by Kent Lewis
In our shop we have a lot of tools that have come to good use when working on wooden boats. One of the least conspicuous is a pile of small zinc-plated fender washers.
With oversize diameters and small holes, fender washers were developed for working on automobile fenders where the sheet metal would be distorted when pressed by smaller washers. I can’t remember where we came across the idea to use them in working on wooden boats, but I am glad that we did. We often encounter tasks that are beyond the reach of clamps, and a fender washer and a screw can pull parts together, like bending a plank into position on a frame, stem, or transom.
We’ve tried to close gaps between pieces using the wood screws that will be the permanent fastenings, but found that method fraught with problems. The heads of wood screws can bury themselves, damaging the workpiece and then becoming difficult to remove without lifting and splintering the top fibers of wood. And the conical underside of a flat-head screw can act as wedge and split a plank end. The finer threads of silicon-bronze or marine stainless-steel screws may not bite as well into softer wood, and while those screws can be used to hold parts together, they’re not well suited to closing gaps. A screwdriver can also cam out of the slot in a softer bronze screw head, requiring replacement of the damaged screw. To avoid these problems, we use fender washers with drywall or deck screws as temporary fastenings while we drill for and install the permanent fastenings.
Fender washers are especially useful when working with softer hardwoods. We once needed to pull a cypress plank tight to a frame during a repair and first tried using a single silicon-bronze wood screw, but the screw buried itself under the surface, did not have enough bite to pull the plank, and stripped out of the frame. We then tried using several bronze wood screws to distribute the load but ended up shearing some of them, and nothing is more fun than dealing with half a screw in a frame while the plank is not pulled tight. When we switched to a fender washer and a deck screw we fared much better. A deck screw’s star-drive head has an exceptionally secure hold on the driver bit, and the longer, coarser threads of the deck screw bit right into the frames and pulled the plank tight. Once the cypress plank was properly positioned and the permanent fastenings were installed, we removed the deck screw and used that hole for another permanent fastening. In some cases, we’d fill the hole with thickened epoxy or a wooden plug.
We also use fender washers when working with plywood panels. The washers prevent damaging the layers of ply while the panel is being shaped to the molds and fastened. Without the washer, the screw head might crush the multiple thin layers of plywood, either leaving a lot of damage to finish, or even compromising the integrity of the panel. A rough-cut panel can be left on a mold for a few days to help preset a bend, making final installation easier. If the plywood is reluctant to make a bend you can help it along by covering it with towels, pouring boiling water over them, then covering it all with plastic sheeting to hold the heat. Use zinc-plated or stainless-steel washers—plain steel will stain the wood black.
Kent and Audrey Lewis used quite a few fender washers during the restoration of their 1880s Mississippi River Skiff BARBASHELA and their 1950s Alcort Sailfish ZSA ZSA. More information on their continuing adventures can be found on their blog Small Boat Restoration. www.smallboatrestoration.blogspot.com
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