palm trees at 50 feet. Generally, the lagoons are only accessible by one or two passes. To quote the Admiralty Sailing Directions, “The whole archipelago requires great care. Most atolls are low lying; the reefs that surround them are dangerous; there are few navigational lights and currents are uncertain.” and “Navigation of passes through reefs into lagoons also require care.” That is an understatement. For a more complete look at the nature of conditions in the passes, you can refer back to my first post on Maupiti as the dynamics are the same in spades. There is usually a race with whirlpools, eddies, and exceptionally heavy seas with standing breaking waves – in some cases this disturbed area extends up to two miles off the pass.

All this is complicated by different portrayals of the nature of each pass in the various guides we use – there is little consistency or agreement between them with one portraying a pass as safe and another portraying it as dangerous. In general, we have come to rely more on the “Admiralty Sailing Directions” as our principal guide as it seems more matter of fact and reliable.

All of this is further complicated by trying to estimate the time of slack water which is the most favourable time to enter or exit a pass. Times for slack water do not correspond to high and low tides and the variances can be as much as 5 hours. Like Maupiti, the lagoons fill with prodigious amounts of water as waves break over the reefs and the exit point for all that water are the few passes or breaks in the reef. This generates prodigious outgoing currents of as much as 8 knots for most of the day with brief periods of slack and incoming. It is pretty much a constant discussion among cruisers about the best way to determine slack water and nobody seems to have a good handle on it. The “Admiralty Sailing Directions” suggests that it can be timed to hours after and before moon rise and moonset but also notes that wind, seas and other factors can alter this by a wide margin. Added to this is the additional complexity of trying to time passages between atolls to make favorable departures and landfalls that correspond to safe times to transit the passes at either end.

As if this were not enough, many of the interior portions of the lagoons are not surveyed so eyeball navigation with good light behind you between 1000 and 1600 hours is the rule (along with our scanning sonar which is seeing a lot of use). Night time travel either in the lagoons or thru the passes is just plain foolhardy even with a solid prior track – danger lurks less than a boat length away in many cases.

Having said that, the Tuamotus were wonderful and worth the sphincter tightening effort to see them. As we near the end of our time in the Tuamotus, though, I am truly looking forward to the more navigationally mundane Marquesas.