The Company's vessel operations are organized into two segments: Crude Tankers and Product Carriers. Our 48-vessel fleet consists of VLCC, Suezmax, Aframax, and Panamax crude tankers, as well as LR1, LR2 and MR product carriers. Through joint venture partnerships, our fleet also includes ownership interests in four LNG carriers and two FSO service vessels (together the “JV Vessels”).
INSW generally charters its vessels to customers either for specific voyages at spot rates through the services of pools in which the Company participates, or for specific periods of time at fixed daily amounts through time charters or bareboat charters. Spot market rates are highly volatile, while time charter and bareboat charter rates provide more predictable streams of TCE revenues because they are fixed for specific periods of time. For a more detailed discussion on factors influencing spot and time charter markets, see “— Fleet Operations — Commercial Management” below.
With a focus on strengthening the Company's fleet profile and earnings power ahead of an anticipated market recovery, the Company has opportunistically disposed of some of its older vessel tonnage and invested over $600 million in modern vessels at historically low asset prices since its November 2016 spin-off from its former parent company. These investments included the acquisition of two Suezmax newbuilding resales and a 2010-built VLCC during the second half of 2017 and the acquisition of six 300,000 DWT VLCCs consisting of five 2016-built and one 2015-built (collectively, the "Six VLCCs") during 2018. The Company also disposed of 13 owned vessels with an average age of 16.3 years during 2017 and 2018. As of December 31, 2018, the Company's fleet renewal program has reduced the average age of the Company's owned and operated fleet by approximately three years from 11.5 years at the end of 2016 to 8.7 years at the end of 2018 while increasing the deadweight tonnage of the Company's fleet by approximately 11.5%.