In 1896, the Brazilian Navy began the construction of three riverine monitors to be used at the Parana-Paraguay River Basin. One of them, P-1 Pernambuco, was ready in 1910 and was used in both world wars. The construction of other two, P-2 Parnaíba, and P-3 Paraguassu, lasted until 1938 when they were incorporated to the Navy. All three were used in World War 2 at Salvador Harbour defence. I used Stugger U-17 Parnaíba as a starting point. All three had the same hull but were modified in the long building process. This is Paraguassu in 1938: