Ironclads and blockade: Britain vs Union

Fewer ads. Lots of American Civil War content!
JOIN NOW: REGISTER HERE!

USS ALASKA

1st Lieutenant
Forum Host
Joined
Mar 16, 2016
Messages
4,537
I should point out that, although Maitland fretted about 15 20-gun commerce raiders, to arm them would have taken three times as many guns as San Francisco had in reserve.
The statement that Maitland was concerned about 20-24 gunned commerce raiders caught my eye also. If you are outfitting clippers to hunt merchants - do you really need 20 guns? Won't somewhere between 4 and 8 do the trick against the un-armed?

Cheers,
USS ALASKA
 

Dilandu

Sergeant
Joined
Mar 16, 2015
Messages
886
Location
Moscow, Russian Federation
The statement that Maitland was concerned about 20-24 gunned commerce raiders caught my eye also. If you are outfitting clippers to hunt merchants - do you really need 20 guns? Won't somewhere between 4 and 8 do the trick against the un-armed?
Probably even 2-4 would suffice. More than 4 you need only if you supposed to fight the armed opponents.

And hey, where the guns from USS "Independence" disappeared? She was disarmed in 1857 in San Francsisco, so her 50+ guns should still be somewhere around on Mare Island Navy Yard. Of course, she have only 32-pdr, but still pretty suitable for commerce raiders & gunboats.
 

Talos

Corporal
Joined
Aug 15, 2014
Messages
292
Just made some calculation about the comparable fighting power of heavy frigate and average 90-100 gun ship-of-the-line (not counting the super-heavy 120-130 gun liners, of course):

- "Merrimack"-class "heavy" screw frigate: broadside of twelve (12) IX-inch Dahlgrens, seven (7) VIII-inch Dahlgrens and two (2) X-inch pivot Dahlgrens. All have fire rate about one shot per minute. All guns could fire shells & shots.

Total salvo in shells - 12*74 + 7*53 + 2*102 = 1611 pdr

- "Duncan"-class 101-gun screw ship-of-the-line: broadside of eighteen (18) 8-inch shell guns on gun deck, eighteen (18) 32-pdr guns on main deck, fourteen (14) 32-pdr guns and one (1) pivoted 68-pdr shell gun on upper deck. Rate of fire is similar, 1 shot per minute (probably 32-pdr could do best, but not in salvo fire).

Total salvo in shells and shots - 18*51 + (18+14)*32 + 1*68 = 2010 pdr. Of them, only 986 are shells.

Conclusion: the total advantage of average ship-of-the-line over heavy frigate is about 20%. But in shells, the situation is, ship-of-the-line actually have almost 60% disadvantage!

So it seems that the RN's ships-of-the-line even more obsolete than at first look. They could barely fight on even terms the modern heavy frigates (and if weather conditions aren't good, the frigate, with higher gun deck, would probably have deciesive advantage over the low-placed gun deck of the ship-of-the-line). They are faster under steam, thought, so they could probably run away - but for what reason any navy might need the ship-of-the-line whose tactical purpose is to run away from enemy units?!
Minor point, but the upper deck armament on the Merrimack frigates was actually the older 8" shell gun of 63cwt, dating back to the 1840s armament reorganization. It's the American version of the Paixhan gun and the equivalent of the British ML 8-inch shell gun of 65cwt. Dahlgren wanted a big gun upper deck loadout of seven XI-inch pivots on the ships, while most in the Navy wanted the usual mix of 32-pdrs and 8" shell guns. That would have given the ships a broadside weight of 1,960 pounds, only two hundred less than the 120-gun Pennsylvania. They compromised on the main deck IX-inch Dahlgrens for the new frigates and kept the 8" of 63cwt on the upper deck to placate others.

