( ( If ( you ( release ( enough gas ) ) ) ) ( you ( ( generate ( ( a foam ) ( ( having ( such ( low density ) ) ) ( that ( ( a ship ) ( ( would not ) ( be ( able ( to ( displace ( enough ( to float ) ) ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (SBAR (IN If) (S (NP (PRP you)) (VP (VBP release) (NP (JJ enough) (NN gas))))) (NP (PRP you)) (VP (VBP generate) (NP (NP (DT a) (NN foam)) (VP (VBG having) (NP (JJ such) (JJ low) (NN density)) (SBAR (IN that) (S (NP (DT a) (NN ship)) (VP (MD would) (RB not) (VP (VB be) (ADJP (JJ able) (S (VP (TO to) (VP (VB displace) (ADJP (JJ enough) (S (VP (TO to) (VP (VB float)))))))))))))))) (. .)))
If you release enough gas you generate a foam having such low density that a ship would not be able to displace enough to float.
(ROOT (S (NP (NNS Gases)) (VP (VBP have) (NP (DT the) (JJS lowest) (NN density))) (. .)))