Archaeology in The Hunley

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rchaeology is a science with a set of standard methods and techniques and an art that draws on the experience and knowledge of the archaeologist to interpret what the process reveals.  It requires careful and meticulous recording of the context of finds because in its most usual form excavation is destructive. 

Understanding Archaeology

†††† It will help to summarize the archaeological process before going on to the Hunley excavation particulars.  I can't overemphasize the importance of accurate recording of context for all artifacts and features discovered.  Every project is a little different in detail but all do this one way or another.   I'm not an archaeologist, but for well over a decade I've participated in and contributed to numerous archaeological projects.  Iíve drawn on this more than six months of hands-on field experience to provide the background and explanation on this page. 
     Excavation proceeds at a preplanned pace.† That is, fill is removed a little at a time over a predefined area.  At any time, no place within that area will have been excavated much deeper than any other.  When an artifact (or feature) is discovered, it is not removed immediately, but the fill in the entire area around it is lowered to free it.  For some projects only major finds are recorded individually, but itís likely that everything was treated this way on the Hunley.  The find is assigned an identification code that will be used to track all information about the item in the project database.  The information includes the exact X, Y, and Z position of the item, including what part of the item the coordinates refer to, the item's size, and if relevant, its orientation.  A narrative description is written, including condition, distinguishing details, and identification if known.  Before the item is removed from context photographs and possibly drawings are made.  The context itself is described, including the archaeological layer in which the item was found - this layer has its own description in the database. When the artifact is removed, it is tagged with its identification code.
     Often it isn't possible or convenient to excavate something in situ.  In this case what we can think of as a super-object is defined.  On the Hunley, these were called "block lifts".  The block lift is treated as just another artifact and documented in the same way.  Later on the block lift itself is mini-excavated using the same process described above.  Since the context of the lift was recorded, the context of everything found in the lift can be transferred back to the overall context.
     After removal, artifacts are cleaned to aide in further identification and the description is augmented as appropriate.  Cleaning might be as simple as washing sediment away or as complex as applying special conservation techniques.  On the Hunley project, block lifts and often other items were x-rayed. Since many artifacts were heavily concreted or contained other artifacts, this aided identification or guided further mini-excavation.
     Like all science the results of an important archaeological project are published formally for peer review of the conclusions.  Proper technique and complete documentation are essential for evaluation and acceptance of the results.


This page is organized chronologically. 
Scroll to the bottom or click for the latest update.

Season I
     We had the opportunity to follow along as the archaeologists went deeper and deeper in the dense sediment filling the Hunley, but we had to make do with limited, low resolution web cam views, very few photographs, and tantalizing but terse regular news reports of findings.  Having participated in many archaeological projects as a volunteer, my intent on this page is to draw on that experience to interpret the reports and try to reproduce the experience for the many interested observers.  Remember this is my interpretation and subject to gross error.  Likewise the speculation is mine, based on the same reports available to all.  Nonetheless I hope everyone enjoys the material presented here.  I certainly enjoyed the vicarious archaeology I used in creating this page and I was pleased in studying the few photos to discover several features before their formal announcement.
The reconstruction showing the plates removed for excavation
     The schematic rendering at left, using an early version of my Hunley reconstruction, shows the locations of the three semi-cylindrical plates removed in preparation for excavation. The cabin was completely filled with sediment.  
 
     The rendering at right shows the crew cabin ready for excavation.  Notice the narrow metal parts in the exposed hull area.  These proved to be substantial elements of the internal cabin frame. 

The reconstruction before excavation

     Estimating the distance between the rings, I found that if there were others between the visible pairs, they would be spaced about every two feet. My first confirmation was finding one disguised by concretion at the aft edge of the center opening.  Web cam views and released interior photos later confirmed the positions of the hidden interior frame components. 
     William Alexanderís
interior drawing shows braces for the steering rods set high in the hull.  The excavation of the aft ballast tank uncovered the steering lines enclosed within a tube running through the top of the tank.  I expected to see something associated with the steering mechanism near the top of the cabin.  A Post and Courier article indicated the archaeologists were surprised not to find it.  Simon Lake's drawing, the only one to show the deadlights, places the steering lines along the sides of the cabin.  Such lines could have been hidden by the concretion.  A later report described tubes that might be associated with the rudder control under the crew's bench, and this was re-iterated near the end of the second excavation session.

     The illustration on the right shows the initial excavation at the center panel opening.   The web cams showed good excavation practice with clean level surfaces and right angles, reflected in the graphics here.  The vertical sections expose the sediment layers for documentation and analysis.


     There appear to be similar bracket-like structures on three visible rings (below).  I thought these similarly located structures might be associated with the steering mechanism.  The reports never mentioned them and their actual purpose remains a small mystery.  Perhaps they are merely joints on the interior frame members.

Early central panel excavation

Central panel excavation progress      My excavation graphics,  based on web cam views with the hull openings partially obscured, are very much guesswork on my part.   I hope they give a flavor of the activity and progress of the excavation.  Please don't depend on them for accuracy.
     The drawing at left shows my impression of the early excavation in the cabin area amidships.   Remember that these are schematic simplifications.  The surface of the sediment fill appears much more uniform than it really was and I've left out small features that weren't clear enough for me to interpret.   

 

The Hunley is leaning about 45 degrees to starboard.  The reconstruction leans at this angle for the excavation graphics.

Click for the answer. Which way is up?  Click for an answer to this and for a mini-primer popup on archaeological context.

Center panel area with crank visible.

     The rendering at right shows the midships area at the end of the fifth week.  The crank mount visible in the illustration is much more identifiable than in the web cam view.  The concretion makes the structure an almost shapeless mass and the mount is nearly invisible.  Interpreting that view I thought the handle extensions angled away from the mount as shown so that the handle is narrower away from the axis.  Later images confirmed this interpretation.  

 

     The first of human remains, discovered in the snorkel box part of the crew compartment at a higher level than expected, appeared to be partly articulated, that is, with bones organized more or less as a skeleton.   Articulated remains provide more insight into the last moments of the crew.  Until then, the archaeologists had thought all the bones would be found disorganized on or near the cabin floor.
     The crewman's body was thought to have been floating near the top of the cabin while silt filtered in below.  The bodies of the crew back in the cabin may have been held down by parts of the crank, or silting may have been slower, resulting in remains near the cabin bottom.  Mayan burials we excavated in Belize (see below) were interred seated with drawn up knees.  The skeletons collapsed into a very small area, still nearly articulated.
     Excavation of the Hunley crew's remains proceeded slowly.  In typical archaeological practice, bones are carefully exposed using small tools with the intent of revealing as many as possible without disturbing their position.  If this requires going lower in the sediment, a "plinth" or pedestal of unexcavated fill may be retained under the higher bones to support them.  When excavation has proceeded as far as possible, the positions of the bones are carefully recorded with measurements, drawings, and photographs.  Only then are the remains removed.  Itís not particularly clear, but the third photograph on my Laguna de On page (link opens in a new window) shows such excavation of a "seated, flexed" Mayan burial. Using this careful technique helps identify individuals, especially if more than one are in close proximity.  Forensic analysis may indicate something about the way the Hunley was operated, and could tell something of the circumstances of death.
     By the beginning of May 2000 partial remains of eight crewmen were reported uncovered more or less at their work stations.  The remains of the commander were announced toward the end of the month, apparently seated at his station under the forward hatch.  Early in the second session the total complement was revised to eight.
The positions and distribution of the crew's remains will play an important part in determining the last moments of the Hunley, but official policy limits the availability of this information.  Click here to read my thoughts about this.

Click for my thoughts on the remains.

 
The excavation near the end of the third week.      My interpretation of the extent of the excavation near the end of the third week is at left.   As before, the illustration is simplified, and includes speculation on my part.

Excavation proceeded slowly in the forward area because of the crewman's skeleton and the concreted mechanics associated with the diving planes and an unexpected air pump. 

Different levels of fill The illustration at left, a cross-section looking forward, shows the fill remaining in several areas as it may have appeared during the third week.  The extent of excavation varies from area to area.  The pictures above show that it is relatively easy to excavate the open areas, but more difficult under the plates between the openings.  An important unexcavated area was under the snorkel box and the forward hatch, Lt. Dixon's station.

     There were things besides artifacts I looked for as excavation continued.  The early accounts say the hull was made by cutting a cylindrical steam boiler in half lengthwise and adding expansion strakes on the sides to increase the height.  If this is accurate, I expected the rivet back plates to be semi-cylindrical, just like hull plates, and not to extend the full circumference.  At least one photo seemed to show the latter. 

     This rendering provides an interior view looking forward from the aft opening.  The released interior photos showed heavy concretion masking details I've speculated here.   The wooden bench is visible close to the sediment surface on the left side of the image.  I presented it as a single board in the graphic, but wondered if there were individual seats.  The bench appeared to be inclined about 45o, making it actually horizontal if the Hunley were on an even keel.
     Excavating in sections to expose vertical profiles as shown here is standard archaeological practice.
Inside, looking forward.
    Archaeologist Mike Scafuri found the first crew artifacts, two very well-preserved buttons, on the bench in the opening amidships.    Here's one of the things I find so exciting about archaeology:
Using manufacturer's marks on the backs of the buttons, the Post and Courier identified the buttons as possibly coming from the coat of crewman Cpl. C.F. Carlson.  One can never be certain, but imagine the science, and art, that might tell us where an individual sat on that historic mission 137 years ago.  You can read the newspaper report via the Post and Courier link on my main Hunley page.

     The later discovery of a Union soldier's identification tag caused a stir, and showed the close relationship between archaeology and history.  Searching historical records uncovered a possible link between this soldier and the Hunley, but didn't resolve the questions raised by the find.   

Whenever we interpret historical records or events, it's important to not to impose our own cultural and social biases on them.  In archaeology and history, understanding the context of the study is essential

     Removal of fill aft uncovered what seem to be controls for the ballast tank in the area under the aft hatch.  Alexander's drawings show the sea-cock for filling the aft tank centered on the port side in this area.  Chapman's painting shows what could be the inlet for this valve, maybe a third of the way up the hull in about the same place.
     The hatches are attached to the hull where it begins to taper, additions to the original cylindrical boiler parts.  The aft panel opening adjoins its tapered section, but the forward opening is separated from its section by the panel with the snorkel box.  Heavy interior concretion, not illustrated at all above, made it difficult to reach the area under the hatch and the forward bulkhead. 
     As excavation went deeper it proceeded more slowly.  The clay fill was more densely packed, and discovery of remains and artifacts necessitated delays for very important context recording and documentation.  Uncovering of very fragile fabric artifacts especially slowed the process.
     There wasn't much photographic information available late in the excavation and although the web cams provided tantalizing views, they showed only a very limited area.  The textual reports though were rich and I've tried to address a little of that in my interpretation.  Excavation had progressed much less in the forward area, because of many features, artifacts and remains.  
     A large bellows device, apparently associated with the snorkel, further slowed access to the forward hatch area.

 

The excavation at the end of five weeks.
The crank in the forward excavation area.      These two renderings approximate photos showing the most forward part of the crank.  Notice the considerable fill remaining in the next forward section under the snorkel box, in part because of the bellows discovered there. 

Looking forward from the center area.

The end of the crank.      These speculative renderings show the same area with the fill taken down along the edge of the bellows to the point where it became clear that the crank does not extend to that section.  I've shown a rectangular bellows, although two boards connected at a pivot is more likely.  Since the descriptions are too general to place anything, I've left out other parts of the mechanism. 
     At first I thought the bellows might be foot pumped but now I think hand operation is more likely.  See my reconstruction page for more speculation about the bellows.  

Looking forward toward the bellows.

     After attempting to remove the bellows, a next to impossible task if my speculation about its attachment were half true, the Hunley team returned to one of their earlier plans for accessing the forward area and removed the plate with the snorkel box.  Having excavated the area some, it must have been easier to disconnect the snorkel mechanics. 
Conceptual view after removal of snorkel box plate.      The highly speculative rendering at left show the forward cabin after removal of the plate.  The low resolution overall web cam view showed the rivet plate between the sections, the adjacent frame ring about where I expected it, and considerable fill remaining at the forward end.  The bellows was very difficult to make out in the view. 
     The work area cam provided a field of view similar to this, but cut off at the bottom.  The interior it showed soon after removal of the plate was much more confused than my rendering.  More fill had been removed under the forward hatch plate, revealing a jumble on the port side.  The dive plane axle was visible just aft of that.  The bellows apparatus was another difficult-to-interpret jumble with what appeared to be some sort of structure just forward of it.  The frame ring was obvious just forward of the rivet plate, but the next ring, still in the fill in the graphics above, was not obvious.  Based on the number of rivet holes, the removed plate turned out to be larger than I'd estimated, necessitating changes to my reconstruction.
     The rendering at right, which approximates the photo taken when archaeologist Maria Jacobson discovered Lt. Dixon's gold coin, presents my guess of the extent of excavation when work was suspended for the summer.  The axle joining the dive planes runs from top to bottom on the right, with what I thought was the control lever attached near the top and projecting into the commander's station.  The image includes an approximation of what I saw as the ballast tank pump, with its handle going back over the axle and just touching the last crank mount.  The last crank handle is visible on the left.  Except for under the bench, the second crew station is shown clear of fill, but I've left some in the forward stations. Crew station 1, from the starboard side.
     The speculative pump top and pump handle are clearly visible in the web cam view, approximated at left.  The diving plane axle is also visible but my placement of the control handle remained speculative.  This position was confirmed in later photos and reports.  I included a frame ring forward of the pump, although it wasn't clear it actually exists.  Later photos appear to show a ring that is much smaller on top than on the sides, perhaps to facilitate crew movement.

The rendering below gives a view I was waiting for.  I placed the camera just under the hull plate and pointed it forward.

     The bench, with fill remaining below it, is on the left.  The dive plane axle runs diagonally across the cabin forward, with the speculative ballast tank pump forward of it on the starboard side.  The forward bulkhead is hidden by fill in the front part of the commander's station.  Again, I've guessed there is some fill remaining on the floor of the forward stations.
     (This camera view was provided to lab visitors during the summer, but never released to the public.)
Interior view, looking forward.
     The view at left approximates an underwater photo published by the Post and Courier in June 2001.  It shows a possible control rod or air pipe under the bench, but not some of the large featureless concretion masses also visible in the photo.  The sediment remaining on the floor is also speculative.
Scematic of remaining fill.      Excavation was suspended for the summer before all the fill was removed.  According to the report, a foot of fill remained against the fore and aft bulkheads, although this was underestimated.  The schematic at left, from the port side, shows this and the fill left under the crew's bench, although it's likely some of that had been removed.  The report also said the forward hatch had not been excavated.  The inset shows how fill could remain supported by the side of the hatch, even if half of the commander's station has been excavated.  (The web cam showed a new brace under the hatch, probably to support the sediment above.)  The schematic shows fill on the floor of the forward stations, although this may have been removed in uncovering the crew's remains.
     The reports did not say all remains were recovered and my speculation that some remained in the commander's station was later confirmed.
     Why retain these foot-thick plugs of sediment at the ends of the sub?   One reason might have been to protect the controls on or near the bulkheads.  Alexander's drawing shows ballast tank fill valves on both bulkheads, and a manometer, compass, and steering control at the forward.  Leaving them in the protective sediment over the summer would prevent deterioration.
     The Friends of the Hunley reported also that a geologist will study the sediment stratification at both ends of the cabin.  As sand and other marine material filtered into hull over time, it settled to the bottom in layers that remain today.  The geologist would look for physical, chemical, and micro-content variations in the fill to identify layers, as illustrated in the exaggerated image at right.  These layers represent a time sequence with the oldest layers at the bottom.  They might even show if the Hunley listed slowly after it sank, or settled that way immediately.  The sequence mapped on the forward plug can be compared with that on the aft and with similar information recorded as sediment was removed over the months of excavation.  Eventually, a three-dimensional map can be produced, showing just how the hull filled. (See the Sediment Analysis note below for more information.)

Example illustration of stratification.

     The time sequence was centuries rather than decades, but see my photo of geo-chronologist Tom Stafford performing just such mapping in an eight-foot deep trench in Belize on my Laguna de On page (link opens in a new window).

