BUILDING HMS TERROR GIVEAWAY!

 Like HMS Terror? Like coffee or tea? This mug could be yours!

Today is the 202nd anniversary of Terror’s launch in Topsham, Devon, in 1813.

To celebrate, I’m giving away five coffee mugs printed with an accurate plan of Terror’s outboard profile, as she was fitted in 1845. I designed the plan and the mugs specifically for Terror’s birthday, and the giveaway is my way of thanking my readers for their comments, insight, and support.

Please note that I will not be selling the mugs; you will only be able to get one through the giveaway.

To enter, all you have to do is “share” one of my blog posts on public social media (Facebook, Twitter, Instagram, Pinterest, your personal blog, etc.), and provide proof to me that you’ve done so. And I’ve made it easy to share – simply click on your favorite post, and then go to the “Share it” section on the right side of the page. The five individuals with the most shares will each win a mug.

The plan used on the mug is similar to that shown in
last year’s Canadian Geographic Magazine.

The HMS Terror mug is Mini-Crozier approved!

Giveaway Details:

The giveaway item is one mug printed with an outboard profile plan of HMS Terror, as she was fitted in 1845. Only five mugs are available.

To enter, please “share” one of my blog posts on public social media (Facebook, Twitter, Instagram, Pinterest, blogs, forums, etc.). Paste evidence that you’ve shared (a link or screen capture) into an email and send it to me directly. Each time you share a post, you’ll receive one entry to the giveaway

“Shares” must be posted to public social media accounts (no private groups or websites, please).

The giveaway will run from June 29th, 2015 to July 13th, 2015. The five individuals who have the most “shares’ during this period will each receive a mug. In the case of a tie, winners will be selected randomly. Those receiving a mug will be notified on July 14th, 2015.

Mugs will be shipped on the week of July 20th by regular parcel post, to any address provided by the winner(s). Unfortunately, I cannot guarantee safe delivery of the mug; however, they will be thoroughly packaged, in a custom protective sleeve and box.

Best of luck, and I look forward to sending you a mug! If you are looking for content to share, why not try my most recent post?

Happy birthday to HMS Terror, and sincere thanks to everyone interested in her!

PULLING A RABBET FROM TERROR’S HAT

Last month, I finished the most angst-ridden part of my project to date - cutting two seemingly miniscule 1.5 mm wide grooves along the length of the keel and stem of my model. These v-shaped notches, known as rabbets, provide a seat for the edges of the hull planking where they meet the centreline timbers of the ship. On a plank and bulkhead model, it represents a critical reference point around which the hull architecture is based.  

My trepidation was rooted in the fact that the rabbet position isn’t shown in Terror’s 1836 draughts [1] (the 1839 draughts [2] only show the rabbet position for Erebus). Normally this wouldn’t be an issue, as Terror’s 1812 [3] profile plan clearly shows the position of the rabbet. However, the 1836 plans show that Terror’s bow, and in particular her upper deck and bulwarks, were extended forward approximately 12.5 inches (why this was necessary is still a mystery to me). This implied that her rabbet position must have been moved forward as well, to accommodate a smooth run of planking along the bow.

The rabbet carved into the model’s keel. Like the merchant ships which were the basis for Terror’s 
design, the 1812 draught shows the rabbet was taken out of the centre of the keel 
(incidentally, this position probably contributed to her poor sailing qualities).

I had originally assumed that Terror’s cant frames, hawse pieces, and bollard timbers may have been modified to accommodate this lengthening of the deck. This wasn’t an unwarranted assumption, because Terror’s 1836 profile plan shows that Terror’s upper stem piece was extensively remodeled, suggesting a significant refit of the bow timbers.

However, after further consideration, I’ve come to the conclusion that such extensive modifications were very unlikely. We know that Terror’s original top-timbers and bulwarks were entirely levelled when she was caught in a hurricane near Lisbon in 1828 [4]. This means that replacement bulwark stanchions needed to be installed when the ship was repaired. The upper deck may have been expanded at this time, but I suspect this occurred in the 1836 refit as the solid chock channels provided an opportunity (and platform) to most effectively hide this shift forward. In either case, because her bulwarks had been levelled, the modifications could have been made without extensive reworking of the bow timbers.

Therefore, my solution is to leave the rabbet position precisely as shown in Terror’s original 1812 draughts and to rely on modified bulwark stanchions to account for the lengthened deck. This permits me to move forward with the project with the least amount of conjecture, because the only speculation I need to make is about the construction of the most forward bulwark stanchions.

The port stem rabbet .

Another view of the rabbet - note how it "opens" slightly closer to the heel of
the stempost. 

