Rio de Janeiro Maru
Former luxury liner (9,626 t) converted to a transport, sunk on 16 Feb 1944 by Essex aircraft (bombs); she lies on her starboard side so the port side is heavily encrusted with coral. The huge twin four-bladed propellers, the largest bow and stern guns in Truk (the aft gun is about 5 m long), the twin 7,500-hp engine room and holds with artillery, china, bottles and sake can be explored.
Facts
- Region: Chuuk (Truk) Lagoon – Micronesia
- Area: Uman & southern lagoon
- Depth: 9–34 m
- Level: intermediate
- Current: low
- Type: wreck
- Coordinates: 7.304216, 151.90085
- Highlights: bow gun, stern gun, engine room, propellers, sake bottles, china
- Permit: A Chuuk State dive permit is required for every dive on the wartime wrecks (Chuuk Lagoon State Monument): US$50, valid one year, as listed by Odyssey Adventures, SS Thorfinn and the Blue Lagoon Dive Shop rate sheet (the older state-code text says US$30, so confirm when booking). Under the state code the permit is sold by the licensed dive shops/operators, who collect the fee for the state, and divers must go with a certified guide from a licensed shop. All Japanese ships and aircraft sunk before 31 Dec 1945 are protected monuments and war graves: taking or damaging anything is illegal (fine up to US$1,000 and/or six months in prison under the state code).
- Issuer / contact: Chuuk Visitors Bureau (CVB)
- Phone: +691 330-4133
- Email: executivedirector@visitchuuk.com
- Website: https://visitchuuk.com/contact-information
- CVB is the Chuuk State tourism office and is listed here as the official contact for visitor information; the permit itself is sold by the licensed dive operators (Chuuk State code Title 25 ch. 8, text at https://faolex.fao.org/docs/pdf/mic79052.pdf). Operators (Thorfinn, Odyssey, Blue Lagoon) list US$50.
- Unverified: Operator map places her about 2 km east of Uman; other guides say '400 m east of Uman Island', and depth figures differ between sources (about 30–40 m).
- Tips: Gentle intermediate wreck; the engine room takes about 30 minutes to explore with a guide. Wrecks are war graves – look, photograph, take nothing. Some cargo (shells, mines, bombs) is unstable: do not touch it.