Season II
     The project resumed with about of week of x-raying in October 2001.  By mid-October new excavation was revealing more of the Hunley
The aft hatch area.      The impression at left shows the rear hatch area at the end of the first week of the new excavation season.  The features appear much clearer in the rendering than they actually did on the submarine.  In reality many details were obscured by heavy concretion and the difference between the fill and the features was less obvious.  Much of what is depicted here is my own interpretation.  Reports describe a flywheel and  what is probably a chain connecting a gear on the crankshaft with one on the propeller shaft.  The rendering includes a highly speculative interpretation of the aft ballast tank pump.

      Bench support brackets and attachment fixtures for the keel ballast were reported at the end of the second week, but no photos were available.  The bench was revealed to have three sections.

     By the end of the third week of excavation the archaeologists reached the aft bulkhead, which was further aft and surprisingly shorter than expected.  Numerous details of the construction were uncovered including pump and valve connections but few photos were available to aid my interpretation.  A rectangular mechanism that may be associated with the steering control was not reported but appeared in one of the photos.  It's depicted at right just behind the flywheel.

Aft hatch area after three weeks.

Highly speculative forward hatch area.

     After four weeks, nearly the entire crew section was excavated.  Recent confusion about the remains uncovered was resolved: the Hunley held a crew of eight, including the captain.  Since there are seven cranking stations, this raised doubts in my mind about the importance of the air pump and snorkel.  Lacking dependable information about the location and distribution of the remains, I'm now inclined to accept historical accounts that the snorkel was ineffective and not used.
     The excavation reached the forward bulkhead, uncovering some of the equipment expected to located there, including a compass box.  Ballast tank piping and several levers were uncovered, including a tiller.

     The wooden box containing the compass was x-rayed during the fifth week and efforts to remove it began.  The box sat on a wood shelf that appeared to be attached to the forward bulkhead.  Press reports said the compass had come loose within the box and was concreted to the hull.  A photo provided the press suggested the compass body might have been lying on its side fore and aft in the box.  This position could have resulted if the compass floated free when the cabin filled with water.  I wondered if a steep dive might have caused it.  The box is of tongue and groove construction, with a slide-off top that is not attached.  
     The most recent reports made no mention of the other controls in the forward section and my crude rendering at right remained highly speculative.  I have speculated that the cylindrical object rendered as metal just left of the box could be a mounting bracket, or a soft iron compass corrector to compensate for the iron hull, or might even be a candle (but see below for its actual function).

An interpretation of the compass

     The compass, or at least its box, was removed during the sixth week, but more importantly, the most recent reports finally described the side-to-side tiller pictured above.  It is connected to mechanics of some sort under the bench and eventually to a mechanism that runs over the aft bulkhead.
     Other findings include a tool and what appear to be spare parts for the propeller drive.  These new items provide an interesting look into the operation of the Hunley.

     Excavation of the cabin was reported complete about this time and, as the archaeologists and conservators turned to artifacts and remains that had been block-lifted, that is removed within blocks of sediment, further reports from the Friends unfortunately ceased.


     During the early 2002 excavation hiatus the underwater web cam, mounted in the cabin looking forward from about the fifth crew position, gave a reasonably unobstructed, if murky, view of the forward hatch area.  Close examination of the view suggested two things to me:

o

The feature in the center of the shelf, next to the compass, extends to the cabin ceiling, making it a foot and a half long.  In a March presentation at the Smithsonian in Washington DC, Maria Jacobsen revealed that this is actually part of the hatch latching mechanism, indicating that the forward hatch was not latched, perhaps an interesting clue in solving the mystery of the Hunley's loss. 
o The top part of the tiller was clearly visible in the web cam view.  Much less visible was the lower part, possibly coming close to the end of the steering rod on the floor, which was clearly visible.  The rod is not actually under the bench, but appears to be angled closer to the centerline forward.  The view is too dark to draw a definite conclusion, but the tiller may be connected directly to the rod rather than by a more complex crank linkage.

Sediment Analysis
    Some of Maria Jacobsen's remarks at the Smithsonian seminar provide at qualitative view of the sediment analysis mentioned above.  The lower part of the cabin was filled with very fine sediment that was deeper at the forward end.  Although all the remains were in very good condition, Lt. Dixon's were especially well preserved, indicating he was covered by the protective sediment sooner.  The fine sediment indicates there was no large breach in the hull, but that the water came in relatively slowly through an opening or openings small enough to keep coarse material out.  The upper layers on the other hand consisted of much coarser sediment, including relatively large shells.  This material would have entered the hull through larger openings, like the three we find in the hull today.  
     This information indicates there was no catastrophic damage to the hull during or following the attack on the Housatonic and suggests she did not sink outright, although she may have suffered from slow leaks.  The major hull damage seen on the Hunley occurred some time after the historical events and was not a consequence of the attack or pertinent to her loss.  Considered with the locations and attitudes of the crew remains, this information tends to support a loss-of-oxygen scenario over outright drowning, although the co-mingling of remains near the pump stations is evidence for leaking.

     You can read a summary of the Hunley sediment analysis on the Geological Society of America web site at this link.

 

Artifacts and Archaeology

The popular impression of archaeology, embodied in the Indiana Jones character, is that its purpose is the recovery of artifacts.  In reality, the context of the artifacts is much more important than the artifacts themselves, because that's what reveals the history.  The regular reports about the excavation list the discovery of artifacts and mention the difficulty of recovery, but don't relate the importance of the archaeological context.  The discovery of a pipe in the Hunley is interesting, but the discovery of a particular individual's pipe, carried in the pocket of his jacket, is significant in telling us about that man.  What the reports don't tell us is the archaeologists' careful recording of this context to eventually compose this story.  That's why it's taken months of excavation to get this far.  Read between the lines and learn about archaeology. 

