Research vessel setting off for Nikumaroro (Gardner Island)

On the Way

                                                                    Photo by Pat Webb R/V Ka’Imikai-O-Kanaloa, Honolulu  

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The underwater Tighar search at Gardner Island (Nikumaroro) has failed. 

The below are quotations from the Tighar Website concerning their recent underwater search at  Gardner Island and the futility of continuing with the search. The airplane isn't there, there are no parts to recover, and they almost lost a very expensive AUV prowling around in the coral that surrounds Gardner Island. 
 The original search was scheduled to run for 10 days from June 29, 2012; however, 5 days into the search the Hawaiian expedition ship R/V Ka’Imikai-O-Kanaloa ( KOK) set sail for Honolulu and abruptly ended the expedition. With practically no leads and dangerous coral surrounding Gardner Island, the Captain of the ship evidently refused to send his ROV and AUV into harms way. Once the search was underway the robotic vessels found nothing but coral and caves dug into the sides of a cliff. To make matters worse, the AUV wedged itself into one of the narrow caves and was almost lost to the sea. The Tighar website states: "Operating literally at the end of our tether, we searched for over an hour in nightmare terrain: a vertical cliff face pockmarked with caves and covered with fern-like marine growth. We finally came across the AUV wedged cross-wise (parallel parked) in a narrow cave. Wolfgang flew in and used the claw to gently grab a handle near the stern of the fish. He then pulled the AUV out of the cave and well clear of the cliff face before releasing it to float to the surface."
 
  

BLUEFIN 9 SILOBluefin AUV

There was also trouble with the ROV in the search area. To quote Ric Gillespie of Tighar: "Immediately offshore the reef edge in the primary search area the reef slope drops away in an essentially vertical cliff hundreds of feet tall. Coral outcroppings on the steep slope tend to snare the ROV tether, forcing the pilot to back-track to free the snare. Further out and deeper, the slope moderates somewhat. Except for some Norwich City debris, no man-made objects were seen in two 60-foot search swaths from 21 meters (70 feet) down to 365 meters (1,200 feet). There are, however, many flat coral surfaces with right angle corners resulting in numerous false alarms.
 

A science ROV being retrieved by a research vessel

There was no airplane or airplane parts found in the search. The only findings were debris from the wreck of the Norwich City, a freighter that impaled itself on the reefs of Nikumaroro. On board the research vessel was Dr. Bob Ballard who discovered the wreck of the luxury liner Titanic, Discovery Channel Executive Producer Brooke Runnette, and Alexander “Sandy” Shor, Associate Dean of the University of Hawaii School of Ocean and Earth Science and Technology.  

02:00Z 7-19 (16:00 7-18 KOK) R/V Ka’Imikai-O-Kanaloa

Launched ROV to continue mowing the lawn in the primary search area.

04:00Z 7-19 (18:30 7-18 KOK)

Recovered ROV after completing two lines – 1,200 to 600 feet. We only go up the hill because it’s hard to see the surface going downhill. We are not searching the vertical cliff that goes from 600 ft up to 250 feet.

06:00Z 7-19 (20:00 7-18 KOK)

Launched AUV for all-night mission to re-survey the primary search area and collect side-scan data south of Norwich City.


After discussion and analysis of the results so far, they have decided that there is very little point in extending the trip. The problem is the nature of the reef slope: a vertical cliff from 110 feet down to 250 feet, with a shelf that runs along that contour from Nessie to Norwich City. The airplane could have come to rest there briefly and lost pieces, but they have not found anything at all on that ledge.

From there the cliff goes almost vertically down to 1,000 – 1,200 feet, with another ledge. They will spend the rest of today searching that area. That is where the Norwich City wreckage came to rest, so maybe that's where the airplane stopped.

But the question of searching for an airplane in this environment is even more basic than “what ledge” or “how far down.” Given what we now know about this place, is it reasonable to think that an airplane which sank here 75 years ago is findable? The environment is incredibly difficult, with nooks and crannies and caves and projections; it would be easy to go over and over and over the same territory for weeks and still not really cover it all. The aircraft could have floated away, as well.

So for the time they have left, they will focus on the ledges. Nothing could stick to the cliff walls, they are far too steep for anything to stick; and besides, if you get something (like a tether) caught, you can cause an avalanche (they did) and lose your ROV (they almost did).

We have collected an enormous amount of data. We won’t know exactly how much, or what it all means, until it’s integrated and analyzed, but it is certainly of great value, not only to us but to anyone doing ocean and reef research in the area. We have no idea what might be discovered as we pull together all the pieces without the fog of war to distract us.

