Foam pack The foam filling this pack aids buoyancy and is so dense that it cannot be made any denser by the enormous pressure at 10,000 feet. It might be foam, but it ain't light: when in "liveboat" mode, ROPOS tips the scales at 3,600 pounds, while in deep mode (shown here), which features nothing more than a fatter foam pack, it weighs in at a full 6,000 pounds. back to NOVA's Into the Abyss Home ©