10 inch Seacost mortar 1/3 scale

[Double D]

I have decide that the next beer can mortar I build is going to be built to resemble a 10 inch Seacost mortar.  I have been trying to come up with drawings or pictures of this gun to make the tube profile and mortar bed.

I struck a bonanza.


I try to keep the Resource list up to date and was browsing www.civilwarartillery.com  I was going through a page on forts at http://www.civilwarartillery.com/forts/ and noticed the guns listed for Fort Moultrie,Sullivan's Island, SC and Fort Pulaski, Savannah, GA.

There is enough detail in these photos to get measurments and build the gun.  

The next day I got some more news, and offer on my place in Montana...we should be moving out of our son's basement soon where I and set up my tools and get back to work building cannons.

Here's some pictures from that site.



This picture would be better if the gun was square to the camera. From this picture I can get all the measurements for the carriage. I can also get some detail on construction.



This picture gives some real good details on construction.



This adds even more detail.

[Jeff B.]

I wonder what happened to the mortar? Why is it out of it's bed? I'd be an interesting story to hear for sure.

Seems to me there's several of these 10" mortars at the Halifax Citadel. I'll likely bee there again sometime next week (I bought a season pass). If you're interested, I'll take a few pictures for you. I'm pretty sure the bed is of similar design.

[Double D]

If you look real close at that mortar you can see it took a direct hit on the muzzle.

I also noticed those mortars don't have trunnion caps.

[JeffG]

The over  running military forces tipped mortars and cannon out of their carriages to disable them, so they wouldn't incur fire at their back when they left the fort, and have to go do it all over again.  In the case of the seacoast forts or forts overlooking the water channels, the ship captains wanted some assurance that the cannon were definitely done.  Cutting the trunion caps off served the same purpose, as one shot would dislodge the barrel off of the bed or carriage.  It was easier to bury of carry away 20 lbs of metal than mess with a 20,00 lb barrel...faster too.  Often the "vanquished forces" would flee the fort, and hide in the surrounding wilderness, in hopes of coming back to the fort after the advancing forces left, for food scraps, hidden ammunition, water, and supplies.  Wouldn't you take a shot at the guys who just messed up your fort if you had the chance??

[Double D]

...and don't forget the famous spike.  Drive and iron rod down the vent until it bends over and hook inside the bore , then break it off  on the out side.

But in this case it obvious this mortar took a hit on the muzzle!

[Double D]

Got a brillant idea...probably means it won't work.  For the trunnion on my mortar.

I will get a piece of hot roll flat bar 2 by 4. Turn the trunions off center and mill a square groove through the base and weld the Flat bar in the groove.

Be simplier than milling a round groove and then welding fillets and it would look closer to the trunions and fillets found on the actual mortar.

By the way are my eyes deceiving me or do those mortars in the pictures not have trunnion caps?

[Double D]

I got some information today from Paulson Bros on these mortars.
the 10 inch seacoast Pattern 1840  weighed 5575 lbs. had a 91 lb shell.  the bore was 1.25 calibers longs excluding powder chamber and max load was 10 lbs of powder.  

What's the rule of thumb reduce max load by 10% for starting load...

[Calamity Jane]

So yer gonna load 9 Lbs of powder ??!! Shorenuff glad I ain't payin yer powder bill !  :shock:

[Cat Whisperer]

Further, that's 9lbs undet the round and a bunch more inside it!

[Double D]

I think I might figured out the ammo problem.  The bore is 2.6 pop can right now. I think I am going to open up the bore to 3.67 inch and use 6 pounder ball.



I can get them from Paulson Bros for $10 ea plus shipping