It is a really beautiful model.
The Ictineo II submarine was very advanced for its time. Is open for debate but is was the first or one of the first to have a double hull. Its inventor made extensive calculations of pressure and compression of its hull and performance. The first one (Ictineo I) was propelled by hand. The ictineo II had a chemical AIP system that, as far as I know, was only tested in a lab because of lack of investors/government support.
The inventor (Narcis Monturiol) died forgotten and with no money.
In the Spanish city of Barcelona there are some monuments and a 1:1 model of the Ictineo II
Axel R. Armada