I wanted to finish first the evolution of the belgians destroyers but the idea was too exciting......................
The initial naval program for the new belgium navy was to use small cruisers and torpedo boat to complete their futur battleship. A class of three small cruiser was ordered from France 1886.
They were based on a reduced version of the Forbin which was under construction . As it was intended to operate as training ship and royal yacht the first ship was finally enlarged to a near sistership of its french cousins.
the French builder heard about the project of replace cruiser and torpedo boat with a new design, so they rushed the construction of the cruiser to prevent the belgians from cancel it.
The ship was commissioned in 1890 (earlier than the forbin) as provisory admiral ship.
He fulfilled this role until being replaced by the Baudoin in 1892. Then operated as training ship and royal yacht, mainly in tropical waters.
In 1891, after that his second submarine project was rejected by spanish naval authorities, Isaac Peral retired from active naval duty , founding an electric company in Madrid.
He was then contacted by belgium naval authorities . the Belgian naval attaché had assisted to the 1888 trial of his submarine and made a very enthusiastic report. The belgian admiralty proposed to the former spanish officer to develop a comparable design for them.
With the oportunity to implement its company in the much more industrialised belgium and the waranty that the design would be transfered to spain if the armada show some interest in it , Peral accepted the proposition.
The result of this deal was the Espadon/Zwaardvis class of three sub comissioned in 1894.
They were operated as coast defence squadron in the north sea.
To increase the range of its submarines, the belgian navy decided to convert the l’Union into a dedicated ship. It was intended to operate as a mothership with a semi-diesel generator to increase it capacity to produce electrical power.
For long range convoying, it could carry two submarines, or it could power their electrical motor directly with it's generators through three cable connected to rafts.