48. The Authority shall not be answerable- (a) for any misfeasance, malfeasance or nonfeasance of any of its officers or other employees or of any persons acting under the authority or direction of any such officer or other employee; or(b) for any damage sustained by any vessel in consequence of any defect in any of the moorings, hawsers or other things within the limits of the Port which may be used by such vessel: Provided that nothing in this section shall protect the Authority from a suit in respect of any negligence or default on its part or of any act done by or under its express order or sanction.