Dahlgren was not pleased with the compromise and he considered it far weakening what the ships could be capable of. He wrote about it in a letter to a friend in the mid 1850s: "I have dislodged the 32-pdrs, and only a few of the old 8" guns find place in the new ships, their batteries being chiefly compposed of my IX-inch and X-inch shell guns. Still the presence of these 8-inch is a blemish and a weakness, and I have yet to get rid of the changes in the structure of the gun which injure their endurance (ed. This is why he did the VIII-inch Dahlgren shell gun)." (Dahlgren, Memoir of John A. Dahlgren, Rear-Admiral United States Navy, page 174)

He was vindicated as a result of the sailing sloop Plymouth's experimental cruise in 1857 armed with 4 x IX-inch Dahlgrens and 1 x XI-inch Dahlgren pivot gun in 1857, proving that the heavy guns could be easily handled at sea. Indeed, during the war, Colorado got refit at one point with 46 x IX-inch Dahlgrens, and an XI-inch Dahlgren and 150-pdr Parrott on her pivots, while Minnesota had the same except four of the IX-inch were replaced with 100-pdr Parrotts.

To illustrate the 8" gun, I am attaching a scaled drawing I made of the 1840s Naval reorganization guns: the structurally-weak 10", three patterns of the 8", the 64-pdr shot gun (equivalent of the British 68-pdr, midway in weight between the 95cwt and 112cwt versions), and the six sizes of the 32-pdr. These are based on official measurement tables, which I transcribed into drawings.

Probably even 2-4 would suffice. More than 4 you need only if you supposed to fight the armed opponents.

And hey, where the guns from USS "Independence" disappeared? She was disarmed in 1857 in San Francsisco, so her 50+ guns should still be somewhere around on Mare Island Navy Yard. Of course, she have only 32-pdr, but still pretty suitable for commerce raiders & gunboats.
Actually, Independence carried a battery of ten of the above-mentioned 8" shell guns of 63cwt on her gun deck too, under Bureau of Ordnance regulations of 1853. Before that (regulations from 1845), she carried 4 x 8" of 63cwt on her gun deck and 4 x 8" of 55cwt on her spar deck.
 

Attachments

Fewer ads. Lots of American Civil War content!
JOIN NOW: REGISTER HERE!

USS ALASKA

1st Lieutenant
Forum Host
Joined
Mar 16, 2016
Messages
4,537
San Francisco alone had more people in 1860 than the entirety of British Columbia and the other British colonies on the Pacific coast did, and more than a fifth of those living in British territory were actually US citizens.
If I remember correctly from Gough, wasn't one of the concerns of the British during the numerous disputes in the NW the great influx of settlers pouring in to the area from the recently opened overland routes? I seem to remember commentary in the book about the perceived threat to the outnumbered British subjects from the American citizens.

Cheers,
USS ALASKA
 

Dilandu

Sergeant
Joined
Mar 16, 2015
Messages
886
Location
Moscow, Russian Federation
Hm! Thank you for the data! Frankly, I was under impression that all US heavy frigates were armed exclusively with Dahlgrens, after "Plymouth" test.

Still, even with old 8-inch guns (I assume they have shell of about 45-50 pdr?) provide enough punch to gave "Merrimack"-class an advantage.

To illustrate the 8" gun, I am attaching a scaled drawing I made of the 1840s Naval reorganization guns: the structurally-weak 10", three patterns of the 8", the 64-pdr shot gun (equivalent of the British 68-pdr, midway in weight between the 95cwt and 112cwt versions), and the six sizes of the 32-pdr. These are based on official measurement tables, which I transcribed into drawings.
Thank you!

Actually, Independence carried a battery of ten of the above-mentioned 8" shell guns of 63cwt on her gun deck too, under Bureau of Ordnance regulations of 1853. Before that (regulations from 1845), she carried 4 x 8" of 63cwt on her gun deck and 4 x 8" of 55cwt on her spar deck.
Hm. So the rest of gun deck was empty in peacetime, or filled with 32-pdr's?
 

