Kearsarge Pivot gun tracks - flush to deck or proud?

[alanroy]

Good morning, all, newbie here.

I am building Revell's USS Kearsarge in 1/96th scale. I've come up with a question. I just obtained Scaledecks wooden deck, and they threw in photo-etched pivot gun tracks for the 11" Dahlgrens. 

Would these tracks have been inlet into the deck so as to sit flush, or did they stand proud of the deck? The kit has them sitting barely proud, and the photo-etch would do the same.

Thank you in advance,

Alan

[Keith Black]

 From all the photos I've seen they appear to have sat slightly proud of the deck.

[RichardG]

Here's a couple of other photos. The tracks appear to just laid on the deck. 

 

Photo copyright Alamy - Pivot Gun and Crew, U.S. Ship Pocahontas

 

From www.navalhistory.org

 

[alanroy]

Thank you, Gentlemen! So the photo-etch shouldn't be a problem. I assume they were spiked down somehow.

I forgot to ask whether they were brass or iron. I had always assumed they were brass, because iron rusts. But Blue Jacket (I think) calls out iron.

[RichardG]

They were typically iron. Rust isn't a problem when you've got a bunch guys stuck on a ship with nowhere to go and that have to be kept busy.

[BANYAN]

Hi Richard, they were not necessarily made of iron.  I am researching a ship of the same era with a pivot gun that used sweeps such as these - they were made of gunmetal.  That is not to say they were not iron, they may well have been - need more info I think.

 

Good luck with the build Alan,

 

cheers

 

Pat

[Keith Black]

Pat, in your research have you found anything regarding the sweeps being let into the deck vs just laid flat onto the deck? 

[alanroy]

Thank you again, gentlemen, iron it shall be! Painted black, of course.

[wefalck]

I think they were rather gunmetal (a kind of bronze) or bronze. Although there were surely enough guys to keep them bright on top, they would still rust underneath and begin to discolour the deck planks (kind of chromatography effect). Painting them doesn't make much sense, as the rollers of the guns would peel the paint off quite quickly.

 

I seem to remember that the tracks on HMS WARRIOR were some kind of bronce.

[shipman]

I don't think bronze would have been up to the weight of the gun, especially with the added stress on recoil. My guess is those tracks were hot rolled I-beam steel, let into the deck. Similar stuff was commonly used on rail-roads at that time. Iron would have been too brittle for the same reason. Even then there were grades of iron that didn't rust.

[wefalck]

Guns were cast frome bronze and the rollers for the guns too ... bronze is elastic and wear resistant. The tracks were screwed onto the deck.

[shipman]

Eee, by gum, wefalk. I bow to your assertion. A quick nip over to the Wiki HMS Warrior pages confirms your view. I don't mind being wrong. Still, I'm surprised it was done that way.

[BANYAN]

Keith, as Wefalck has pointed out - gunmetal screwed/fitted to decks.  For HMCSS Victoria they were about 3 inches high according to Douglas (Naval Gunnery 1855) I think, so I have assumed partially embeded.  If I come across the correspondence again, I will post it to you but the ship build supervisor sort of infers this when talking about them. 

 

Shipman, the shore / coastal defence versions of these guns (casement guns) did run on steel or iron rails as the rollers under the slide were more like mini rail wheels, but the ship versions (with a shorter slide and flat rollers) ran on gunmetal as best I can establish.

 

cheers

 

Pat

[Keith Black]

17 minutes ago, BANYAN said:

I will post it to you

Pat, thank you. 

[alanroy]

Hmmm, brass/bronze or iron. I wonder if different countries had different methods.

[wefalck]

In a different context I just looked over my (xerox) copy of an atlas on the Prussian Navy's artillery material, published in 1861. Although still in a nascent stage at that time, it was technologically quite advanced, being kitted out with the latest Krupp breechloading guns. This atlas has drawings for every single part of the guns, their carriages and accessories.

 

The Prussian Navy at that time had as heaviests guns 68-pounder smooth bores and 24-pounder rifled breechloading guns. Both could be mounted in slide carriages of the same type. There is a drawing also for the tracks and these were 9" wide and 1/4" thick to be screwed down onto the deck with countersunk screws, the head of which had about 3/4" diameter. The screws were set 1" from the edge and 13" apart, being offset by half the distance on each side. I only have a b/w copy of the atlas, but in the original the materials were colour-coded in light washes of water colour. As the track appears basically white in the copy, I assume it was light yellow in the original, indicating brass/bronze (or gun-metal) as material for the tracks.

[Roger Pellett]

The Bessemer and Open Hearth technologies to make steel  in commercially available quantities were not available in the United States until after the Civil War.  The first Bessemer plant began production in 1867 and the first Open Hearth process approximately 20 years later in the 1880’s.  In this context, the term “steel” refers to an alloy of iron alloyed with a small (controlled) amount of carbon.

 

Although the Crucible process was available for making steel in small batches it was an expensive material used for special applications.  Much of it would have been imported.

