( Then ( , ( ( freed ( from ( ( gravity 's ) bonds ) ) ) ( , ( he ( ( ( floats buoyantly ) ( until ( ( the plane ) ( ( descends , ) ( ( ( crushing him ) again ) ( with ( 2gs force ) ) ) ) ) ) ) . ) ) ) ) ) )
(ROOT (S (ADVP (RB Then)) (, ,) (S (VP (VBN freed) (PP (IN from) (NP (NP (NN gravity) (POS 's)) (NNS bonds))))) (, ,) (NP (PRP he)) (VP (VBZ floats) (ADVP (RB buoyantly)) (SBAR (IN until) (S (NP (DT the) (NN plane)) (VP (VBZ descends) (, ,) (S (VP (VBG crushing) (NP (PRP him)) (ADVP (RB again)) (PP (IN with) (NP (JJ 2gs) (NN force))))))))) (. .)))
Then, freed from gravity's bonds, he floats buoyantly until the plane descends, crushing him again with 2gs force.
(ROOT (S (SBAR (IN If) (S (NP (DT the) (JJ buoyant) (NN force)) (VP (VBZ is) (ADJP (ADJP (JJR greater)) (PP (IN than) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NN gravity)))))) (S (VP (VBG acting) (PP (IN on) (NP (DT a) (NN ship)))))))) (, ,) (NP (PRP it)) (VP (MD will) (VP (VB float))) (. .)))
If the buoyant force is greater than the force of gravity acting on a ship, it will float.