Shipping Logs

Shipping logs is a most detailed and complicated subject, few outside immediate involvement in the trade having more than a rudimentary knowledge of all that is entailed in the safe transportation of these valuable cargoes. Causing perhaps most confusion to outsiders are the proliferation of timber measurement systems and the calculations necessary to convert these measurements of available cargo into just what is possible for certain ships to safely transport. As a result, there is a reluctance for shipowners inexperienced in the carriage of timber to fix their vessels on a voyage basis, preferring instead to guarantee only the cubic capacity of their ship and to employ the vessel on a timecharter basis, leaving more experienced charterers to estimate cargo intake. The alternative may be to employ the ship on a voyage basis with a lump-sum freight fixed during the negotiation and thus not depending on the cargo actually loaded. Measurement assessment may be further complicated by the variable moisture content (and thus the density) of the timber to be loaded. Not only does this vary according to the climate in which the tree has grown, but it is also affected by the time of the year the tree is felled, by how long before the log is shipped and, not least, by the method of loading. At certain ports, for example, it is customary to float logs weighing several tons apiece out to a waiting ship anchored off-shore, which then uses its own gear to hoist and stow the soaked and perhaps swollen timber. Naturally, as the logs drain and dry out on passage, the cargo may literally shrink and reduce in weight. Ships employed in such trades would normally be expected to be fitted with cargo-handling gear with a safe working capacity of, say, 10 to 15 tonnes but, where as sometimes occurs, logs are bundled together, the gear capacity required may be somewhat higher, say 25 tonnes SWL (Safe Working Load). Furthermore, as logs dry out, condensation – especially on voyages from tropical to cooler regions – is like to adversely affect ships’ steelwork which may be further damaged by the necessity of hauling heavy timber around confined cargo compartments.