A dummy section of planking dry-fitted into the rabbet, showing how it interacts
 with one of the station bulkheads. 

Settling on a final position of the rabbet allows me to finally assemble the bulkheads and begin planking the model. This decision also permitted me to finally draft a plan of Terror’s complete bow architecture.

Profile of the Terror’s bow architecture, showing the manner the bow was
strengthened for polar exploration service. To accommodate the
lengthening of the deck, I added a conjectural 12 inch chock fayed to
the fore edge of the bollard timbers and cant frames, against which
the bulwark stanchions would have been bolted.

Plan of Terror’s lower deck, detailing the layers of planking and
metal sheathing added to the ship

The plans expose the effort the Admiralty placed on strengthening the ship’s bow at the waterline. More than 55 inches (4.5 feet) of iron reinforced oak separated the stores on Terror’s orlop deck from the water. Near the foremast step, that distance multiplied to nearly 12 linear feet. James Clark Ross [5] tested these reinforcements in a most daring fashion during his Antarctic Expedition. By January 5th, 1841, Ross had spotted what he thought was open water south of the Ross Sea but found his way to it blocked by a ring of thick pack ice. Confident in his ships, he sailed along the barrier until he saw a “favourable point” and, under sail, rammed the Erebus and Terror into it for an hour, eventually fracturing the ice and punching his way through. He discovered the Ross Ice Shelf six days later.   

Footnotes:

[1] National Maritime Museum Object ID: ZAZ5672, ZAZ5663

[2] National Maritime Museum Object ID: ZAZ5673

[3] National Maritime Museum Object ID: ZAZ5615

[4] 1835. Narrative of the Wreck of H.M.S. Terror. United Service Journal and Naval and Military Magazine 1. Pages 229-236.

[5] Ross, Sir James Clark. 1847a. A Voyage of Discovery and Research in the Southern and Antarctic Regions, During the Years 1839-1843: Volume I. John Murray, London. Page 176.

LASER CUTTING TERROR’S BULKHEADS

I have arrived at the stage of my build where I am assembling the bulkheads that will give shape to the ship’s hull. I have already created bulkheads for this model using the traditional method – gluing the plans to plywood and cutting them out using a scroll saw. 

The old bulkheads - cut using a scroll saw (prior to sanding). 

However, I recently decided to change the way I will construct the bow of the model. I had originally modified the forward stations to account for the extra bolsters and planking at the bow, but I've recently decided to try to build these fittings (as a means to determine how Rice actually reinforced Terror against the ice). This necessitated rebuilding the two most forward station bulkheads. 

And this gave me an excuse for a whole new mini-project.

Following a current trend, my local public library recently opened a prototyping studio, which includes design software, 3D printers, and an Epilogue Mini 24 Laser Cutter. The library allows you to book the equipment for several hours each month - for free. I've wanted to experiment with a laser cutter for some time, and since I needed to make new bulkheads anyway, I decided to recut all of them. My hope was that it would result in a more accurate build.

The Epilogue Mini 24 Laser Cutter. The bed capacity is 12" x 24". 

The cutter works very much like a traditional printer and will engrave (raster) or cut (vector) based on the thickness of the lines shown in the image file (I used high resolution PDFs for this). My first attempt, using factory recommended settings, was somewhat of a disaster, resulting in charred and smoldering wood and unusable pieces (plywood is notoriously difficult to cut because of its inconsistent composition).

My first disastrous attempt. Note the burned and charred edges.

For my second attempt, I conducted some tests and determined the proper power settings needed to cut 5mm plywood with the thinnest, most accurate, cuts and a minimum of charring and burning [1].

As a test, I cut a series of discs with different power settings. 

The appearance of the cut edge with the proper settings (no charring). 

I engraved the station markings on each bulkhead.  The machine automatically engraves before cutting.

The bulkheads being cut. 

You can tell the cut was successful if the part drops away from the sheet. 

A finished sheet. 

Each bulkhead fits into slots on the false keel. 

The bulkheads slide snugly into place. 

Test assembly proceeds. This is just a dry -fit. 

The bulkheads dry-fitted in place. They need to be properly aligned, but I'm happy with the run already.
Mini-Crozier allows us to visualize how large Terror actually was (quite small for a Royal Navy vessel).  

A view from the bow.

This view shows the run of the ice channels very nicely. 

A top-side view from the stern. The bulkheads are just dry-fitted here and will need to be
aligned properly before gluing. 

I am very pleased with my experience using the laser cutter. The bulkheads are much more accurate than I could have produced by hand, and the process took about a tenth of the time normally required to cut and sand these parts. I will certainly be using it again when I need to cut more complex shapes and components for my build. 

