Mortar Raft clarifications

graught

Cadet
Joined
Apr 16, 2019
Mortar Raft.jpg


I am doing an image of the shelling of Island No 10. I did not reuse my mortar raft from my Arkansas image as I learned that it's just not correct so I wanted to make a version that was as correct as possible. There seems to be all sorts of opinions as to how these looked. I am basing my current model on the one in the image here. I am going with the round rotating platform for two reasons. First, personally I find it the more appealing in the absence of absolute certainty. Secondly, the drawings have most pointed straight ahead and a few have the mortar firing over the sides. In the photo, there is one straight ahead and the one on the raft in the back (red circle) is pointing sideways. I realize that these are probably getting dismantled and that's why they are in the current state and may have nothing to do with how they were originally made.
These are most likely the 2nd "Porter" version. They have the rounded deck and I was going with the flat ends. I can do either since it is no big deal to swap out the decks. I'm not terribly concerned with the draft even though it seems to range from 4 or 5 to 7. The Simplot sketch of the rafts being built has the deeper draft. I read the deal where the "drop down" doors at the stern were blown off but I was just going with the swinging doors towards the middle and sliding panels for the sides. Again I can switch that pretty easily on the model. I am speculating that the wire in the photo ( blue circle ) that goes all the way around the top was for something to hold onto while moving around outside of the casemate. It's also bent and the end there where a person might grab it and use it to swing their way back into the opening there. It seems too stiff to be rope but I had not seen that addition before.
Additionally, the sketches all seem to show close fitting metal planks for the sides but these appear to be larger plates riveted together with additional seams added to the openings at the front, rear and the four corners. The artists cant all be wrong but the photo says something else.

Thanks for any insight you can provide. I am probably over-thinking this project but I want it to be as correct as possible.
 
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Joined
Sep 28, 2013
Location
Southwest Mississippi
I wish I could add something, but I can't.

I know nothing about mortar rafts. But I've always found such weapons interesting.

Honestly, I thought those rafts were only floating wooden platforms for a single heavy mortar, with the iron sidings constructed to protect the crew from small arms fire. I had no idea such rafts had a rotating platform.

While I can easily visualize a rotating platform on a mortar schooner, I never knew a mortar raft had such mechanisms.

Anyway, please post some images of your finished model.
 
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graught

Cadet
Joined
Apr 16, 2019
I wish I could add something, but I can't.

I know nothing about mortar rafts. But I've always found such weapons interesting.

Honestly, I thought those rafts were only floating wooden platforms for a single heavy mortar, with the iron sidings constructed to protect the crew from small arms fire. I had no idea such rafts had a rotating platform.

While I can easily visualize a rotating platform on a mortar schooner, I never knew a mortar raft had such mechanisms.

Anyway, please post some images of your finished model.
I will post something when I get comfortable with the model. Yes, the rotating platform is a weird unicorn. It would seem like the tackle necessary to turn it would be a health hazard especially if you were trying to load it with that heavy shot.
 

georgew

First Sergeant
Joined
Oct 1, 2010
Location
southern california
I wish I could add something, but I can't.

I know nothing about mortar rafts. But I've always found such weapons interesting.

Honestly, I thought those rafts were only floating wooden platforms for a single heavy mortar, with the iron sidings constructed to protect the crew from small arms fire. I had no idea such rafts had a rotating platform.

While I can easily visualize a rotating platform on a mortar schooner, I never knew a mortar raft had such mechanisms.

Anyway, please post some images of your finished model.
I'm with you, I'd never heard of these rotating mounts before, but they make sense. When Gen. Jeff Thompson was informed that Fort Pillow was to be abandoned and that he and Capt. Montgomery, senior of the Northern Squadron of the RDS were now in charge of slowing down the advance of Union vessels down the river, he replied that Montgomery needed to defend at every choke point. He also wanted any Confederate mortars at Pillow to be saved. The idea was to put them on rafts and use them from behind islands or bars in the river to harass the Union steamers and slow them down. I'm guessing that some lucky steamer crew like the Little Rebel would be stuck out in stream to observe the fall of shot and signal changes. Your depiction of a mortar rotating mount makes me think this was a pipe dream. Without such a mount you can't vary your fire and the darn things were so heavy I wonder how they could be mounted on an improvised raft, assuming that a raft or a coal barge was available. In any case, the Union fleet moved down river so rapidly there was no time for such improvisions.
 

