Monday 6 January 2014

BOXING SCARPH

The scarph that connected the stempost to the fore part of the keel was known as the boxing. Like the other keel scarphs, it was lined with tarred flannel before being bolted to the stem.


This section represents the final piece of the keel for my model and was the most difficult to make. I temporarily glued a paper template to the swiss pear blank, then I cut it out with a mini table saw and scroll saw. I sanded the piece to the precise dimensions using a spindle sander and modeler’s files. The box scarph was carved by hand using a small chisel, and then scraped flat with a razor blade. Like the rest of the keel, I lined the boxing with vellum to simulate tarred flannel. 

Cutting the aft part of the keel section. 

Chiseling out the box scarph. 

Finished scarph compared to plans. 

Plain scarph at aft of keel section. 

Gluing the vellum in place. 

Vellum trimmed to fit. 

Finished box scarph. 

Section glued to the rest of keel. 

Wednesday 1 January 2014

LAYING THE KEEL

In September, 1812, around the same time that Napoleon was entering a deserted Moscow on his push to the Kremlin, HMS Terror’s keel was being laid down in Topsham shipyard on the River Exe. Her keel construction exposes much about her design; it incorporated some traits of a merchant vessel of her size (ca. 325 tons), but was generally overbuilt to the standards of much larger ships. The Vesuvius class bomb ships were based on the lines of merchant vessels (Ware 1994:64), but with a much stronger frame to withstand the punishing recoil of the mortars. Sir Henry Peake, Terror’s designer, achieved this sturdiness by incorporating some aspects typically reserved for 36 gun frigates (ca. 1000 tons) and even 74 gun third rates (ca. 1500 tons).

Scantlings for Terror’s Keel:

Sided = 12 and 1/2 inches (consistent with merchant vessel of the same tonnage)

Depth of keel = 1 foot 3 inches (consistent with a small fifth rate frigate)
Number of pieces = 4 (consistent with merchant vessel of the same tonnage)

Scarphs in length = 4 feet (consistent with 36 gun frigate)
Scarph type = plain (with tables)

Lips of the scarphs = 3 inches (consistent with standards for a 12 ½ inch sided keel)
Bolts = 8 (consistent with 76 gun vessel, standard for bomb vessels)

Bolt diameters = 1 and 1/8 inches (consistent with 36 and 74 gun vessels, standard for bomb vessels)
Depth of False keel = 7 inches (thicker than a 74 gun vessel)

The keel of my Terror model is made from swiss pear, with black dyed paper vellum used to simulate the tarred flannel used to line the scarphs in a real vessel. I use acid and lignin free vellum which is both colour stable and dimensionally stable, and takes wood glue very well. As in many model ships, my scarphs aren’t tabled as they won’t be visible when glued.

References:

Ware, Chris.
1994    The Bomb Vessel: Shore Bombardment Ships of the Age of Sail. Naval Institute Press, Annapolis.



Vertical keel scarphs prior to gluing.
Dry fit of keel scarph.
Vellum glued to scarph.
Trimmed vellum on horizontal scarph (stern).

Keel scarph with vellum.

Profile of scarph with vellum.

Gluing the keel sections.
Finished keel section.