Footnotes:

[1] For those interested, low speed, power, and PPI settings are a must, and the recommended wood settings for the Epilogue Laser will not work on plywood. Your goal should be a setting that will just barely cut completely through the wood, as this results in the thinnest cuts and edges that are browned, but not charred. My settings for good quality 5mm birch plywood were: Speed = 10, Power = 38, and PPI(Frequency) = 150.

HELPING TO BUILD A DIFFERENT KIND OF MODEL

Erebus drifts south in the ice, a still from Franklin's Lost Ships.
© Lion Television and 90^th Parallel Productions.
Image provided by Andrew Gregg, used with permission.

Last week, Lion Television, in collaboration with 90^th Parallel Productions, aired a wonderful new documentary, Franklin’s Lost Ships, on CBC’s The Nature of Things. The show was directed by Ben Finney and produced by Andrew Gregg for CBC, PBS, and Channel 4.

The documentary chronicles the 2014 Victoria Strait Expedition, culminating in the discovery of HMS Erebus by Parks Canada archaeologists and their collaborators. The film uses detailed computer graphics, historical reenactments, and interviews to bring the Franklin mystery into sharp focus - in ways we have never seen before.  

One of the most unique aspects of the documentary is the use of computer animations to bring Franklin’s ships, HMS Erebus and Terror, to life. I was fortunate to be asked to consult on the team’s attempt to recreate the ships and I have been corresponding with the producers since December of last year. I know that I wasn't the only researcher they consulted on the ships, so it was definitely a crowdsourced project.

Erebus and Terror push their way through the ice - a still from Franklin's Lost Ships.
© Lion Television and 90^th Parallel Productions.
Image provided by Andrew Gregg, used with permission.

Andrew Gregg, a producer for 90^th Parallel, oversaw the model construction process, which was undertaken by Redlab Digital, a Toronto-based visual effects studio. Mike Brown of Lion Television was also heavily involved, and Karen Kershaw led the artists at Redlab. The team’s goal, as stated to me, was to produce the most historically accurate reconstruction of the ships possible. My admittedly small role was to provide feedback and comments on the various drafts of the model build.

I sent Redlab copies of my plans and they consulted historical data such as paintings, drawings, contemporary ship models, and the original draughts of the ships. As they constructed the model, the artists would provide rendered images of different angles of the vessel to Andrew and Mike, who would then pass them on to me for comment. The process involved many drafts and I marked-up many images as, polygon by polygon, the ships began to take on a recognizable shape.

Until late February the ships were untextured grey geometric models, but I remember smiling broadly when Andrew emailed the first textured (fully coloured and detailed) render. Here was a complete view of one of Franklin’s ships, with the correct colour scheme and all of her unique systems, and I was thrilled to see it.

Fully textured render created by Redlab, showing a view of the hull of the ship. Note the iron bow plating.
© Lion Television and 90^th Parallel Productions.
Image provided by Andrew Gregg, used with permission.

Fully textured render created by Redlab, showing a view of the upper deck. Note the diagonal deck planking.
© Lion Television and 90^th Parallel Productions.
Image provided by Andrew Gregg, used with permission.

Fully textured render created by Redlab, showing the ship
covered in ice and snow.
© Lion Television and 90^th Parallel Productions.
Image provided by Andrew Gregg, used with permission.

Of course, readers of my blog know that I could never be fully satisfied with the accuracy of any model, and I worried that I would annoy Andrew and RedLab with all of my suggestions for changes. However, I learned quickly that they wanted to include every detail they possibly could, and they made changes to the models right up the last minute possible before their airdate.

Erebus and Terror sail again, a still from Franklin's Lost Ships.
© Lion Television and 90^th Parallel Productions.
Image provided by Andrew Gregg, used with permission.

Are there errors in the models? Sure there are. But these are relatively minor given the project and they are primarily because of time constraints. There are issues with the ice channels, the masts and rigging, and the various esoteric fittings bolted to the ship. But I suspect there are only a handful of people on the planet who could point out all of the specific issues (and most of them are currently diving on the Erebus).

I’m convinced that these are the most accurate models of Franklin’s ships ever committed to film, and I want to thank Andrew and Mike for involving me in their great project. I’ve spent the better part of two years trying to build a wooden model of HMS Terror, but I never thought I’d have the opportunity to see her sail in arctic waters again. Watching Erebus and Terror plough their way through the ice allows us to better comprehend the astonishing journey of these remarkable exploration vessels.

If you read my blog, don't miss this wonderful documentary.

Erebus takes advantage of her screw propeller. A still from Franklin's Lost Ships.
© Lion Television and 90^th Parallel Productions.
Image provided by Andrew Gregg, used with permission.

