Wednesday, August 21, 2013

Repost: The Engines of "Erebus" and Terror"

As is well-known, HMSS "Erebus" and "Terror" were both outfitted with ex-railway engines connected to screw propellors. And yet behind that general fact lies a host of detail, including slight variations between the two engines which would, without doubt, enable any searchers to distinguish the wreck of one ship from the other.

With deepest thanks to the fruits of a long-ago correspondence with British railway expert Michael R. Bailey, I thought I'd set out the basic facts, should anyone -- Parks Canada or others -- actually have the chance to recover either engine. As it happens, both were of the "Planet" type originally developed by Robert Stephenson & Co. As Michael describes it, "HMS 'Terror' had a four-coupled (0-4-0) version (strictly a 'Samson' type) built by Robert Stephenson & Co., which was used on the London & Birmingham Railway as a contractor's engine from about 1835 until sold to the Royal Navy in 1845." HMS "Erebus," on the other hand, was fitted with a 2-2-0 "Planet" (see illustration above), but not one built by Stephenson; it was rather a copy produced by the firm of Marshalls of Wednesbury for the London & Greenwich Railway in 1836. Both engines had seen about a decade of service, and were in a sense being "retired" in order to reduce older rolling stock. While they were of closely similar types, the array of the axles, as well as (Michael's note) "the variation in the height of the axleboxes" would enable them to be readily distinguished.

But what sort of shape would these engines be in after more than 160 years? Michael, whose experience is founded upon his work with "Operation Iron Horse," which involved recovering engines from an 1857 shipwreck off the coast of the Hebrides, is confident:
"The components on the 'Terror' and 'Erebus' should all be in good condition in the absence of oxygen. Wrought iron lasts well, unlike steel. The non-ferrous components should be largely unaffected. Their timber outer frames were clad on both sides by wrought iron plates. The plates should still be ok, but the timber may have gone. The condition of the ships' and locomotives will, of course, be quite dependent upon the prevailing sea conditions...... You will know well I'm sure, that iron-work etc. attracts marine life which attaches itself and builds up over the years and can distort the appearance. The main difficulty with the 'Iron Horse' expedition has been that all components have been 'buried' in a large lump of concretion (concreted crustations) and would be quite un-recognisable toa sonar scanner. The divers have had to chip away the concretion with pick to release each component, which is why it has all taken so long. However, it is likely that the crustations have been present because Scotland is on t he receiving end of the 'Gulf-stream' and is thus 'warm-water', and hence very different from King William Island."
So far, the engines have eluded all attempts at finding them. David Woodman spent a great deal of time and energy hauling a magnetometer over the seasonal ice in areas where Inuit testimony indicated one of the ships had been anchored, in hopes that either engine would produce a notable magnetic "signature" -- but all of the the targets he identified turned out to be large rocks and other natural phenomena. I don't know whether Parks Canada has or will employ similar techniques this season, but I do hope that, if they do find something, they're able to call upon the expertise of someone like Michael Bailey.

NB: Since this post, more detailed and accurate information has been developed by Peter Carney, and is given in some detail at the Building Terror blog.

5 comments:

  1. These steam engines were reported to be capable of producing only 20 and 25 horse power. It is remarkable that they were able to propel the 300 ton ships, with their bathtub shaped bows, to 4 knots. The commercially available outboard boat motors of today are probably more powerful. I wonder if and how often they were used during the voyage. I'm convinced these engines are out there somewhere. It's just a question of whether they are broken up and laying on the sea floor or if they are still on their mountings.

    There doesn't seem to be any detailed drawings and descriptions of how these engines were installed and operated onboard the ships.

    I've got "Planet steam engines" on my list of things to look up. Could they operate continuously or did they need to be stopped in order to add fresh water? How were they mounted and how did they interface with the shaft? It might not matter that these engines were nearing the end of their useful life since they only could have been run for a few days given the limited coal supply. Still, if it were me, I'd want to overhaul them as much as possible.

    Probably the wrecks will need to be found to answer all of the questions.

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  2. The Museum of Science and Industry in Manchester has a working replica of a Stephenson "Planet" -- you can even ride on the cars it pulls -- the folks there could, I am sure, tell you how much water and coal it requires to run.

    Brendan Lehane's book The Northwest Passage (Time-Life Books, 1981) has a 3-D view of one of Franklin's ships with the engine mounted in the hold, perched atop a platform made of heavy interlocking wooden beams. The wheels were removed, of course, and the drive shaft then coupled with the engine somehow. I don't know the exact source of the drawing, but it seems consistent with contemporary accounts. The NMM or the National Archives in Kew would have some additional materials.

    It's true that their output was minimal, but they were only expected to be used occasionally, either in time of calm when no wind power was available or to add some force to the forward motion of the ships when navigating through narrow channels in the ice. Their consumption of coal was large, and of water (as I understand it) enormous. They would, as William Battersby pointed out in his recent piece in the journal of the Hakluyt Society, have required fresh water from the ship's tanks, which would have had to have been distilled or made from melted ice. All in all, it's understandable why many doubted their usefulness, but Franklin, in one of his last letters, seemed satisfied that their value in certain circumstances would be considerable.

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  3. Franklin's letter -- posted to a friend at the observatory in Hobart Town, reads as follows: "The Ships have now been fitted with a locomotive Engine & screw to propel them in Calms & when the Lanes of water trend directly in the winds' Eye." This suggests the limited circumstances under which they were expected to be employed.

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  4. Do you think the "Erebus" and "Terror" had chimneys, like Shackleton's "Endurance"?

    In the PBS Nova documentation "Arctic Passage" a model of the Erebus or Terror is shown but it seems to have no chimney. That would be strange for a steam engine, wouldn't it?

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  5. Thanks for your comment, Kristina. And yes, indeed, these engines certainly had chimneys, though details as to their exact construction are hard to come by. The producers at WGBH based their computer model on an illustration I directed them to from the Time-Life book on the Northwest Passage, which offers a reasonably plausible reconstruction of how the engines were situated.

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