The riverbed of the Kupa, next to the village of Kamensko, east of Karlovac in Croatia, holds the remains of a sunken Roman-era river barge well preserved under the cargo of bricks it was transporting. Discovered in 2009 and briefly excavated from 2011 to 2013 by the Croatian conservation institute, the shipwreck has been systematic researched since 2015 by a team from the Croatian conservation institute and the Centre Camille Jullian, making Kamensko the first river shipwreck in Croatia to be systematically excavated underwater. This river barge, wide 2 meters and preserved in the length of 12 meters, is a flat-bottomed vessel of a bottom-based construction dated by AMS radiocarbon dating between the 1st and the 3nd centuries AD (85-234 AD). On its last journey the barge was transporting a cargo of several hundred lateres sesquipedalis, most of which were found in situ within the barge’s hull. A large number of the bricks bear an identical workshop mark (a letter alpha), testifying to the homogeneity of the cargo hailing from a regional production centre that exploited the local waterway network.The Kamensko barge shows a number of unique architectural characteristics such us the large carved-out bilge strakes from oak timbers and the waterproofing of the hull achieved by the use of a kind of vegetal fibres maintained by numerous small, tightly-spaced, metal clamps. These clamps possibly play also a function of junction between the strakes. The use of clamps approach this vessel to some other Roman river vessels discovered in Slovenia (Sinja Gorica and Vrhinika), in Croatia (Sisak) and in Serbia (Kušjak) permitting, as proposed by G. Boetto, the identification of a regional inland shipbuilding tradition of the Danube basin. This tradition has to be distinguished from a second regional inland shipbuilding tradition characterised by the use of the sewing technique borrowed from the Adriatic maritime shipbuilding traditions whose the Slovenian barge from Lipe is the most known example.