Submarine minelayer offered by Dutch shipyard Kon.Mij. De Schelde at Vlissingen, Netherlands to Portuguese navy in 1931

Brazilian design 

On 6 July 1931 sent a tender to commander Ralph J. Hanson at London, United Kingdom for building a submarine minelayer for the Portuguese navy. Costs without torpedoes, periscopes, compasses, wireless etc. for ƒ 170.000 pond sterling.

The De Schelde designed in 2934 also a submarine minelayer for Brazil which would have been more or less similar to the Portuguese tender.  

Source

Archive Scheepswerf Kon. Mij. De Schelde 1875-1970 inventory no. 1224 (Municipalty Archive Vlissingen, Netherlands archive no. 214).