THE RIGHT STUFF

Paying it Out Steve Zimmerman

As a teenager, I worked summers on a lovely wooden sailboat named Rosa II. She had a traditional teak deck of solid, 1 1/ 8inch thick planks, with cotton pounded into the seams and thick black caulking payed over the cotton into the seam to keep out water. Every spring began with the painful process of chasing leaks until the decks finally swelled tight. On sailing ships, the crew payed the seams with hot pitch. They called the seam closest to the outboard edge, where one might most easily fall overboard while paying, the devil seam. That led to a popular play on words among sailors: “You’ll have the devil to pay and no hot pitch.”

Modern teak decks keep out the water far more effectively. Nonetheless, seams still must be payed. This photo shows the actual shape of the caulking seams— a notch, or rabbet, cut into one edge of each plank. The seam compound eventually dries and cracks and loses adhesion to the wood, allowing water in. Once that happens, it all has to be removed and the wood sanded and cleaned. Next comes the tricky part. The wood will expand and contract with changes in temperature and humidity, challenging the ability of the seam compound to maintain its adhesion. If held on three sides, the seam compound will likely come loose. The small strip of tape hanging out the end forms a bond break, preventing the compound from binding to the bottom of the seam. By allowing adhesion only to the two sides, the seam compound will move freely with the wood and will maintain its bond for many years. A small detail to be sure, but a great example of the Right Stuff. n