Model of an Installation for Tarring Rope Yarn

Entry

Model of an installation for tarring rope yarn, on a floorboard. Its operation remains unclear. To one side a tar reservoir is suggested, with two holes to lead rope or a number of yarns through. On the other side a frame with a gear train is erected, which looks like a press. Two wheels turn on top of each other: the upper one has a flat surface and turns in the groove of the lower wheel. A set of cheeks, lying on top of and following the curve of the lower wheel, also guide the movement of the upper wheel. The motion of both wheels is synchronised by a set of double cogwheels besides each wheel. The upper wheel and its cogwheels is mounted in a frame that can be lowered and raised on one side with a lever with a weight at the end, to increase or decrease the pressure. The lower wheel is driven by a crank, now missing, and has another cogwheel at the side of the frame, which probably together with a ratchet, now missing, prevented it from turning back.

The identification of the model² was based on elimination and therefore remains uncertain. It was partly reconstructed with loose parts (lever, cheeks on the lower wheel). As far as we could reconstruct, the rope yarn was led through the tar and up between the wheels and cheeks, where it was pressed to get rid of surplus tar.

During his visit to North America in the sloop of war Pallas in 1825, Julius Constantijn Rijk (1787-1854) described a tarring machine that seems to match this model.³

The practice of tarring rope yarn was abandoned by the Dutch Navy in the first half of the nineteenth century: experiments between 1815 and 1827 had asserted that rope tarred after having been allowed to rest for a period of two to three years became much stronger than rope made from tarred yarn, although it was weaker immediately after tarring.