67th Tigers

1st Lieutenant
Joined
Nov 10, 2006
Messages
3,658
So it seems that the RN's ships-of-the-line even more obsolete than at first look. They could barely fight on even terms the modern heavy frigates (and if weather conditions aren't good, the frigate, with higher gun deck, would probably have deciesive advantage over the low-placed gun deck of the ship-of-the-line). They are faster under steam, thought, so they could probably run away - but for what reason any navy might need the ship-of-the-line whose tactical purpose is to run away from enemy units?!
I'll make a few points:

1. Height of gun sills and throw weight

The Merrimack had the gun sills a little more than 3 ft 5 inches above the waterline (this is the height of the gun deck) and the Duncan 3 ft with 101 guns (she never carried 101 guns in active service, but instead 89 having the spar deck guns replaced with rifles on pivots*). Less than 5 inches makes little difference, in any sea state where the Duncan can't open her lower deck the Merrimack can't either.

The Merrimack had 24x 9" on the gun deck (12 per side), and 14x 8" (7 per side) and 2x 10" (chasers) on the spar deck. In a calm sea she has a broadside of 12x 9", 7x 8" and 2x 10", and only 7x 8" and 2x 10" in reasonable seas.

The Duncan has 36x 8" on the bottom gun deck, 36x 32 pdrs on the next deck and 1x 12 pdr, 12x 40 pdr, 2x 20 pdr, 1x 110 pdr Armstrongs on the spar deck. In a calm sea she throws 18x 8", 32x 32 pdrs and a 68 pdr, and in a sea state that closes the lower gun deck 32x 32 pdrs and the Armstrongs can still engage.

* Her spar deck in 1862 had the following Armstrongs: 1x 12 pdr, 2x 20 pdr, 1x 110 pdr, 12x 40 pdr, all capable of firing both sides.

The throw weight is thus:

All decks
Merrimack: 1,424 lbs
Duncan: 1,970 lbs

Sea state
Merrimack: 551 lbs
Duncan: 1,154 lbs

2. "Armour"

The Duncan was 36" oak walls, the Merrimack 24" of oak and pine (which is much weaker).

The Duncan is "immune" even to the 10", which only penetrated 32" of oak at 500 yds at the normal. The weaker armour of the Merrimack wouldn't stop the long 32's at 1,000 yds and the heavy 8" will also penetrate at 1,000 yds. The rifles of course are effective at several thousand yards.

Thus in a calm sea at 1,000 yds, the effective throw weight is:
Merrimack- throw weight of effective rounds against Duncan: 0 lbs
Duncan - visa versa: 1,970 lbs

3. Speed

Merrimack under steam typically made 6 kts, and her greatest every speed under steam was 9.5 kts (unloaded with a following wind and with tide. Duncan made 13.3 kts on standard trials at Stokes Bay with 101 guns (average of 6 runs, both directions to cancel out wind and tide effects). In a sea state the Merrimack looses speed quicker than Duncan.
 
Fewer ads. Lots of American Civil War content!
JOIN NOW: REGISTER HERE!

USS ALASKA

1st Lieutenant
Forum Host
Joined
Mar 16, 2016
Messages
4,537
Were there any useable, British controlled, overland routes to the NW like the Oregon Trail? Was the York Factory Express trade route able to support operations?

Thanks,
USS ALASKA
 

Talos

Corporal
Joined
Aug 15, 2014
Messages
292
Hm! Thank you for the data! Frankly, I was under impression that all US heavy frigates were armed exclusively with Dahlgrens, after "Plymouth" test.

Still, even with old 8-inch guns (I assume they have shell of about 45-50 pdr?) provide enough punch to gave "Merrimack"-class an advantage.



Thank you!



Hm. So the rest of gun deck was empty in peacetime, or filled with 32-pdr's?
The rest is filled with 32-pdrs, 57cwt long guns on the gun deck, and (since Independence is one of the largest sailing frigates in the USN), 42cwt guns on the spar deck instead of the usual 32cwt guns. The final ones are a pair of 51cwt chase guns in the "forecastle". The 8" shell for the gun weighs about 53.75 pounds, with a 1.85lb bursting charge.

I'll make a few points:

1. Height of gun sills and throw weight

The Merrimack had the gun sills a little more than 3 ft 5 inches above the waterline (this is the height of the gun deck) and the Duncan 3 ft with 101 guns (she never carried 101 guns in active service, but instead 89 having the spar deck guns replaced with rifles on pivots*). Less than 5 inches makes little difference, in any sea state where the Duncan can't open her lower deck the Merrimack can't either.

