Nov 28

Unadilla-Class Gunboats

Wednesday, November 28, 2018 11:59 AM

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Did you know that today, on the 28th of November, 1863, the USS Chippewa convoyed the Army transports Monohansett and Mayflower up Skull Creek, South Carolina, on a reconnaissance mission? I don’t imagine the majority of folks do, unless they are American Civil War buffs, but I learned that particular fact perusing through today’s events in history, looking for a subject for my blog post. While the specifics of this mission (which was successful, by the by) aren’t the subject of my blog post today, looking into this event was the catalyst for what I will be covering: Unadilla-class gunboats.

It wasn’t until coming to the U.S. Naval Institute that I began to fully comprehend and respect the variety of boats and vessels the U.S. Navy has had at its disposal over its 200-plus year existence. The most interesting aspect of this to me was how much the classification of naval vessels resembled a phylogenetic tree a scientist would create to classify specific flora and fauna. Gunboats, for example, can be broken down into a plethora of different classes, some of which are modified versions of older classes, while others did not “evolve” into a new class of vessel.

Just because a class of ship did not evolve does not make it any less fascinating. In fact, many of the most interesting kinds of ships commissioned by the Navy are those that only existed for a short period of time. They are the experiments and the vessels of necessity, and those often come with the best stories.

The Unadilla-class gunboat would be considered a vessel of necessity rather than experimentation. When the Civil War began in 1861, the Union Navy had a distinct lack of ships that could operate in both deep sea and close inshore waters. Without light-draft vessels, the Union could not hope to enforce a blockade of Confederate ports. As luck would have it, however, the Navy’s Chief Engineer, Benjamin F. Isherwood, had only recently designed a similar vessel for the Imperial Russian Navy. He only had to hand the ready-made designs to Secretary of the Navy Gideon Welles, and production of the Unadilla-class gunboats began.

So what makes the Unadilla-class different from other gunboats? First and foremost was the incredibly rapid pace in which the vessels were produced. The first four of the twenty-three gunboats were completed in about three months. The USS Unadilla, which gave the class its name, was commissioned 30 September 1861, only 93 days after her keel was laid down at the shipyard. This amazing feat of speed gave the entire class its nickname, the “90-day gunboats.”

Lithograph of the USS Unadilla (1861) underway.

Lithograph of the USS Unadilla (1861) underway.

While the Unadilla-class was created to enforce blockades, the gunboats participated in a variety of missions, like the USS Chippewa’s mission described at the beginning of this post. Unadilla-class boats participated in the Battle of Port Royal, the Capture of New Orleans, and the Vicksburg Campaign. To my surprise, nearly all of the 90-day gunboats made it through the Civil War intact, and were still extant more than a decade after the war’s completion, though as merchant vessels rather than Navy ships.

This made me wonder: why, if the Unadilla-class was successful during the war, would the Navy allow the class to essentially go extinct? After doing some more digging, the main reasons I saw for the Unadilla-class’s undoing was the design of the vessel. The hulls of the 90-day gunboats were mainly made of wood, with iron braces only used to support and strengthen the wooden structure. Unfortunately, the success of modern artillery pieces against wooden hulls proved that iron and steel was the way of the future, and to keep outdated equipment would weaken the overall strength of the Navy.

If the wooden hull was the Achilles’ heel of the Unadilla-class, the weight of its machinery was the death knell. As with most Isherwood-designed vessels, the engines of these gunboats were more than two times the necessary weight. This hindered the gunboats’ performance immensely, especially in regards to the main purpose of their creation: to act as a blockade. While most blockade runners could reach speeds of up to 14 knots, the Unadilla-class was lucky if they could get up to 10 knots, making it near impossible for the Union ships to catch their targets.

After all of this research, I think what I take away from this exploration is that while necessity is the mother of invention, her children do not always prove to be as successful in the long term as one would hope. But looking at the flaws of past designs should not cause disappointment. Rather, seeing why something did not work provides context for why our inventions moved in a different direction, and can help us create better designs for the future.