5. Vessels, Net


			Accumulated
	Cost		depreciation		Net book Value
Balance, April 1, 2018	$	1,728,987,980	$	(189,876,147)	$	1,539,111,833
Other additions		131,193		—		131,193
Depreciation		—		(16,099,795)		(16,099,795)
Balance, June 30, 2018	$	1,729,119,173	$	(205,975,942)	$	1,523,143,231

Additions to vessels, net were largely due to capital improvements made to one of our VLGCs during the three months ended June 30, 2018. Our vessels, with a total carrying value of $1,523.1 million and $1,539.1 million as of June 30, 2018 and March 31, 2018, respectively, are first‑priority mortgaged as collateral for our long-term debt (refer to Note 6 below). No impairment loss was recorded for the periods presented.