Here’s a little silent film of a Landing Craft, Infantry at Noumea being converted to an LCI(G) gunboat to provide close in fire support for other landing craft.
One of the interesting things is the part where you see the arc welder. Arc welding was still a relatively new technology, and only just coming into widespread use in shipbuilding. Think about it. There’s a reason we remember Rosie the Riveter, and not Wendy the Welder. In fact, the first all welded hull wasn’t built until the 1920s. World War II actually had a large influence on the adoption of welding for shipbuilding as it was faster, and easier to train shipyard workers for welding than for riveting work.
The success of the field modified LCI(G) gunboats would lead to the production of 130 of the purpose built LCS(L) Landing Craft Support (Large) ships.