Wednesday, March 18, 2015

Ice Diving on HMS "Erebus"

Ice-diving HMS "Breadalbane" © 2014 DND-MDN Canada
In just a few weeks, divers will return to HMS "Erebus" for a series of dives under the ice, opening a new and promising chapter in the Franklin search. Last fall's dives were severely limited by poor weather and the approach of new-formed ice; now, the very things that were disadvantages then will be advantages. Having a stable, secure platform on which to place equipment and support teams will enable a robust schedule of dives, and no surface weather will interfere. Beyond that, as lead archaeologist Ryan Harris has noted, the water under the ice, protected from surface winds and turbulence, will be calmer, and visibility better.

So what can we expect? A thorough survey of the ship, for one; using lasers, a precise map of the vessel and the surrounding debris can be assembled in three dimensions. We'll know the nature and extent of damage to the vessel, the location of the ships' anchors (which may give us clues as to whether the ship was piloted to this location and deliberately anchored, or drifted), and it's quite possible that additional artifacts in the debris field will be identified and mapped. The dives aren't planned for artifact recovery, but it's possible that, if something is found in plain view and it's already been mapped and photographed, it could be brought to the surface for study and conservation. I would not expect, though, that there will be any attempt to enter deep inside the vessel itself, although a ROV might go in to take some images and measurements. The stability of the vessel will need careful study before divers can enter, and a safe route and protocol established -- so this will likely wait until the late summer dive season.

I'll be particularly interested in the anchors -- were they deliberately deployed? If they were, that would be a key confirmation of Inuit testimony that they saw fresh tracks and deck sweepings near the vessel, and that it was manned when it arrived. And, if it was -- as Ryan Harris recently observed -- then we may have to re-assess Franklin's achievement: reaching the point it did means that the vessel passed Cape Herschel and entered an area already charted by Dease and Simpson -- effectively linking the eastern and western surveys and traversing the last link in the Northwest Passage.

3 comments:

  1. Do we know if they will have a website for up-to-date (within reason, of course, as they are in the artic in April!) reports of the investigation or is this going to be a "we'll get to you once we're good and ready so don't hold your breath" shindig?

    I ask since I am sure that once information starts coming in all Franklin enthusiasts will be debating what this or that discovery means with great gusto!

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  2. Alan, thanks for your comment. Parks does have a fresh blog-style website, cleverly titled "Frostbits," which has been updated several times in the past week or so, with each update posted to Twitter with the #FranklinExpedition hashtag. Let's hope they keep updating us!

    There's also a great online interview with Marc-André Bernier in which he gives a pretty detailed account of what they hope to accomplish with these ice dives, over at Archaeology Hour.

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    1. Thanks for the link, especially to the Archaeology Hour page. The image of the Erebus is different than the ones I've seen before and it really suggests that the damage to the bow is more serious than it originally seemed. It also may indicate that the decks have collapsed on top of each other to some extent. If so it may make investigation less a matter of searching and more one of salvage since you might have to remove a lot of debris to get at the heart of the ship. Here's hoping it's not that bad.

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