The Commissioners of Bridlington Harbour may, for the Purpose of maintaining and improving the Harbour, with the Consent of Her Majesty in Council, impose Rates on Vessels using the Harbour, and on Goods shipped or unshipped in the Harbour, not exceeding the Rates specified in Schedule (A.) annexed to "The Burgh Harbours (Scotland) Act, 1853," and may from Time to Time, with the like Consent, vary such Rates by reducing or raising the same, so that they do not exceed the Rates mentioned in the said Schedule; and any Rates so imposed may be either in lieu of or in addition to any other Rates leviable by the said Commissioners.