Wednesday, 2 April 2014

IRON WORK

Oliver Lang's 1845 stern redesign. Note the iron strapping. 

Oliver Lang’s 1845 modifications to Terror’s stern involved a significant amount of iron reinforcement. In my last post, I documented the design of the iron staple knee, which was central to the construction of the propeller well and new rudderpost. However, Lang also added four large iron straps to reinforce the joints between the keel, the rudderpost and the sternpost. These straps were u-shaped and passed between the false keel and the keel, permitting the former to break free in the case of the stern running aground.
According to Lang’s notes, the straps appear to have been bolted entirely through the width of the stern to provide extra rigidity. This created an exceptionally strong iron-laced structure, a design which exposed Lang's worry about the ice pressure to be exerted on the Terror’s stern.

The 1845 stern modification plan reveals that the straps were 4 and 1/2 inches wide, with bolts approximately 1 and 1/8th inches in diameter. I estimate, based on bracing and strapping shown on cross section plans of HMS Erebus/Terror and HMS Investigator, that they were ca. 1 to 1.5 inches thick.


All of the parts shown below are made from larger brass strips, which were cut, filed, and drilled by hand. The bolts are made from brass straight pins; the heads were filed by hand to scale (2 inches) and soldered into place. The brass was then blackened to simulate iron. 


The foremost strap prior to adding the bolts. 

The staple knee and remaining straps with bolts soldered in place. The three aft straps would normally look similar to the one on the right, but I've decided only to model the visible portions of the straps (i.e. the portions not buried between the keel and false keel). Each is composed of two parts to be glued on opposite sides of the model. 


Detail of the newly added bolts. 





Brass parts soaking in the blackening agent. 


The finished parts.


The iron reinforcements in place (dry fit only until the propeller rails are completed).


Again, just a test to see how they will look when finally installed. 









2 comments:

  1. Thanks for keeping us up to date. Very helpful.

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  2. Thank you William. More to come soon on the propeller and its rails.

    ReplyDelete