(S (S (NP (BASENP (PRPD His) (NN boat)) (PRN (COMMA ,) (BASENP (DT the) (NNP Zeeman) (NNP Challenger)) (COMMA ,))) (VP (VBZ is) (BASENP (DT a) (JJ seven-metre) (JJ custom) (NN plywood) (NN vessel)))) (PERIOD .))