The Merrimack had 24x 9" on the gun deck (12 per side), and 14x 8" (7 per side) and 2x 10" (chasers) on the spar deck. In a calm sea she has a broadside of 12x 9", 7x 8" and 2x 10", and only 7x 8" and 2x 10" in reasonable seas.

The Duncan has 36x 8" on the bottom gun deck, 36x 32 pdrs on the next deck and 1x 12 pdr, 12x 40 pdr, 2x 20 pdr, 1x 110 pdr Armstrongs on the spar deck. In a calm sea she throws 18x 8", 32x 32 pdrs and a 68 pdr, and in a sea state that closes the lower gun deck 32x 32 pdrs and the Armstrongs can still engage.

* Her spar deck in 1862 had the following Armstrongs: 1x 12 pdr, 2x 20 pdr, 1x 110 pdr, 12x 40 pdr, all capable of firing both sides.

The throw weight is thus:

All decks
Merrimack: 1,424 lbs
Duncan: 1,970 lbs

Sea state
Merrimack: 551 lbs
Duncan: 1,154 lbs

2. "Armour"

The Duncan was 36" oak walls, the Merrimack 24" of oak and pine (which is much weaker).

The Duncan is "immune" even to the 10", which only penetrated 32" of oak at 500 yds at the normal. The weaker armour of the Merrimack wouldn't stop the long 32's at 1,000 yds and the heavy 8" will also penetrate at 1,000 yds. The rifles of course are effective at several thousand yards.

Thus in a calm sea at 1,000 yds, the effective throw weight is:
Merrimack- throw weight of effective rounds against Duncan: 0 lbs
Duncan - visa versa: 1,970 lbs

3. Speed

Merrimack under steam typically made 6 kts, and her greatest every speed under steam was 9.5 kts (unloaded with a following wind and with tide. Duncan made 13.3 kts on standard trials at Stokes Bay with 101 guns (average of 6 runs, both directions to cancel out wind and tide effects). In a sea state the Merrimack looses speed quicker than Duncan.
The port height is wrong. Even Niagara post-refit (the worst of the bunch) had her midships port 5'6" above the waterline. You can see on this picture of Colorado that the gunports are far more than three feet above the top of the coppering. http://www.museumsyndicate.com/images/8/76128.jpg

On point 2, you might be thinking of the older, weaker 10" shell gun from the 1840s, which was dramatically underpowered. The Dahlgren had three times the powder charge as it (12.5lbs versus 4lbs), yet scarcely better penetration than a Napoleonic 18-pdr?

With point 3 you are correct, that is the largest weakness of the ships. They were horrifically slow.
 

Dilandu

Sergeant
Joined
Mar 16, 2015
Messages
886
Location
Moscow, Russian Federation
The rest is filled with 32-pdrs, 57cwt long guns on the gun deck, and (since Independence is one of the largest sailing frigates in the USN), 42cwt guns on the spar deck instead of the usual 32cwt guns. The final ones are a pair of 51cwt chase guns in the "forecastle". The 8" shell for the gun weighs about 53.75 pounds, with a 1.85lb bursting charge.
Thank you for clarification.
 
Fewer ads. Lots of American Civil War content!
JOIN NOW: REGISTER HERE!

67th Tigers

1st Lieutenant
Joined
Nov 10, 2006
Messages
3,658
The port height is wrong. Even Niagara post-refit (the worst of the bunch) had her midships port 5'6" above the waterline. You can see on this picture of Colorado that the gunports are far more than three feet above the top of the coppering. http://www.museumsyndicate.com/images/8/76128.jpg
The number I had easily to hand for both ships was the height of the gundeck above the waterline. I was simply showing that the lower gundeck of the Duncan was the same height as the only gundeck of the Merrimack. The Sills themselves will be a few feet higher.