 
     Interpreting finds in their historical context is an important part of archaeology.  This often requires going to historical records, other field reports, or museum collections.  Sometimes identification is made in unexpected ways.

Is this the what the famous Hunley signal lantern looked like?  
Click the link for photos and speculation.  

Click for images and speculation about the signal lamp.


Later Activity
     After a considerable hiatus a fifth hull plate was removed in July 2003.  A quarter panel was removed from the forward tank for conservation study and to provide access to the tank for sediment excavation.  The plate is part of a panel that was previously though to be a single piece.  The only other access, a small hole on the starboard side and the opening over the cabin bulkhead, is insufficient for this task.   Location of the fifth plate - looking forward
Location of the fifth plate - looking aft      A similar situation exists in the aft tank.  Although there is a large hole on the starboard side of the tank, it is far aft, limiting access to the remaining sediment.  Access over the bulkhead is limited by the steering linkage, the propeller flywheel, and the other mechanisms in that location.
I included a speculative frame stiffener in the above renderings.  A Post and Courier photo shows a stiffening ring an inch or two forward of the aft edge of the opening in the forward ballast tank.  There appears to be one in the same position in the aft tank.
     There is a small possibility that the crew tossed objects into the tanks over the bulkheads or that the builders left a tool or two behind.  The expectation was that only more ballast weights will be found (but see below), but the sediment layers may provide further clues to the loss of the submarine.
Remaining sediment - week 2.
The graphic above shows the approximate areas of remaining fill in dark gray.  The current hull openings are shown cross-hatched.  My guess at the extent of the first two weeks of excavation is shown in lighter gray. In the forward tank excavation may have reached further back toward the cabin than I've shown.  

Week 1
The Hunley team spent the first week of the final excavation phase preparing for removal of an aft ballast tank quarter panel and excavating the area exposed by the earlier removal of a forward quarter panel. In lo-res web cam views a smooth, blue-black surface appeared when the concretion was removed form the aft panel area and began to look rusty by the second day.  I noticed a similar color when I visited the lab prior to excavation and when the first panels were removed.  I still don't know if this is the natural color of the bare iron or a preservative coating. 
     In addition to the expected iron ballast bars, the archaeologists found a small wood cask near the bottom of the forward tank.  Initial speculation about the cask, which is partially filled with different sediment from the tank, offered several possibilities:

  • Float to indicate tank depth
  • Chamber pot
  • Container of some liquid

Just small enough to pass over the top of the bulkhead, the cask might have been dropped in by accident. It's also possible it was left behind during construction. If it were a float, it seems to me it would have been found higher up in the tank and would contain similar sediment to the tank.  It's not likely a cask of hooch would have been placed in the tank, but it might have been wedged at the top of the bulkhead and fallen in.  We could better speculate on the chamber pot possibility if we knew a little more about the cask.  If a chamber pot were used, it's possible it was dumped out in the tank and could have been accidentally dropped.  It seems to me less likely that this would have been a task for the commander, though, unless he had his own. Of course the aft bulkhead is less accessible because of the propulsion and other machinery located there.  If the cask were dropped in the tank, there's no reason to suppose this occurred on the final mission.  Once in there it would be difficult to retrieve.

Week 2
The aft ballast tank quarter-panel was removed Tuesday of the second week.  A fuzzy web cam snapshot showed probably 16 rivet holes along the panel's length and perhaps twelve along one vertical edge.  There appeared to be a structural feature on the forward side of the new opening, probably a stiffening ring, similar to that seen in the forward tank opening.  The aft portion of the area appeared to be have been already excavated through the large opening on the starboard side.  Excavation through the new opening proceeded quickly in neat stages, following standard archaeological practice. In the later stages, the steering rod was clearly visible running through the upper part of the tank.  At the end of the week, the slightly different perspective afforded by filling the preservation tank revealed the propeller shaft as well.

Week 3
There were no announcements this week, so progress can be measured only by the very limited oversight provided by the web cams.  There was activity at both tank openings.  The interior cam showed the forward tank excavation had reached the cabin by Tuesday.  Excavation in the aft tank was certainly proceeding toward the cabin.  

Week 4
Again, no announcements from the Friends.  Activity in the forward tank, as gauged by the web cam view, appears to have completed by midweek.  Conservation hoses and pipes, other extraneous equipment, and water puddled on the cabin floor were removed, probably for detailed photography, including what seemed to be a a flythrough video when a camera was moved along a guy wire run the length of the cabin.  Even the interior web cam was dismounted, providing a momentary and murky view aft showing the opening into the tank.  The rectangular shape where steering linkage passes over the bulkhead was clearly outlined by the light from the tank.  On Friday one of the team was in the tank working forward.  Activity ceased early perhaps indicating excavation is complete.

Later
At the end of week 7 the Friends finally announced the completion of the tank excavation.  They revealed that the cask found in the forward tank the first week probably contained a caulking compound and that a chisel-shaped tool found nearby was probably used with it.  They reported that a coil of rope was found in the aft tank.  They also reported activity in the crew cabin to remove previously unidentified items including some small tools.
     The announcement included some speculation that the cabin tools might indicate repair activity during the last hours of the Hunley.  A report in the Post and Courier included the cask and iron in this complement of tools.  My own belief that artifacts found in the tanks were left there during construction or maintenance that took place in port.  The initial report of  the removal of the forward tank plate indicated the plate showed signs of repair.  The location of the cask far forward in the tank weighs against it's somehow being stored there or dropped there that night.  The coil of rope in the aft tank is also problematic.  I doubt rope would be stored in the tank and the considerable amount of machinery in the cabin near the aft bulkhead makes it improbable that it drifted or was dropped there during the last voyage, although losing it there during maintenance or similar activities is always a possibility.  My own thought is that it was used as sealing material during construction.  
     The
Post and Courier report revealed a pipe between the two ballast tanks.  There was no mention of how this was accomplished or connection with the pumps or valves.  As always a photo would be appreciated but these are rare these days. 

