Found this article tonight and thought about your MOD!
http://www.hisutton.com/Brazilian-Navy-Sip-Ceara.html
The Surprising Secret Of This Brazilian Navy Ship From 1915 ~ 1946
Brazilian Navy's “Ceara” Submarine Tender
BraziliaCearas Specifications
Displacement: 3,500 tons light, 6,400 tons fully loaded
Length: 101.6 m
Beam: 15.7 m
Draught: 6.45 m (fully loaded)
Speed: 12-13 knots
Propulsion: 2 x 2,100 HP Diesel engines, 2 shafts
Armament: Modest weapons. Possibly 2 x 101.6 mm, 2 x 57mm 4 x Hotchkiss 3-pounder 'Armstrong', 2 x 7mm Hotchkiss machine guns. Reports vary
Complement: 89
The ship was designed and built in Italy in 1915 to support 3 'FF' type (Foca Class) submarines. These were also Italian and formed Brazil's first submarine force. Small and relatively fragile, they primarily provided training in Brazil.
FF Type (Foca Class) Submarine Specifications
Displacement: 160 tons surfaced, 260 tons submerged
Length: 46 m
Beam: 4.4 m
Draught: 4.4 m
Speed: 13.5 knots surfaced, 6.5 knots submerged
Propulsion: 2 Fiat 6cyl 700 hp diesel engines driving 2 electric motors, 2 shafts
Endurance: 1600 nm @ 8.5 knots surfaced, 100 nm @ 4 knots submerged
Armament: 2 x 450 torpedo tubes (some sources say 3)
Complement: 20
Operating Depth: 40 m
Ship’s Fate
Ceara’s service life, from 1917 until 1946, seems unremarkable. And although active on the Allied side in WW2, naturally this ship did not see combat. Yet its long service life meant that it far outlived the FF type submarines which it was designed to house. Subsequent Brazilian Navy submarines were larger and would not fit inside the hangar. So it is unclear whether the hangar was still useful (I suspect not). The design was however still noteworthy, a particularly well-equipped strategic asset