 

Much of what we call “steel” in early America was, therefore, “Iron” in two forms.  Cast iron, a high carbon iron  alloy was used for making products shaped by pouring molten metal into a mold.  Cast iron was unsuitable where the part was subjected to cyclical loads or where the product’s final shape was determined by hot working; forging or rolling.  For these applications, wrought iron was used.  Wrought iron was formed by stirring (puddling) silica slag into a semi molten ball of iron.  When rolled in a rolling mill this produced laminar fibers of slag in a soft iron matrix.  

 

Wrought iron  was a tough, ductile, and, versitle widely used material.  The railroads that supplied the Civil War armies ran on wrought iron rails, and the Confederates cannibalized these to armor their ironclads.  Union ironclads were also armored with wrought iron.  

 

Wrought iron proved also to be an excellent, durable, shipbuilding material proven by the long term survival of the steamship Great Britain.

 

With its availability, durability, and proven ability to withstand heavy rolling loads, I would lean towards its use for these cannon tracks.  American naval engineers were cost conscious, and in a hurry to expand the Union Navy to meet the needs of President Lincoln’s blockade.  Navy ships had large crews with plenty of time on their hands and rust stains could be minimized by a sailor with a holystone.  During war time, navies also tend to forgoe spit and polish to fight.

 

Roger

 

 

 

 

[BANYAN]

Hi again all, Keith, as promised, I have found the reference but had the wrong author.

 

The book 'Naval Gunnery' by Captain H. Garbett, page 66, states that pivot guns were traversed on gun-metal racers (sweeps) secured to the deck.  Note the wording which he uses in his book, which says secured to the deck, NOT into the deck.  This book was first published in 1897, the copy I refer to is the 1971 reprint.

 

Hope this helps.

 

cheers

 

Pat

[Keith Black]

Pat, thank you. Must have been some very long screws to keep the sweeps from shifting under all that weight and movement. I wonder if they weren't through bolted, a slotted counter sunk head on the top side and a nut and washer on the bottom side? 

[wefalck]

My German sources indicate no through-bolting, but just wood-screws. The screws were supposed to be 6" apart. Whether the rails can move depends on how hard the wood is underneath and how well supported the deck planks are.

[Keith Black]

4 hours ago, wefalck said:

My German sources indicate no through-bolting, but just wood-screws. The screws were supposed to be 6" apart. Whether the rails can move depends on how hard the wood is underneath and how well supported the deck planks are.

Thank you, Eberhard. Wood screws must have worked or they would have done something different. That's a testament as to how well the planking was laid down.

 

Barrel weight of the 11 inch Dahlgren was almost 16,000 lbs plus the additional gun carriage and sliding carriage weight would have pushed the total weight to 20,000 lbs. Target practice was held every fortnight or at least once a month. Practice every two weeks would have required moving those beast out 24 times a year and with the journey back to station, would have meant traveling over those screws 48 times a year. I can't find anything regarding sweep inspection/maintenance in the 'Ordnance Instructions for the United States Navy, 1866' but I'm sure there must have been some guide being that it was the Navy. 

[Roger Pellett]

I checked two contemporary sources.  Wilson’s Practial Shipbuilding- 1870 and the 1866 Ordnance  Instructions.  I also checked Arming of the Fleet by Tucker.  Other than a  mention of Deck Circles nothing is said.

 

This lack of information does provide some circumstantial evidence about them.  Wilson’s book discusses bolts securing gun tackles in great detail.  It also includes rules where equipment mounted on deck required mortising of deck structure. These thru hole fasteners and deck modifications were apparently considered to be part of the ship itself and therefore under the jurisdiction of the Bureau of Construction and Repair.  Arming of the completed ship was the responsibility of the Bureau of Ordnance.

 

If the deck circles did not require modification of the ship, there was no need to provide information about them in a shipbuilding text.  This leads me to agree with Wefalk that these deck circles were laid on top of the deck and screwed down  with large flat head wood screws.

 

As a practical matter mortises into the decking and thru bolts would have been a source of leaking and rot.

 

I believe that American practice was wrought iron deck circles laid on top of the deck and secured with large flat head deck screws.

 

Roger

[alanroy]

Hi there,

Sorry to be absent for so long. I’m on vacation, and my iPhone was acting up. Had to finally fire up the iPad. 

Wow, flathead screws, 6” apart. If my math is correct, in 1/96th scale that would be a screw every 1/16th of an inch. Although I highly doubt you would even see them, being countersunk and probably painted black to keep the rust at bay. 

All the best to all y’all,

Alan

[alanroy]

And from the pictures, they appear to be barely thicker than the soles of the shoes of the sailors standing around. 

Back to lunch,

Alan

[BETAQDAVE]

On 9/5/2020 at 12:51 PM, Roger Pellett said:

As a practical matter mortises into the decking and thru bolts would have been a source of leaking and rot.

I would agree with that assesment also.  Another consideration that occurs to me is the fact that wood and metal do not expand or contract at the same rate when reacting to changes in heat or moisture which would more than likely raise hovoc with the edges of the mortices inviting the intrusion of even more moisture.