HDS-500 is also known as HDS-500RTN (Royal Thai Navy) and KSS-500A
HDS-400 is a related design (TBC) that has actually been laid down for an undisclosed customer
Key:
a) Flexible Payoad Module (FPM)
b) Integrated sail
c) Intercept sonar
d) Hatches for Payload Modules
e) 533mm (21") torpedo tube (x2)
f) Conformal sonar array
g) 324mm (12.75") torpedo tubes (x4)
From http://www.hisutton.com/News%20-%20Korea%20building%20new%20HDS-400%20midget%20submarine.html
HDS-400 is a related design (TBC) that has actually been laid down for an undisclosed customer
Key:
a) Flexible Payoad Module (FPM)
b) Integrated sail
c) Intercept sonar
d) Hatches for Payload Modules
e) 533mm (21") torpedo tube (x2)
f) Conformal sonar array
g) 324mm (12.75") torpedo tubes (x4)
From http://www.hisutton.com/News%20-%20Korea%20building%20new%20HDS-400%20midget%20submarine.html