Looks a bit like a shark, but the shark is a two hulls boat ( project 941 ) meant installing ICBMs on submarines to reduce the rocking of the boat in the launch of a missile, in fuselage were 2 separate hulls case this increased the survivability of the boat ( you can movement between all compartments if damage to one ), the constructive strength ( and hence the depth of immersion ), and also allowed to launch missiles underwater including under 2 meter ice

In FTD the boats must be build of rubber because sonar can not see this block, all sensors connect via connection, without receivers ( Wirless Snoper it did not notice ) all that might radiate heat, such as exhaust pipe, hiding under the boat because IR cameras can see through water ( this applies to screws if they hidden rubber block passive sonar not see their), and not worth to put any active device only passive. Then the boat will be invisible ships visible. But if not enabled detected without sensors ( in game optional ).