Underwater Tools And Equipment Practice Test

When you’re sealing a hole with a plug and wedge underwater, you want packing materials that can conform to the surface and stay compressed under pressure. Wrapping the plug and wedge with fabric, rubber sheet, oakum, or sheet lead provides a flexible, compressible layer that fills tiny gaps and irregularities, creating a reliable seal. Fabric serves as a base, rubber sheet acts as a pliable gasket, oakum (tarred fiber) can swell slightly to block leaks, and sheet lead is soft enough to mold into crevices and distribute the load from the wedge. These materials remain workable underwater and adapt to the surface, whereas rigid substances like epoxy or GRP would not seal irregularities once set, and wax or tar alone isn’t as dependable or durable in wet conditions. Canvas with Herculite isn’t a standard combination for this purpose, as it doesn’t provide the same effective, moldable sealing properties.