lelliott19

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I don't know enough to be of any help whatsoever but like @7th Mississippi Infantry I have always been fascinated with mortar rafts. Here's a link to an article that appeared in the The Weekly Sun. (Columbus, Ga.), July 08, 1862, page 3., reprinted from the Richmond Enquirer of June 28, 1862 about "raft batteries" with iron sides on the Pamunkey River in Virginia during the Seven Days.
https://civilwartalk.com/threads/un...ey-river-va-june-26-1862.152339/#post-1941786
Further down in the same thread is a patent drawing for A B Cooley's Floating Battery, patented April 1, 1861. https://civilwartalk.com/threads/un...ey-river-va-june-26-1862.152339/#post-1941875
I can't wait to see your finished model!
 
Joined
Sep 28, 2013
Location
Southwest Mississippi
I'm with you, I'd never heard of these rotating mounts before, but they make sense.
Thanks !

I've only seen one of these from the Vicksburg campaign.
It appears to be one of the heavy "sea coast" mortars (hastily) placed on a protected raft.

That mortar is on display at the Grand Gulf Military Park about 20 miles south of Vicksburg. Seems it was on a mortar raft that was sunk during the War, and recovered during the early 1900's.

James N. posted a great image of this weapon :


DSC06789.jpg


https://civilwartalk.com/threads/the-dictator-a-13-inch-seacoast-mortar.168351/

That mortar is massive !

I doubt the mortar rafts at Vicksburg had a rotating platform.
It seems the US Navy worked wonders just to construct wooden rafts (under the circumstances) to support the weight of such mortars ... much less float such ordnance.

But as I said, I have no idea if the weapons could rotate.
 
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Lampasas Bill

Sergeant
Joined
Sep 24, 2018
After I retired from the Missouri Department of Natural Resources, I worked on contract to research and write copy for Civil War historical markers. One was about the Eads Boatyard in St. Louis. In addition to a number of ironclads, Eads also built the mortar rafts used by Admiral Porter at Vicksburg. Whether they had rotating mortar platforms I cannot say, but it makes sense that they did to allow the mortars to stay on target or to switch targets if necessary without having to reposition the raft. Eads would have had the capability to do so. Just my two cents worth...
 

7thWisconsin

Sergeant Major
Joined
Nov 21, 2014
I don´t know anything about the boat construction, but apparently duty on them was hard on the mortar crew. Standing close to the gun while firing was hard on the inner ear. After the war, their balance was all messed up and they were noted for a peculiar rocking back and forth behavior.
 

BarkJuice

Cadet
Joined
Dec 30, 2020
Location
Superstition Mountains
Like many here, I’ve had an interest in CW mortar rafts for many years. Over the years I’ve collected a few photos and woodcuts about them, but few indicate that a rotating mortar base was used. Below is the only one I have which hasn’t been posted. An assumed contemporary woodcut doesn’t prove anything, journalists haven’t improved their accuracy any since the mid-19th century, but it is one data point. Hopefully this helps the OP, at least a little.

10C0E556-5D58-4E78-B98E-560CD55F6CE7.jpeg
 

graught

Cadet
Joined
Apr 16, 2019
Like many here, I’ve had an interest in CW mortar rafts for many years. Over the years I’ve collected a few photos and woodcuts about them, but few indicate that a rotating mortar base was used. Below is the only one I have which hasn’t been posted. An assumed contemporary woodcut doesn’t prove anything, journalists haven’t improved their accuracy any since the mid-19th century, but it is one data point. Hopefully this helps the OP, at least a little.

View attachment 396493
Thanks!
 

graught

Cadet
Joined
Apr 16, 2019
Here is the shaded wireframes of where I am at the moment on this. 10degrees slope on the 3/8ths thick walls. Mortar pegged at 41 degrees. 22 feet at the ends and 25 in the middle. 65 feet long. Hopefully, if things calm down in my life I can finish the hull and move on. If anyone is not using their time machine this weekend, I'd love to borrow it so I can see one of these things up close and personal like.

pic1.png


pic2.png


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