They head for Honolulu tomorrow.

Yesterday’s rescue of the AUV involved hard throttle usage keeping the ship in position, and that caused a propulsion system failure that took six hours to repair. The afternoon was lost for searching, so Ric and TIGHAR cameraman Mark Smith went with the ship’s bosun in the skiff to check landing channel conditions. They found it to be in mid-tide on a rising tide with a moderate swell – not great landing conditions but acceptable. Roughly 25 people availed themselves of the opportunity to go ashore.

By 04:30Z 18 Jul (18:30 17 Jul KOK) all the tourists were back aboard safely. Everyone was impressed with the island’s beauty. This was a good break from the tension of underwater operations.

The ship’s propulsion system problems were repaired and were tested during the night. ROV search operations were resumed at 08:00 (KOK) with a dive to locate and examine the promising target we couldn’t find yesterday. Analysis of the 17th’s AUV side-scan data showed yet another “strong Category 2” target in a different location.

The second target turned out to be a large coral boulder; everything with the AUV’s sonar turns on the exact angle as it flies past, and it’s tough to program in repeated passes when you don’t know what’s there or what might be there. In fact, the AUV did not see any of the Norwich City wreckage on the first several passes – it required a completely different angle and approach and suddenly the great mass of crumbling steel appeared.

The other target, after much work and discussion, was finally decided to be a piece of the Norwich City’s keel, much degraded and skeletonized. Now they are going back to the “mowing the lawn” approach, a visual search which is more discriminating and more accurate at acquiring targets than the side-scan in this environment. The hope is that they will pick up a debris field and be able to follow a trail, as it were – much like was done to find the Titanic. But it is, of course, possible that the aircraft floated for some time and drifted out to sea. If that is the case, it is not too likely that any small parts will be found. But they are far from done, and the possibility of extending the trip for one or two days to compensate for the lost time due to equipment problems is also being discussed.

14:00Z (04:00 KOK)

The AUV finished the search box south of Norwich City. It covered the area almost to the landing channel and returned to the surface for re-programming for the next mission. Unfortunately, Phoenix was unable to communicate with the AUV for re-programming. The AUV was too close to the reef for KOK to execute a recovery. The Captain mustered all hands and launched the skiff to secure the AUV and bring it out far enough from the reef for KOK to do the recovery. The AUV was successfully recovered. The Captain was less than thrilled.

18:00Z (08:00 KOK)

We amended the ROV search technique for more efficient use of remaining time. “Mowing the lawn” by running lines west to east up the reef face from 368 meters (1200 feet) to 61 meters (200 feet) wastes time because most of the slope is too steep for anything to rest on. Better to search north to south at depths where the reef slope is mild enough for wreckage to stop descending.

18:30Z (08:30 KOK)

We launched the ROV for a surface test run and the camera crew filmed it from the skiff.

20:30Z (10:30 KOK)

We launched the ROV for detailed inspections of intermittent ledges and “catchment” areas at the base of the first cliff – depth 61 to 91 meters (200 to 300 feet) – from Nessie south to Norwich City.

23:30Z (13:30 KOK)

The ROV was recovered. Terrain in the area covered was uneven and strewn with large coral boulders. The base of the cliff was undercut in several places forming large shallow caves. Ledges at the base of the cliff vary in width to a maximum of 30 meters (100 feet). There are many coral plates with square edges, and numerous false targets. No man-made objects were seen. Beyond the ledge, the reef slope drops at an estimated angle of 50° to 70°. In some areas, such as at the main Norwich City wreckage site, the slope moderates somewhat at depth of 305 meters (1,000 feet).

00:00Z 20 Jul (14:00 KOK)

The AUV data from last night has been processed. No targets of interest detected.

01:30Z 20 Jul (15:30 KOK)

We launched the ROV for an inspection of the reef slope from Nessie south to Norwich City at the 305 meter (1,000 feet) depth.

03:19Z 20 Jul (17:19 KOK)

Recovered ROV. There is very little moderation in slope steepness along the line until the vicinity of Norwich City wreckage. Many coral plates with square edges. Numerous false targets. There was a fishnet/rope tangle on the slope face at 900 feet at 274 meters just north of the Norwich City wreck.

06:00Z 7-20 (20:00 KOK)

KOK collected SeaBeam mapping data off the southern side of the island to fill gaps in the data collected earlier. When that is complete we’ll begin the voyage back to Honolulu.

We headed northward at midnight our time (10:00Z, 06:00 EDT). At 19:40Z we were at 3° 23′ S, 173° 47′ W making 9.1 knots.