A tug vessel and a plurality of transport modules connected together in a chain, each including a honeycomb core formed of an array of hexagonal cells (preferably formed of reinforced concrete), are disclosed. The modules and, if desired, the tug vessel are adapted to transport liquids, gasses, semi-solids (e.g. grain) and the like in the cells. Universal joint mechanisms connect the tug vessel and the modules together in a manner which allows the tug vessel and modules to move essentially independently with respect to one another. The tug vessel includes a pair of oppositely rotating propellers, located amidships at the rear of sponsons. In addition, gimbled jet exhaust nozzels are used to control the attitude of the tug vessel. Emptying and filling of the hexagonal cells is accomplished via a conduit array which uses a central cell to act as communication chamber for surrounding cells. Cells located along the lateral sides of the overall array are used to house ballast water.