This is the file set that I used to convert a stock Thundertiger Neptune to a DSRV Alvin look-alike. Parts are designed to mate to the stock body using high-strength adhesive, but still allow access to remove the body shell for maintenance or repair. 

Parts included: 
Six individual parts for the manipulator arm
Four hull sections
Floodlight with surround
Upsized dive planes
lifting lugs
Two Sail parts
Operator's seat
Vertical thrusters