Finally, the next phase of activities was announced.  After additional laser mapping and x-ray documentation of the interior, the internal mechanics will be removed for separate conservation.  The bench, crank, pumps, and ballast ingots were specifically listed in the Post and Courier report. 


Even Later Activity
From the beginning of this project archaeology and conservation have been applied together.  The archaeologists excavated during the day.  Every night the Hunley was kept in a preserving underwater environment.  As features were exposed, the conservators came in to treat and protect them.  After the removal of the sediment, conservation has become the dominant process, but archaeological recording techniques are still applied as concretion is removed since artifacts and features are exposed during the removal.

     In January 2005 the Friends announced the removal of the crew's bench.  At the time of the announcement the two forward sections had already been removed and work was proceeding on the final section.  They revealed the total length as 17.85 feet, clearly converted from the metric used for documentation throughout the project, and described the forward section as six and a half feet long.  My reconstruction had that section correct but my total length was about 20 inches too short.  The report mentions the aft section is "mounted within submarine's aft pump mechanisms" so it is likely I have that one too short.  I had used a ĺ-inch thickness rather than the announced three centimeters, a rather careless mistake on my part.  Standard wood measurements (2x4, 1x12, etc.) have decreased in actual size over the years, but I recall that the studs in my not so very old house in Connecticut measured a full two by thee inches.   The report also described the the bench as still 50% covered in lead-based paint, a fact that has been obvious in the numerous bench photos previously released.
     Removal of the bench will give the conservators better access to the heavy concretion still under the bench especially in the aft part of the cabin.  A number of artifacts remain in the concretion. 

     In mid-February 2005 the scientists showed the removed bench to the press and revealed it is "heavy ... conifer, pine-related wood" and had been painted several times with a white, oil-based paint.  This supports my reconstruction concept of a white interior.  The scientists stated that the condition of the bench indicated it had been in an oxygen-free environment and suggested that the cabin did not fill with water early on.  Associated Press photos showed what appeared to be each end of the center section.  The aft end showed a long piece split off the back of the bench that had been apparent in earlier published material.  The forward end revealed three metal fasteners - probably nuts - embedded in the wood a half-inch or less from the end.  The Post and Courier revealed the presence of a joining block here.  Additional low resolution photos published later in the Friends' Blue Light newsletter don't provide much additional information, but show that concretion was removed from the stiffener rings where they pass through notches in the bench.  Earlier photos show this concretion spreading out some over the wood.  I considered and ultimately rejected this as evidence of bracket locations.  The latest photos confirm my identification of the center section above, but offer no new clues about the mounting mechanics.
 

     By mid-April 2005 the depth gauge had been removed.  The Friends reported that the glass tube must have broken during the last mission or shortly thereafter since a pool of mercury was found on the cabin floor beneath the sediment.  Although the dangers of mercury were not as widely understood then as they are today, it's unlikely that the puddle would have been left there if the break had occurred earlier.  The apparatus was reported to be three feet high and mounted on the port side of the cabin at Dixon's position.  We've known since the Smithsonian presentation that the gauge inlet is on the port side just above the ballast tank valve inlet but mounting the gauge along the side seemed strange to me.  The hull side is curved and the apparatus would need to be curved or bent to be out of the way, especially since the dive plane control lever moves through that area.  At the time I speculated that the report included a misunderstanding and that only the inlet was on the port side.  Dixon's shelf has a cutout in its forward edge next to the tank bulkhead and photos show some vertical lines in the bulkhead above and below the shelf.  Subsequent publication of an x-ray of the gauge and close examination of earlier photos verified my speculation that this was a better position for the gauge.  (Read more about this on my reconstruction page.)  The shelf must have been removed first to permit removal of the gauge.
    The speculative graphic at right shows the gauge approximately as it looked upon removal.  The concretion is probably more extensive than I've shown and the inlet tube may extend further to the left.

Depth gauge as removed

     The gauge announcement was made while I was pondering the possible effects of the torpedo detonation, probably a pressure surge on the order of 950 psi, on the Hunley leading to a Eureka! moment.  It appears from what we have heard to date that the hull suffered little damage from the explosion, but the thin glass tubing, less than ľ" diameter, subjected to the same pressure as outside the hull may have burst.


     The first deadlight was exposed in June in the center panel, the first removed back in 2001.   The news reports used the term to refer to the iron covers over the glass, whereas earlier reports had referred to glass ports themselves.  The nautical term can apply to either.  An interesting thing to me was the great difference between the amorphous blob of concretion that concealed the very cleanly defined shape of the cover hardware below.  I had noticed this before where some of the rivets around the forward hatch had been cleaned, but the published side-by-side photo of two deadlights, one cleaned, one concreted, brought the message home.  Many secrets of the Hunley construction will be revealed as more concretion is removed. 
     Several views of the sub have provided clues of what we can expect as the process continues.  The joint between the hatch covers and coamings is now wrapped, hinting that there has been activity here.  I'm afraid, as Robert Neyland stated several years ago, that the Hunley will need to be dismantled to separate the different kinds of iron of its components.  

