• U-16 Doutor Montenegro
• U-18 Oswaldo Cruz
• U-19 Carlos Chagas

Officially called Infirmary Assistance Ship(Navio de Assistência Hospitalar, in portuguese), these ships were designed specifically to provide medical assistance on rivers with shallow waters. They have a helicopter landing platform and carry two launches that can extend the vessels' reach into even shallower and narrower waters than the parent vessels can access. The vessels have two sickbays with a total of six berths, an operating theater, up to three dental offices, a laboratory, two clinics, and X-ray facilities.

The vessels' main characteristics are:

• Length: 47.18 meters
• Beam: 8.45 meters
• Depth: 2.90 meters; maximum draught -- 1.75 meters
• Full load displacement: 500 tons
• Cruising speed: 9 knots
• Range: 4,000 miles
• Personnel: 4 officers, 6 doctors and a dentist, 15 technical health personnel, and 21 enlisted men.