The Type 2400 features a single skin hull clad in elastomeric acoustic tiles, a 5-man Diver Lock-out in the fin, and a passage on 2 Deck enabling crew to pass from forward to aft without going through the Control Room.
Upholder's propulsion system comprised two high-speed diesel engines - Paxman Valenta 1600 RPA-200S -marinised versions. of those employed in the latest diesel railway locomotives of that era. Each of these was coupled to a 1.4MW generator and a double-armature main motor that drove the single propeller. The generators could be used either to provide power to the main motor directly or to charge the boat's main batteries.
