Excavated by M. Izaguirre in 1991. The wreck corresponds to a 16th century wooden boat to sixteenth-century wooden boats destined in their time to transport iron ore for the ironworks in the area.

This vessel conserves its structure of upper works from the keel to something less than the waterline. Its characteristics are similar to those of Orio I and Orio II:

•  Frames consisting of floors and part of the futtocks. Their squares vary between 10 x 10 cm and 20 x 20 cm. Their lengths between 1 and 3 m.
•  The keel is the longest piece of the boat and varies between 7 and 9 m in length and 20 x 20 cm squad. The keelson is a straight piece between 2 and 3 m in length and 25 x 25 cm in section.
•  The ceiling planking composed of 3-4 cm boards thick, width between 20 and 30 cm and length between 1 and 7 m in length.
•  Planking composed of planks with an average-thickness betwen 3 and 4 cm, width 30-30 cm and length from 3 to 8 m.

• Izaguirre, Manuel (200).
  Orio IV : La investigación arqueológica de un patache venaquero del siglo XVI.
  Underwater Cultural Heritage at Risk: Mananging Natural and Human Impacts, 73-75. nternational Council on Monuments and Sites. Paris.