On point 2, you might be thinking of the older, weaker 10" shell gun from the 1840s, which was dramatically underpowered. The Dahlgren had three times the powder charge as it (12.5lbs versus 4lbs), yet scarcely better penetration than a Napoleonic 18-pdr?
I take your point. The chasers are 107 cwt 10" instead of 86 cwt pieces, and used a 12.5 lb instead of a 10 lb charge. However, whilst I don't have a table to hand I can calculate by multiplying through that at 1,000 yds the Dahlgren 10" would have a penetration of about 30" of oak instead of 24" for the older gun. That's still not enough against Duncan's sidewalls. The 10 " will become effective at around 7-800 yds range, the 9" will become effective around 400 yds, and the 8" much less.

Against a weaker target of course these numbers are much greater. Against a frigate of 24" the 8" is effective about 7-800 yds, the 9" about 1,000 - 1,100 yds and the new 10" about 1,200 yds (the old one 1,000 yds). Against sloops etc. the range of course lengthens considerably.

Which is why a lot of these auxiliary gunboats could end up being one-shoted from several miles away. Their saving grace against time-fused shells is that the round would likely zip them and exit the far side before exploding, but the British had the Moorsom fuse for their shell guns (a percussion fuse that produced a reliable detonation inside the enemy 90% of the time) and the pillar fuse for the Armstrongs (which aside from a small batch of faulty fuses that accidently got sent to the fleet were extremely effective).
 

Dilandu

Sergeant
Joined
Mar 16, 2015
Messages
886
Location
Moscow, Russian Federation
Maybe I don't understand something, but why the shell (explosive shell) need to go through wooden side, to make damage? The detonation of the shell, deepened into the wood seemingly would have even more destructive effect; we would have gaping hole in the side of the liner, and buckshot of splinters inside the hull.

So all this "would penetrate only 20 inches... would not penetrate 32 inches"... What's the meaning of this? If the shell would penetrate only 12 inches, it would still be inside the wood in the moment of detonation, and would ripe several square feets of ship's side apart.

Or have I missed something?
 

Talos

Corporal
Joined
Aug 15, 2014
Messages
292
The number I had easily to hand for both ships was the height of the gundeck above the waterline. I was simply showing that the lower gundeck of the Duncan was the same height as the only gundeck of the Merrimack. The Sills themselves will be a few feet higher.



I take your point. The chasers are 107 cwt 10" instead of 86 cwt pieces, and used a 12.5 lb instead of a 10 lb charge. However, whilst I don't have a table to hand I can calculate by multiplying through that at 1,000 yds the Dahlgren 10" would have a penetration of about 30" of oak instead of 24" for the older gun. That's still not enough against Duncan's sidewalls. The 10 " will become effective at around 7-800 yds range, the 9" will become effective around 400 yds, and the 8" much less.

Against a weaker target of course these numbers are much greater. Against a frigate of 24" the 8" is effective about 7-800 yds, the 9" about 1,000 - 1,100 yds and the new 10" about 1,200 yds (the old one 1,000 yds). Against sloops etc. the range of course lengthens considerably.

Which is why a lot of these auxiliary gunboats could end up being one-shoted from several miles away. Their saving grace against time-fused shells is that the round would likely zip them and exit the far side before exploding, but the British had the Moorsom fuse for their shell guns (a percussion fuse that produced a reliable detonation inside the enemy 90% of the time) and the pillar fuse for the Armstrongs (which aside from a small batch of faulty fuses that accidently got sent to the fleet were extremely effective).
I'm away from my computer, typing on my phone right now, but I can make a few remarks.

The old failed 10" gun was the Paixhans of 86cwt. It was already replaced by the time the steam frigates came in service. If you look up the range table for it in Dahlgren's shell gun book, it is struck through. That one had dramatically poor penetration, the true penetrater was the 64 pounder shot gun of 106cwt.

With regards to the gun port height, remember that there is a complete unarmed deck below the gun deck that is almost entirely above the waterline. Indeed I found an 1857 publication of the Franklin Institute on Google Books that cites 9 feet amidships and 12 feet at either end, more that enough to fight the guns in bad weather. This matches the photo of Colorado too.