     A week later, the Friends announced the discovery of an oddly marked copper plate on the floor of Dixon's station.  Traces of zinc on the plate, a piece of copper wire found nearby, and what was described as a spool of wire hanging in the forward ballast tank led to speculation that this might be part of an electrical detonation system for the torpedo.  The spool is actually a loose coil that was hanging in the tank on the inlet pipe.  A photo taken in 2003 during the forward tank excavation but just published shows a coil of approximately one-foot loops.
     Clemson University experts are studying the plate.  I'll wait for the their report but I'm initially skeptical of the interpretation.  I think that battery technology of the time required a container with a liquid electrolyte.  Unless the remains of such a container are found, I think it's more likely that Brian Hicks' suggestion that wire was used for the mechanical trigger lanyard is correct.  (See my reconstruction page for a different speculative thought about the plate.)
     The initial assessment by the Clemson scientists, published in the fall issue of Blue Light (Volume 17, October 2005), validated my battery technology comment above.  The same issue includes a sidebar expanding on Brain Hicks' lanyard speculation. 

     To end 2005 the Friends announced removal of the glass from the forward tower viewports.  No official photo was released, but Brian Hicks' Post and Courier article included several.  The clearly pictured port-side viewport closely matches details in an x-ray displayed in the Warren Lasch Conservation center.  Externally, the viewport has an outside diameter of nearly four inches with an opening of about 2 and one-third inches.  The port is affixed to the tower with four rivets or bolts.

     In May 2006 The Blue Light reported the discovery of rubber disks blacking out ports in the forward hatch tower.  The plugs had string lanyards for easy removal or to keep them from being misplaced when not in the ports.  Some of these were found in place, but at least one was discovered on the floor of the submarine.  The report is incomplete providing a count only for the forward hatch, but these must have been standard for both the forward and aft hatches.  To date no photos have been published of the porthole work on the aft hatch.
      The article also mentions "concreted rods" on the floor of Dixon's station that may be "remnants" of the forward hatch latching mechanism. 

     In Jul 2006 the Friends announced the discovery of parts of the forward hatch latch mechanism apparently stored on the floor on the left side of Dixon's station (as reported by Brian Hicks in the Post and Courier).  The mechanism appears similar to the latched aft hatch mechanism, a flat, rectangular bar with a hole threaded on a rod attached to the hatch lid.  The various reports are not consistent, but we can infer from these and earlier reporting (see above) that two major parts of the forward latch were found behind the rudder linkage and ballast tank interconnect pipe.  As always in archaeology, where artifacts are found is as important as the artifacts themselves.  Since the Hunley lay on the bottom listed about 45 degrees to starboard and the linkage and pipe run on the port side, it is unlikely that the latch could have fallen to that position, for example, as a result of the later event that made a hole in the hatch coaming.  The dive plane lever with its large counterweight is above the position, making it unlikely the mechanism fell there even if the sub was upright.  The most likely implication is that Dixon stowed the latch there.
     At about the same time, the monthly member update announced the discovery of another port in the aft hatch tower.  Unfortunately, no location or new total number was mentioned.  Assuming there were earlier thought to be three - one on each side and one in the hatch cover - the new one may face aft, providing a view toward the original towed torpedo.  A port facing forward is less likely because hinge mounts.

     Conservators removed the rear hatch cover in mid-September 2006.  Removal was necessary because the cover deadlight glass could not be removed from outside and the latch mechanism prevented access from inside the sub.  Upon removal the conservators found what may be a small valve in the lid about halfway between the forward edge and the deadlight.  Removal of the hatch cover exposed the top of the hatch tower, revealing the actual thickness of the original metal.  Very nice photos published in the Charleston Post and Courier show the actual thickness to be a very thin 1 to 2 centimeters.  The interior concretion is twice as thick, helping to explain the lack of visible detail.  The concreted latch mechanism is visible in two photos.  A narrow vertical rod with a knob-like tip rises near-center in the hatch tower from a larger crossbar fastened side-to-side below the tower.  The smaller hatch-top photo reveals a similar knob near the center of the lid.  What may be the end of the suspected valve handle is just discernable.

     Over the years there has been much speculation about what caused the large hole in the Hunleyís aft ballast tank.  In mid-November 2006 Brian Hicks reported in the Post and Courier that this and other damage could have been caused by strong water currents sandblasting the iron.  The starboard hinge on the aft hatch cover is noticeably worn as are many of the view port mounting rings.  The scientists believe itís possible that even the now-familiar curve of the Hunleyís bow is a result of this sand-laden current scouring.  The damage is mostly on the starboard side, probably because of the extreme list to this side.  A swift current moving through here could have been accelerated by the Venturi effect and whipped up additional sand.
    
Current scouring is natural around wrecks, which change the flow over the sea bottom.  Typically a bowl is formed in the sand under the wreck and it slowly sinks until it is buried, at which point the original equilibrium is restored.  According to the Hunley and
Housatonic site assessments, both of which provide considerable analysis of the effect of currents in the area, the submarine was completely covered in about 25 years.   
    
Divers working on the Hunley site attest to the strong normal currents in the area and it isnít a big leap to imagine the effect of a sand-laden, Venturi-accelerated current on the iron.  The current would not have been uniform, but could vary considerably within just a few inches.  Places subject to high current would experience more sand erosion than other areas.  The hatch hinge, projecting out into the current, could experience very heavy erosion, as could places near the sea bottom.   In time the hull plates subject to the highest sand scouring could have been worn so thin that minimal corrosion could perforate them.  Areas subject to very high scouring could have been perforated by the current alone.
 
     A photo of the hatch lid published in Blue Light number 22 (Winter 2006) shows considerable damage to the starboard side of the hatch lid rim.  Unlike the smooth distortion of the hinge, the damaged surfaces on the rim are jagged, looking more like a fracture than wear.  This could be a consequence of erosion and deterioration or could be the result of some kind of impact.

