Sunday, July 22, 2012

Reef Passage Between Dakuniba and Viani Bay

June 12, 2012

After nearly a week at Dakuniba, the wind hadn't let up much, but we were ready to move. So we opted to take the 'inside the reef' passage to Viani Bay. Ideally, this passage should be done at low tide (so the reefs are visible) and in good light. Well, the day we did it, it was nearly high tide and cloudy.

But we had a really good Google Earth chart of the reef area we had to go through, and 2 sets of tracks from other boats. The most helpful track was one that was annotated with 'Don't go this way!'

Side note on depth-sounder issues... since we left Hawaii over a year ago, we have been having depth-sounder issues. This is a critical piece of equipment on a boat--especially a boat that likes to explore unknown waters. The sounder didn't quit altogether--that would have been fixed pretty soon. But it is getting interference from somewhere and would no longer read in deep water or very shallow water. By now it had gotten so bad that it's usable range was down to about 30 feet to 10 feet. We are not often in waters of that depth, so it just blinks and gives random readings. Dave has spent several days swapping out heads (the part of the equipment that sits in front of us in the cockpit) and troubleshooting. But we can't swap the sounding unit itself without being hauled out of the water. So we have just been doing without. (I think it's the wire between the sounding unit and the head, but Dave says it's fine).

Fortunately, in our big Rubbermaid tub of Dave's 'Future Projects', we have a spare depth sounder that was destined for the dinghy. This has been sitting waiting for appropriate bandwidth in Dave's maintenance time since Guatemala!! Obviously not a high priority. We picked up this Hummingbird 'fish finder' unit at a West Marine 'end of season' sale for only $88. It's sounding unit is a little removable tab on a bracket that you attach to the transom of a small power boat. We bought a motorcycle battery to power it. I envisioned this as a removable sounder we could use for surveying uncharted places in the dinghy before we took the big boat in.

So I've been pushing Dave to give up on his installed sounder and dig our dinghy sounder out and give it a try. The first experiment was to sit in the dinghy (with the sounder head in the cockpit) and hold the sounding part in the water. Voila, steady depth readings!!. So, for the time being, Dave duct-taped the sounder to a 6' piece of PVC pipe we had laying around, and tied the PVC pipe to the stanchion, and this is what we used for our depth sounder going through the reef. It worked fine, as long as we didn't go over 3 knots. More to follow on this saga...

I had used the Google Earth chart and the tracks from others to plot a route through the reef (several zig-zags were required), and downloaded it to the Garmin. With Dave on the bow, and me following the planned route, and Challenger following, it was pretty easy. Even on a cloudy day at high tide, Dave could see the shallow spots pretty well. And every one he pointed out, I could see on the chart anyway.

We arrived in Viani Bay about an hour later. We surveyed most of the eastern shoreline of the bay on our way in (making water, so needed to keep running the engine anyway. We were looking for a protected-from-the-wind, not-too-deep, no-coral anchorage big enough for 2 boats. There were a couple of not-too-deep spots, but we could see on the fishfinder that the bottom was full of coral. We ended up dropping anchor in a corally spot near Jack Fisher's place (where there were a couple of other boats already).
At 07/12/2012 9:15 PM (utc) our position was 16°45.03'S 179°53.17'E

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