Coehorn Mortar

MAPMFF · Sep 22, 2023

Acquired this earlier in the summer, but just now getting around to sharing.

Randomly on a FB marketplace I found this being sold a town away. Took a ride, managed to talk the seller down a bit and made the deal.

Got it back home, these were the photos from when I backed into my driveway. This piece was cast by LaPan and is about 3.75" on the bore with a smaller powder chamber. This most closely resembles the 4.6" in use by the British and those copied and captured by the Americans during the Revolutionary War. This one sat for quite a while as you can see by the condition of the bed. I've since began to rehab the bed.

My new artillery reenacting group is, at first going to be centered around a 3 pounder, but we'll bring this along for demonstration, education etc.

More photos to follow.

MAPMFF · Sep 22, 2023

Got to work on it as soon as I could, got the mortar itself up and out of the bed, which I don't think it had ben in some time.

Also you can see the scale, the mortar weighed in at 76.8 and the bed was 75 pounds even.

MAPMFF · Sep 22, 2023

Decided I wanted to start again on the patina, and also give a good clean up to check for any imperfections, or anything that may have been concerning that was not readily visible to the eye. A good workover with some 000 and 0000 steel wool, brasso and flitz had this thing looking great.

MAPMFF · Sep 22, 2023

Took to sanding the bed, what a mess, multiple coats over the years (to be expected) but some good wood underneath.

Can see there were all sorts of imperfections and a large crack running down the middle.

MAPMFF · Sep 22, 2023

Original beds are one piece and made of oak. This one appears to be pine.

This one appeared to be one piece, hard to tell if the horizontal line you can see more clearly in the photo above is a natural long running imperfection or if they had tried to laminate a few chunks together. It is to the regulation size of 28.5" x 14" x 9"

I had gotten a few ideas from a local saw mill, and may eventually replace the bed with white oak, but for the cost, I wanted to see if I could get this one up to snuff for reenacting. I did some googling and came across a product called Goodfilla Wood Filler, and it's good on small to big cracks, a thick putty. It worked really well as you can see in some of the areas I have already sanded. Filled in knots and cracks without issue and sanded smooth.

MAPMFF · Sep 22, 2023

I don't have a picture of all the cracks filled and sanded but it was a muti day process the wood filler advised that to fill deep cracks to go 1/4" at a time to allow for proper drying. But it came out great. Gave it a coat of primer:

MAPMFF · Sep 22, 2023

And finally after sanding the ammo box that it came with, they both were primed and painted with an appropriate mix of white/black oil based paints to achieve a lead grey color that British artillery was painted at the time.

MAPMFF · Sep 22, 2023

This is an example of a British 4.5" coehorn mortar in the Royal Armories Collection in the UK. This is what we will be replicating. For those of you with attention to detail you'll notice that my capsquares are rounded and the trunion of the mortar is partially visible whereas in the original example pictured here the capsquares are flat and the mortar is sunken into the bed deeper. For now that will be the one thing I'll let myself live with, that will be a future project to sink the tube in more to allow for proper capsquares. The rest of the hardware will be as pictured here, new hand-forged carry handles and chains. After that I'll tie rope to replicate what is seen here, though it is hard to tell if the rope in this image was perhaps coated with something, tar, etc. like some maritime ropes were or if the darkening is a byproduct of its age..

More to come when I get the hardware installed.

lostsmenfive · Sep 22, 2023

Great post - Thanks.

fjrdoc · Sep 23, 2023

Nice read on a subject that I know nothing about.

ColonialRifleSmith · Sep 23, 2023

MAPMFF said:
Acquired this earlier in the summer, but just now getting around to sharing.

Randomly on a FB marketplace I found this being sold a town away. Took a ride, managed to talk the seller down a bit and made the deal.

Got it back home, these were the photos from when I backed into my driveway. This piece was cast by LaPan and is about 3.75" on the bore with a smaller powder chamber. This most closely resembles the 4.6" in use by the British and those copied and captured by the Americans during the Revolutionary War. This one sat for quite a while as you can see by the condition of the bed. I've since began to rehab the bed.

My new artillery reenacting group is, at first going to be centered around a 3 pounder, but we'll bring this along for demonstration, education etc.

More photos to follow.

Nice. Question. why did they call it a Mortar?

BillinOregon · Sep 23, 2023

It's clear this beast found the right home. Really look forward to your continuing adventure and hope to see it fired.

Josh Canuck · Sep 23, 2023

ColonialRifleSmith I wouldn't bet my life on it but I'd think it is because of the resemblance it has (short ans stubby) with an apothicary mortar used to grind herbs etc in to make medecines.

MAPMFF · Sep 23, 2023

ColonialRifleSmith said:
Nice. Question. why did they call it a Mortar?

Josh Canuck said:
ColonialRifleSmith I wouldn't bet my life on it but I'd think it is because of the resemblance it has (short ans stubby) with an apothicary mortar used to grind herbs etc in to make medecines.

Correct, as I understand it the term come from the old French term for a short cannon "Mortier" derived from a bowl for mixing or pounding.

The Coehorn portion of the term comes from the inventors name, Menno, Barorn van Coehorn who was a prominent officer and engineer in the Dutch military in the 17th & 18th Centuries and invented this version of mortar in and around 1700/1701

MAPMFF · Sep 23, 2023

BillinOregon said:
It's clear this beast found the right home. Really look forward to your continuing adventure and hope to see it fired.

Thank you! I hope so, got to take care of this stuff, even though its not original, still worth preserving by the best means and getting it as close to accurate as possible for use in reenactments and educational displays. I always say if something is worth doing its worth doing right.

hawkeye2 · Sep 23, 2023

I have never seen an example of a barrel bound to the base as in your photo but I would imagine that the rope had been tared.

Poguetx · Sep 23, 2023

I shoot mine occasionally on New Year's and 4th of July. It's one like Dixie Gun Works sells - cast iron with steel liner. I built a reducing insert that holds an amount of powder equal to a 35mm film canister - probably about 250 grains. Fires a racquet ball out of site.

I'd love to see a pic of yours firing with a full charge!

No need for comments about the equipment being too close - y'all chided me enough when I posted this year's ago!

sheriff john · Sep 23, 2023

Interesting stuff. Thanks.

ColonialRifleSmith · Sep 23, 2023

WOW, thanks for the answer, guys. Appreciated. Semper Fi.

Jay Templin · Sep 23, 2023

At my first museum we did our artillery demos with a LaPan six-pounder. Their guns are top notch, and your restoration looks great!
Jay

Coehorn Mortar

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ColonialRifleSmith I wouldn't bet my life on it but I'd think it is because of the resemblance it has (short ans stubby) with an apothicary mortar used to grind herbs etc in to make medecines.​

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ColonialRifleSmith I wouldn't bet my life on it but I'd think it is because of the resemblance it has (short ans stubby) with an apothicary mortar used to grind herbs etc in to make medecines.

ColonialRifleSmith I wouldn't bet my life on it but I'd think it is because of the resemblance it has (short ans stubby) with an apothicary mortar used to grind herbs etc in to make medecines.