SS Eugene V. R. Thayer (Petroleiro do Acaraú)

The SS Eugene V. R. Thayer was an American steam tanker carrying fuel oil from Buenos Aires to Caripito, Venezuela, when it was chased and attacked by the Italian submarine Pietro Calvi on April 9, 1942, in an attack that killed 11 crew members. Fishermen knew it only as Petroleiro do Acaraú, a name taken from Acaraú, the main port of the region. It was identified in 2012, when divers found the letters "AYER" in raised relief on the starboard bow. Porcelain shards inscribed "Iroquois – USA – China", collected from the wreck by a spearfisherman, are an indication that the ship was American.

In 2012 the hull sat upright, in sailing position, on a sandbank, and the stern, separated, listed to port with the large engine exposed. In 2023 the ship was partly intact, with the bow and stern better preserved and heavy destruction amidships, and on the stern one could see winches, mooring bollards, part of the shaft, the rudder tiller and the toppled funnel. In 2016 the hull had the first documented record of the invasive coral Tubastraea tagusensis in the northern region of Brazilian coral reefs, at densities of 16 to 872 colonies per m². A 2019 genetic study found this sun coral population to be the most divergent among the invaded sites in Brazil, most likely the result of a single introduction.

In 2012 there were many barracudas and large schools of fish, as well as a cobia, a stingray in one of the holds and a group of spotted eagle rays. In 2023 a stingray, a school of barracudas and surgeonfish were seen on the wreck, along with a few lionfish, which are invasive. Also in 2023, two species of sun coral, likewise invasive, dominated the hull. The best time to visit the wreck tends to be from March to May, since for most of the year the sea does not allow the trip. In Ceará, generally, the best diving season tends to be from March to July, even though it is the rainy season.