Edit: Here is a period drawing that illustrates the deck below the deck. This is actually called the gun deck, possibly the source of the confusion. The guns are on the upper deck and the spar deck above it.
http://t0.gstatic.com/images?q=tbn:ANd9GcTicvru4mZzJVa4C52_4NhdnfkDUROpPovAqs5rExUTnjcigizT
 
Last edited:
Fewer ads. Lots of American Civil War content!
JOIN NOW: REGISTER HERE!

67th Tigers

1st Lieutenant
Joined
Nov 10, 2006
Messages
3,658
Or have I missed something?
Yes, you have.

The expanding gases follow the path of least resistance. If partially through the hull they will vent outwards (through the partial hole it has made) and have no effect on the interior.

To have a destructive effect the shell needs to explode inside the target.

BTW, gunpowder does not detonate, it deflagrates (burns).
 

67th Tigers

1st Lieutenant
Joined
Nov 10, 2006
Messages
3,658
I'm away from my computer, typing on my phone right now, but I can make a few remarks.

The old failed 10" gun was the Paixhans of 86cwt. It was already replaced by the time the steam frigates came in service. If you look up the range table for it in Dahlgren's shell gun book, it is struck through. That one had dramatically poor penetration, the true penetrater was the 64 pounder shot gun of 106cwt.
The one linked to twice by me in the last couple of hours?

With regards to the gun port height, remember that there is a complete unarmed deck below the gun deck that is almost entirely above the waterline. Indeed I found an 1857 publication of the Franklin Institute on Google Books that cites 9 feet amidships and 12 feet at either end, more that enough to fight the guns in bad weather. This matches the photo of Colorado too.
That would be the design height? Merrimack was several feet deeper than intended when launched. The CSS Virginia was about 3 feet lighter and her ports were 7 feet above the waterline. As I said, to hand was only the height of the deck above the waterline, and for both Merrimack and Duncan they are similar, and hence Dilandu's assertion that there were sea states where the Duncan couldn't use her lower GD but Merrimack could is essentially false.

There were situations where this could occur, and the most famous is HMS Indefatigable against the French Droits de l'Homme, but the Indie was a razee with unusually high sills, and the DdlH's lower GD were 14 inches lower than standard.
 

Dilandu

Sergeant
Joined
Mar 16, 2015
Messages
886
Location
Moscow, Russian Federation
The expanding gases follow the path of least resistance. If partially through the hull they will vent outwards (through the partial hole it has made) and have no effect on the interior.
W...T...H...?

So, in your opinion the gases that was able to tear apart the cast-iron shell of the projectile would be unable to tear the wood? You think the bomb is like a kettle?!

The hole have NO EFFECT. At all. We already have the shockwave, formed by the bomb shell. This is the whole point of having the shell around the explosive, for Pete's sake! The wood only recieve the already wformed shockwave - and the wood is notoriously bad against shockwaves!

The actual effect from the bomb detonation inside the ship side would be even more powerfull, actually. Because the wood outside the bomb casting would slow the casting expansion, and more of powder charge would be able to burn.

Tiger, be honest - you have absolutely no clue about explosives at all? You didn't even knew how the shockwave is formed? You absolutely did not understand, for what reason the shells have the outer shell?
 
Fewer ads. Lots of American Civil War content!
JOIN NOW: REGISTER HERE!

Talos

Corporal
Joined
Aug 15, 2014
Messages
292
The one linked to twice by me in the last couple of hours?



That would be the design height? Merrimack was several feet deeper than intended when launched. The CSS Virginia was about 3 feet lighter and her ports were 7 feet above the waterline. As I said, to hand was only the height of the deck above the waterline, and for both Merrimack and Duncan they are similar, and hence Dilandu's assertion that there were sea states where the Duncan couldn't use her lower GD but Merrimack could is essentially false.

There were situations where this could occur, and the most famous is HMS Indefatigable against the French Droits de l'Homme, but the Indie was a razee with unusually high sills, and the DdlH's lower GD were 14 inches lower than standard.
I was just providing some additional background on the gun and since you had brought up the book, I included that reference to it.

The source I had for the gun port heights specified that was the loaded weight, several years after the ship was commissioned. The gundeck was the unarmed deck below it and even the was just about clear of the water.
 

67th Tigers

1st Lieutenant
Joined
Nov 10, 2006
Messages
3,658
W...T...H...?

So, in your opinion the gases that was able to tear apart the cast-iron shell of the projectile would be unable to tear the wood? You think the bomb is like a kettle?!

The hole have NO EFFECT. At all. We already have the shockwave, formed by the bomb shell. This is the whole point of having the shell around the explosive, for Pete's sake! The wood only recieve the already wformed shockwave - and the wood is notoriously bad against shockwaves!

The actual effect from the bomb detonation inside the ship side would be even more powerfull, actually. Because the wood outside the bomb casting would slow the casting expansion, and more of powder charge would be able to burn.
Shockwaves? This is gunpowder, and the speed of burning is subsonic and so does not generate a shockwave. That's the difference between a low explosive (like gunpowder) and a high explosive (like guncotton).

It's fairly clear you have little idea how explosions work, but gunpowder acts quite differently to lyddite etc.. Gunpowder does not detonate (which is supersonic burning), it deflagrates (burns). If contained the pressure will build up until it breaks the container or vents elsewhere (such as down a gun barrel). With a shell half buried in a hull the pressure will vent outside, because that's the path of least resistance. To have a destructive effect against the interior spaces the shell must be inside the target when it explodes, so the pressure is released inside rather than outside the ship.
 

67th Tigers

1st Lieutenant
Joined
Nov 10, 2006
Messages
3,658
I was just providing some additional background on the gun and since you had brought up the book, I included that reference to it.

The source I had for the gun port heights specified that was the loaded weight, several years after the ship was commissioned. The gundeck was the unarmed deck below it and even the was just about clear of the water.
Ah, that's the Niagara, not the Merrimack isn't it? She had an empty gundeck below the spar deck, and all the armament (12x 11") on the spar deck (5 each broadside and 2 pivots). They tried filling that gundeck in 1863, but she ran so deep the gunports couldn't have been opened in a seaway and abandoned the idea.

At the waterline in naval architecture was the orlop deck (the waterline being between the deck and ceiling of that deck). Above the orlop deck were the gundeck(s).
 
Fewer ads. Lots of American Civil War content!
JOIN NOW: REGISTER HERE!

Talos

Corporal
Joined
Aug 15, 2014
Messages
292
Ah, that's the Niagara, not the Merrimack isn't it? She had an empty gundeck below the spar deck, and all the armament (12x 11") on the spar deck (5 each broadside and 2 pivots). They tried filling that gundeck in 1863, but she ran so deep the gunports couldn't have been opened in a seaway and abandoned the idea.

At the waterline in naval architecture was the orlop deck (the waterline being between the deck and ceiling of that deck). Above the orlop deck were the gundeck(s).
No, the gun deck (in name only) on all frigates are unarmed, a remnant when they were small two-deckers. The Royal Navy is the one that started that naming convention. The gun decks on the Merrimack were the upper deck and the spar deck, with an identical unarmed gundeck as Niagara was built. Niagara had one less deck, just the spar deck where the pivots were mounted. The or lop on all frigates and liners is a small half deck right above the hold where the cockpit, magazines, and sickbay were located safe below the waterline.
 

Dilandu

Sergeant
Joined
Mar 16, 2015
Messages
886
Location
Moscow, Russian Federation
With a shell half buried in a hull the pressure will vent outside, because that's the path of least resistance.
For Lenin's sake, why the 9-inch shell, capable of penetrating the 20 inches of wood would be half-buried?! She would be just simply buried, while not penetrating through! The whole energy of gases would be contained inside the wood; the damage to the construction would be excessive!

(While I must admit, that the "shockwave" is not the best therm to describe the inside-material effect of black powder, but personally I was quite shocked by this "explosive theoteric"!)
 
Fewer ads. Lots of American Civil War content!
JOIN NOW: REGISTER HERE!
Top