In place of the oakum and pitch normally used to caulk ships, lead was used. It is fashioned from peeled logs, with the gaps filled with moss, oakum, and chinking. Originally rope or oakum packing was used. Hard labour included rock breaking and oakum picking. Found in the cracks of the floorboards were needles, pins, thimbles, oakum, string and buttons. Logs for the cabin are peeled Engelmann spruce with full dovetail notch and oakum chinking. Female prisoners picked oakum, knitted stockings or sewed. There were oftentimes 2-3 layers of this oakum fiber placed in between the planks. One of the workers accidentally ignited a ball of black oakum with a light. Thread seal tape, oakum, or PTFE string, or by using a mechanical coupling. In modern times, the fibrous material used in oakum comes from virgin hemp or jute. These included breaking stones, operating a water pump, and oakum picking. Tar-like petroleum by-products can also be used for modern oakum. Boats carried oakum and chisels to patch leaks. They would have unpicked oakum for up to 10 hours a day.