An analysis of vessel loading of export logs at four New Zealand ports.
Degree GrantorUniversity of Canterbury
Degree NameBachelor of Forestry Science
Over half of New Zealand’s annual harvest was exported as logs in 2015 (MPI, 2016). The large scale and economic importance of log exports highlights the importance of efficient port operations.
Productive cycle elements for the log loading operation were defined. The vessel loading cycle was split into six elements: three ‘action elements’ (loading, tallying, and slinging), and three ‘carting elements’ between the ‘action elements’. Time study measurements were carried out at four New Zealand ports (Tauranga, Marsden Point, Gisborne, and Port Chalmers) to identify differences in productive time to load log export vessels. Port Chalmers wasn’t compared to the other ports as it was too different operationally. Loading had the longest productive element time, followed by slinging and tallying, and lastly the ‘carting elements’.
Loading was uninfluenced by port but affected by log grade, length, operator skill, and the time of day. Tallying was significantly different between the three ports with Marsden Point fastest and Tauranga slowest. Slinging was quickest in Gisborne and faster whilst loading below-deck and during the daytime. Carting elements were heavily influenced by distance to or from log stack for all four ports.
Tauranga displayed the fastest historic gross load rate (JASm³/hour) yet the slowest productive cycle time. Gross load rate is influenced by delays, volume per cycle, and productive cycle time. The difference in productive time and gross load rate could therefore be assumed to be from increased volume per cycle and/or reduced delays in Tauranga. Exporters are fined for loading slower than scheduled. This cost is greater when shipping rates are high as fines are based on shipping rates. A 5% increase in loading efficiency can save the exporter US$11,000 per vessel at historic maximum shipping rates.