A review of the prior and amended contract would be required to give any meaningful analysis. Having damages without a breach of a contractual obligation is not "always" recoverable.
The above is general legal and business analysis. It is not "legal advice" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.
You made have a case, but it is impossible to tell without reviewing the contract. You need to speak to a local attorney so that he can review the contract as well as the changes that you described and advise you regarding your situation.
I understand that you have a contract, presumably in writing, with a company that leases the dock from which you operate a charter boat. The first step is to determine whether the company violated your contract. For example, does the contract say whether the company is allowed to make changes? If they are allowed to make changes, does it say whether they must notify you first - in writing or otherwise? If the contract is unclear, consult with a lawyer to help you interpret. IF you believe that the company DID violate the contract then that = a breach and if you were damaged because of the breach then your contract may indicate what you are entitled to recover. Again, if its unclear - speak with a lawyer.