Acknowledgments: I would like to thank Andrew Gregg and Mike Brown for allowing me to post renders of the ships and stills from the documentary. It was a pleasure to work with them.

ASSEMBLING TERROR’S STERN

I haven't posted an update regarding my model in several months. While I've kept busy with side projects, the real reason for my delay is that I had reached an impasse with Terror’s stern.

As I've discussed in previous posts, the sterns of Franklin’s ships were modified in 1845 to accommodate a new auxiliary screw propulsion system – to be used as a time saving device “providing the wind should prove contrary or a dead calm” [1]. There are two sources of data on these modifications: Oliver Lang’s original design plan [1], and its counterpart, a contemporary model of the design [2]. I had purchased full resolution copies of the plan many months ago, but unfortunately Lang did not include a cross section in his draught. That information could only be gleaned from the contemporary model held at the National Maritime Museum’s storage facility in Chatham.   

The contemporary model of Oliver Lang's 1845 design. 

National Maritime Museum, Greenwich, London (SLR2253 [L2251-001]).

Used under Creative Commons Attribution-Non-Commercial-ShareAlike (CC BY-NC-SA) license

Fortunately, I recently had an opportunity to visit the Chatham model ship facility. Assisted by the expert curators, I was able to study the stern model in detail. It is quite unique, being constructed using a series of carved blocks arranged to conform to the position of major structural and engineering elements of Lang’s design.  The information I gathered has allowed me to complete my construction of the stern;  below, I’ll reveal the new information I've learned from the contemporary model, while documenting my final assembly of Terror’s stern:

1) The propeller well used to raise and lower the screw was rectangular, almost square-sided, with the sternpost and rudderpost forming the fore and aft sides of the well, respectively. To accomplish this, thick timbers were bolted to the sides of the rudderpost and sternpost [3]. The rudderpost bolsters were much more complex than I originally assumed and were each constructed of at least two pieces, with the lower portions tapering gently to the width of the rudderpost, following the lines of the body plan (see here for my original conceptualization of the design).

The stern pieces prior to assembly. The bolster on the left is the old design I intended to use, which was incorrect. 

The overkill method I used to glue the bolsters to the stern and rudderposts. Thankfully this was just a dry-run
(note the older bolster design). 

The  new bolster timbers glued on the rudderpost. Note the groove for the "Lihou" rudder on the
rudderpost. I may need to sand the bolsters somewhat to match the run of the planking as they
may be slightly oversized - but no by much. 

Another angle showing the bolster timbers on the sternpost. The NMM model shows that the bolsters on the
rudderpost are longer than those on the sternpost. 

2) The rudderpost and sternpost were each tenoned into the keel extension, as was typical, but each was secured with a single bolt, which was not indicated on Lang’s plan.  

Marking the precise position of the tenon bolts. 

The bolts were simulated with 20 gauge copper wire, precisely the same as that used on the keel scarphs. 

3) The propeller well was framed on the port and starboard sides in three distinct sections. The upper section included stout rectangular framing fayed to the deck beams, which formed a ledge for a scuttle on the upper deck. Below this, the well was probably enclosed by watertight planking down to the height of the stern timbers. Because of the construction of the contemporary NMM model, such planking was not shown, but it is unlikely that solid timber pieces would have been used, as these aren’t shown in contemporary models.

The heavy framing used to form the top of the propeller well. The upper part of these timbers formed a lip
for a scuttle to the well. 

Planking on the upper section of the well. I've estimated a width of 12 inches. The actual width is unknown.
Note that this section of the model will be covered so I haven't simulated bolts or spikes here. 

A view of the topside of the well. The upper pieces of the sternpost and rudderpost bolsters will be
trimmed at a later stage of the build , but are useful for alignment at this stage. 

4) A new section, clearly visible in the well of the model, started at the position of the stern timbers. This suggests the stern timbers were bolted to the sides of the rudderpost and sternposts to provide major structural support to the new rudderpost and well. This makes good sense, and Lang’s 1845 stern plan clearly shows the stern timbers as a major element of the design. In fact, these new timbers are substantially more robust than Terror’s original stern timbers, suggesting they were an integral part of the strength of the new structure. Again, this type of structure is supported by contemporary models.

The bottom portion of the framing planks were trimmed to match the run of the stern timbers. Note
the rabbet on the rudderpost on the right. 

5) The lower section of the propeller well was composed of the second layer of hull planking where it ran aft, horizontally.  Eventually, the run of the higher planks would have veered away from the straight-sided wall of the well. At this point, straight horizontal planking would have been used to frame the sides of the well. The position where this occurs is marked by a block seam on the contemporary NMM model.

