Caulking - San Francisco Maritime NHP Volunteers in Parks (VIPs)

San Francisco Maritime National Historical Park


Caulking Transcript

Slide Narrative 1 Hi, my name is Steve Johnson and I’m a docent at the San Francisco Maritime National Historic Park. I’m here to talk about ship caulking: what it is, why it is important to San Francisco maritime e history, and how to do it. I’ll include a demonstration of deck caulking. 2 Ship caulking is sealing the seams of hulls and decks on wooden ships. It’s done to keep water from penetrating into the interior of the ship. The caulking trade dates back at least 400 years. The SF Bay had hundreds of wooden ships around the turn of the century and it was important to have ship caulkers trained to maintain the integrity of the hulls of those ships. 3 This slide shows what the San Francisco Bay looked like in 1915 -- (the year of the San Francisco Exposition.) You can see the Ferry Building and Hyde Street Pier. Notice the large number of wooden ships in the bay. And that there are no bridges across the bay. The Golden Gate and San Francisco Bridges weren’t completed until 1937. The main method of crossing the bay at this time was by ferryboat. There were about 26 ferry routes across the bay. Most of these ferries were made of wood. The ferries carried people and automobiles; separate ferries carried railroad cars 4 This is what the Hyde Street Pier looked like in 1931. The pier was one of several ferry terminals in San Francisco, the primary one was at the Ferry Building. The Hyde St. Pier had 5 ferry routes, primarily going to Sausalito and Berkeley. 5 My grandfather was a ship caulker. His name was Fred Burnett. He was born in 1893 and was orphaned two years later. He was at an orphanage in Marin County until 1906. He ran away from the orphanage a few months after the Great Earthquake. He and his brother Norman worked several jobs until becoming apprentice ship caulkers, working for the Southern Pacific Railroad caulking ferryboats. Over his career Fred worked around the Bay Area, plus up and down the west coast of the US. He also spent a year at Pearl Harbor prior to the attack. 6 Fred was an apprentice caulker in 1912 when he met his future wife, Mary. It was love at first sight. They “kept company” (as dating was called in those days) for three years until he completed his apprenticeship and they could afford to get married. They were married on December 31, 1915. They were married for 57 years until Mary’s death in 1973. This photo of them was taken in 1914, a year before they were married. You can see how happy they were at that time in their lives! 7 This slide shows Fred and his brother Norman at work caulking a ship’s hull. You can see the ship is in dry dock and they are working on a scaffold. You can also the caulking mallets and “oakum” rope hanging down as they work. 8 How do you caulk a ship: First you remove the old caulking with a reef or reaming iron. Then you roll the oakum into a small rope about 12” long. Tap the rope into the seam using a thread (thin) iron. After a couple of threads, make the joint tight using a Making (thick) iron. If you’re sealing a deck, you “pitch the deck” as a final step using heated pine pitch. Modern pitch is actually called marine glue – like roofing tar with a plasticizer. You might use a “hot rod” (like a tire iron), heated in the fire to even out the pitch and remove any bubbles. Finally, you scrape away the excess pitch with a putty knife. 9 These photos show a variety of the tools of the trade used in caulking. The flat ions are used for caulking. The slanted and curved irons are used to remove old caulking; these are generally called “reaming” or reef irons. The caulking mallet is about 12” long with a 12” handle. The rings on the mallet are tempered steel. There is also a photo of a pitch runner. Hot pitch is ladled into the runner, which is then dragged along the deck seam. The pitch runner is shown on a mock-up of a deck. 10 This drawing shows how the oakum is twisted and driven into a hull or deck seam using thread and making irons. 11 Watch this demo video of the caulking process. 12 Here is a photo of Fred doing a caulking demonstration at the Oakland Museum in the mid-1970’s. His motto was “I only do good work!” Not all shipyards and caulkers did the best job possible. In some cases that resulted in the ship needing to be re-caulked sooner. Fred was not one of those “okay” caulkers. He only did GOOD work. 13 Here is a summary of what we talked about today: • Ship Caulking is sealing the seams on wooden ships using Oakum and pine tar. • Caulking was historically important to the San Francisco Bay because of the large number of wooden ships and lack of bridges for crossing the bay. • My grandfather, Fred Burnett and his fellow caulkers made an important contribution to ship building in the early 20th century. • It is important to do ship caulking or any maritime trade craft to the highest quality standards: Only do Good Work! • Thank you for watching this presentation.


San Francisco Maritime National Historic Park Volunteers in Parks Docent Steve Johnson presents ship caulking: what it is, why it is important to San Francisco maritime history, and how to do it.


9 minutes, 16 seconds


Steve Johnson/NPS

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