Caulking the Deck

One of the best things we can do to keep everyone comfortable on board the J. & E. Riggin is keep things dry. Especially in the cabins. The best way to keep the cabins dry, is to make sure there is plenty of material in between the pine planks that form the deck. The gaps between the planks are called seams and they are packed tightly with cotton and oakum before being sealed with a layer of hot pitch. As the boat sails, it bows and flexes in the water, causing some seams to loosen up over time and begin to leak. In the winter, we do our best to identify problem spots and remove wet material between the planks before replacing it, and sealing it with fresh pitch. This process is called caulking. Captain Schaefer spends a lot of time each winter crawling across the deck fixing seams, so we joined him on deck for a demonstration.

Capt. Schaefer makes his way down to the boat with a milk crate containing caulking cotton, oakum, an assortment of caulking & reefing irons of different thicknesses and lengths, and a caulking mallet. The cotton is just very loosely spun fluffy bales of cotton. Oakum is loosely twisted hemp or jute fiber wet with pine tar. The irons are meant to drive the fibers into the v-shaped gaps between planks when struck by the caulking mallet. A caulking mallet is a wooden mallet designed to minimize damage to the irons and to the joints of the user by absorbing the shock of each impact.

Capt. Schaefer begins by poking the seams with the tip of his knife. If the knife fails to penetrate the seam he knows it is still densely packed. If the tip of the knife sinks right in, he knows he has identified a problem spot. He then uses a reefing iron and a rubber mallet to dig into the seam and extract the rotten fiber. Once all of the rotten fiber has been removed, it is time to start filling it again.

Capt. Schaefer chooses the right iron for the seam by inspecting the size of the seam and where it is located. “When I am driving cotton I use a thinner iron to start” he says. He lines up a long strand of cotton and systematically pounds it into the seam, driving it in in small arches that overlap slightly. He will then go back after this initial pass and drive the cotton deeper into the seam.

Once the cotton is in place, he makes a pass with a layer of oakum. “If I am driving oakum, I will use a wider iron which matches the width of the seam I am working on. I even have irons that are slightly bent for those seams that are against the side of a cabin house.” In the same way he drove the cotton, he drives a thick layer of oakum on top so there is only about a quarter of an inch of space from the oakum to the top of the plank.

Now that the seam is packed with fresh fiber, he is ready to add the pitch