Syphering is an older boatbuilding and carpentry technique where the edges of planks are beveled and then overlapped. Unlike a standard lap joint that leaves a stepped profile, syphered edges mate along their chamfers to form a completely flush face. This method is often used in bulkheads or watertight partitions where a smooth surface is required.
Heard on the job
We'll sypher the bulkhead planks to keep the interior wall perfectly flat.