     In January 2007 conservators opened (rather than removed) the forward hatch.  The intent was to expose the rubber seal in the lid so it could be removed.  This must be done before the chemical corrosion treatment of the metal can begin.  However, some of the concretion around the hole in the forward hatch tower is attached to the lid and covers the seal.  It is possible that the damage occurred any time from the night of the submarine's loss to many years later.  The hole could be the result of a violent impact or the result of continuous wear in the sand-laden current.  All the concretion around the hole needs to be carefully analyzed to place this damage in the Hunley timeline.  Removal of the seal will be delayed until this study is complete.
     In April 2007 the Friends finally published a photograph showing the forward-looking ports.  These are located nearly at the top of the hatch tower, not low down like the side ports. 

     At the end of August 2007, the Friends of the Hunley announced the discovery of several small pieces of cast iron on the cabin floor beneath the forward hatch tower.  One of these pieces is curved and, as demonstrated on the History Channel program Digging for the Truth in September, is close to the curvature of the port glass of the starboard-side view port.  This raises the possibility that it is part of the missing port-side view port.
     Soon after this, during the member appreciation events, the Friends publicized earlier speculation that the distinctive curve of the bow is a result of sand scouring and that the original shape was straight up and down.  I've updated my plans for this, although all the other images still show the curved shape.

     In January 2008 conservators removed the aft pump from the Hunley.  This is part of the continuing process of separating materials that would be damaged by the chemical treatment that will stabilize and preserve the iron hull.  To gain access to the bolts that attached the pump to the hull, in December they had removed the approximately 500-pound aft-most keel weight.  This is one of four that were permanently attached as opposed to three that were designed to be dropped with releases in the cabin.  Brian Hicks revealed that the top of the weight was curved fit snuggly to the hull but "there was a little wood between the block and the sub".
     Photos of the pump reveal a confusingly complicated mechanism, weighing on the order of 150 pounds, with similarities to the forward pump.  There is what appears to be a large valve attached, with a pipe extending forward a foot or more before making a right angle turn into the cabin side.  The position of what appears to be the valve handle leads me to believe it is in the open position.  This likely outlet line was fastened to the hull by a square plate.  Other parts attached to the removed mechanism may be other valve assemblies.  The Friends plan to use x-rays to determine valve positions.  Earlier photos of the aft section showed what was apparently the pump handle.  This feature does not appear in more recent photos and it was not attached to the pump at its removal.  (See the tanks pop-up on the reconstruction page for some speculation on the pump valve system based on earlier reports.) 

     Conservators removed the forward pump from the Hunley in late May 2008.  As with the aft pump it was first necessary to remove the fore-most ballast block to gain access to the four lower attachment bolts.  A photo released by the Friends of the Hunley shows how closely the block is fit to the hull.  There is a rectangular groove running half way down the top of the block to accommodate the joining strip on the bottom of the tapered portion of the hull. 
     This pump was attached to a hull stiffener ring by a bracket at the top.  The pump handle is still attached to the pump.  The pivot end of the handle had to be unbolted from another bracket on the stiffener to permit removal.  As with the aft pump, the outlet pipe ran forward to a right angle bend and attached to the hull by four additional bolts or rivets.  There appears to be a valve in this pipe at the pump end, with its control handle on the bottom.  Itís likely that this pipe supported Lt. Dixonís seat, so placing the handle on the bottom kept it out of the way, but accessible.  To me the valve appears to be closed.  What may be the open end of the inlet pipe is visible at the bottom attachment plate in a photo published in the Charleston Post and Courier.  A curious Y- or C-shaped mechanical feature straddles the lower portion of the pump in the same photo.  The top part of this feature is visible in much earlier photos of the pump area.

     In early 2015 the Friends released photos and videos showing the Hunley's exterior completely cleaned of concretion, revealing new details of its construction.  The first thing I noticed is that seams on the lower hull in the tapered sections of the hull don't match up with those on the upper hull, evidence of the use of existing metal plating in the Hunley's construction.  The photos I've seen don't show the central hull in sufficient detail, but I suspect the seams there match.  Some interior photos showing the rivet plates support this.
     It appears that the conservators removed anything under the concretion that was not physically attached to the hull.  I've not seen anything describing what caused many of the bumps.  In the past, we've tried to interpret these as equipment but they could be natural or otherwise extraneous.  Pending further information anything no longer on the hull must be considered unknown.
     The new photos do confirm some details in Chapman's painting, but one prominent feature he shows on the port side just aft of the aft hatch tower appears in the photos to be two much less noticeable bolts.  My initial guess, pending  further investigation is that these were associated with the aft pump installation. 
     I've updated my plan drawings, available on my reconstruction page,  to reflect what new information I've been able to extract from the photos.

     The Fall 2016 Blue Light (Vol. 48) includes information about the depth gauge as well as post-conservation photos.  The four-page article reports a wood plug "jammed into" the glass coupling.  This could only be done if the glass tube, indicated to be some 30 inches long, was removed.  The article speculates plug was intended to disable the gauge, but this seems unlikely to me because the remains of the glass tube as well as some mercury was found on the floor of Dixon's station.  To me it's more likely that the glass broke or came loose and Dixon used a piece of wood to staunch the flow of mercury, perhaps fearing water could follow.  As the glass remained in the cabin, we might speculate this happened during the final mission, but it's not certain that the cabin would have be tidied between missions, removing the likely broken glass.


 

I will update this page when significant additional information is released.  

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17 Sep 16