Unfortunately, Lang’s contemporary  model does not include any of the ironwork used to strengthen the stern, nor does it include the propeller rail/track mechanism. I've based these portions of the model on Lang’s plans and extensive research on other contemporary models and designs. This research is outlined in several blog posts (and here, here, and here).

Oliver Lag's stern design. Note the extensive ironwork and the propeller systems.

National Maritime Museum, Greenwich, London (ZAZ5683 [J1529]).

Used under Creative Commons Attribution-Non-Commercial-ShareAlike (CC BY-NC-SA) license.

The iron staple knee glued in place. The knee provided essential support for the rudderpost. 

Mini-Crozier inspects the staple knee in dry dock. 

Lang used iron strapping to further reinforce the stern structure. Here they are made from chemically blackened copper. 

Each strap was glued in place and then the bolt holes were drilled out by hand. 

Bolts glued in place. These were simulated using blackened brass. 

Another view of the completed iron work.

Mini-Crozier frets over the modifications. 

The staple knee was protected by a fitted  chock bolted to the keel section. I carved this using a simple
chisel blade. 

The finished chock compared to the plans. 

Image showing how the chock fits over the knee. Unfortunately it had to be glued in place to permit 
the propeller rails/tracks to be installed. At least I know the knee is there. 

The chock glued in place.

The propeller was raised and lowered using rails or "tracks". These have been modified slightly
from my original versions based on new data. Copper bolts were simulated using wire. 

The rails glued in final position. Note  the  rabbet on the rudderpost 
for the second layer of hull planking. The rabbet will be modified  to 
accommodate the precise run of planking when it is installed. 

 View of the rails installed on the sternpost. 

View of the rails installed on the rudderpost. 

Another view. 

Wooden bolt plugs added to the chock. The bolts were "counterbored and plugged".

The staple knee was bolted to the rudderpost; these bolts were also counterbored and plugged.
I'm not entirely happy with the contrast here and may redo them at a later date.

The completed stern assembly.

Lowering the screw propeller in place (it raise and lowers - and the propeller spins). 

The propeller in position. Unfortunately the angle of the photo makes it look slightly crooked,
but it is not - is spins freely, with very small tolerances as shown on Lang's original plans. 

A view from the stern.

Another angle showing how the propeller was seated.  

Looking down the well from the position of the upper deck .

Mini-Crozier contemplates how the stern will fare in the ice. 

How successful was Lang’s stern at protecting the ship from the pack ice? Parks Canada divers are assessing that currently, and with luck they’ll find the answers soon. We know from historical sources that the Admiralty was concerned about the strength of the design, and that while Lang believed the “sternposts” (sternposts and rudderposts) were as strong as those on other ships, he would not certify that the strength of the filling chocks was sufficient to protect the Erebus and Terror [4].

No matter how vulnerable it made the ship, we can suspect that Lang’s radical redesign also altered the sailing qualities of Terror. Contemporary sailing reports indicate that Vesuvius class bomb vessels were rather lumbering and could not carry sail well, and Ross reported that Terror was constantly falling behind Erebus during his Antarctic voyage, delaying and endangering the expedition.

Recently, Regina Koellner, assisted by William Battersby, transcribed a letter [5] from Francis Crozier to his friend John Henderson, written shortly after the ships arrived at Whalefish Islands in Greenland. In the letter, Crozier provides a brief report of Terror’s sailing qualities: "Our steering is decidedly improved by the alterations on the counter we now sail much more evenly with Erebus which is advantageous to us in many ways." I suspect that the effective lengthening of the keel to accommodate the propeller allowed Terror to sail closer to the wind, finally permitting her to keep up with the more nimble Erebus. It seems the final conversion of Terror to screw propulsion made her a more capable vessel under sail, an irony certainly not lost on Crozier.

Acknowledgments:
I sincerely  thank Regina Koellner for permitting me to post the transcription from her recent research, and William Battersby for alerting me to this exciting primary report on Terror’s sailing qualities.


Footnotes:

[1] Object ID: ZAZ5683

[2] Object ID: SLR2253

[3] Filling frames, similar to fashion pieces, appear to have been fayed to these bolster timbers on the sternpost to accommodate the smooth run of planking over the upper part of the well. My belief is that space between these frames and behind the transom pieces was filled in with chocks, similar to the bow, to add more strength to the stern.

[4] Admiralty Digest, cited from Battersby, William, and Carney, Peter, 2011, Equipping HM Ships Erebus and Terror, 1845. International Journal for the History of Engineering & Technology 81(2):192-211.

[5] AGC/C/5/; MS62/007