Building Mortar Boats
Updated: Dec 28, 2021
One of the interesting little innovations of the US Navy during the Civil War was the mortar boats (sometimes called rafts). These were essentially small, unpowered platforms that could carry a single powerful13" mortar. These would be brought close to the action by towboats, lashed to the shore, and bombard rebel strongholds. They were particularly useful at places like Island No. 10, Fort Pillow, and Vicksburg, and many other similar sieges. They were only 60x25ft (18.5 x 7.6m) and surrounded by a bulletproof 6ft high iron wall to protect the 13-man crew.
After looking into the Battle of Plum Point Bend, I found that Mortar Boat No. 16 played the inciting role as the rebel rams came out to dispatch the annoying raft. The mortar was quickly defended by a few ironclads, resulting in a pitched battle. I don't have a mortar boat in my collection, so I decided to make some! So here's a quick how-to guide for making mortar boats.
Above: I considered making the whole thing out of balsa, as usual. However, I felt like the making open-top rafts would be a bit tricky to mass-produce, especially since I wanted to make a half-dozen. So I decided to try something new and make a papercraft casemate out of cardstock. I tried some prototypes to make sure I had the angles right. Once I was happy with the result I made up a plan.
Above: I made up a bunch of different options and templates and added some reference photos.
Above: I cut out six armored casemates, taking care to lightly score the fold lines. I then wrapped them around and superglued the ends together to complete the casemate.
Above: I cut the rafts out of 1.5mm balsa and then used a hole punch to make six platforms for the mortars out of the same card I used for the casemate.
Above: I glued the platforms in the center of the rafts.
Above: I made the mortars out of a bamboo skewer. Before I cut the mortar off the stick, I sanded the end into a rounded shape. Then I sliced off six mortars.
Above: To make the mortar's carriage, I sanded six grooves into the corner of a scrap piece of balsa. I glued the mortars into the groove.
Above: I trimmed the wood back and then cut the mortars apart.
Above: Next I glued all the mortars on the platforms.
Above: I painted the inside of the casemates grey.
Above: After painting the platform and mortars, I then glued the casemates on top.
Above: Finally, I painted the top of the casemates with a gunmetal and added a small dot of black for the muzzles.
And that's that! If you're interested in trying this out, here's the plans I made: