Hello! Since I am an M. Tech in Solar Energy (Gold Medalist) with over 2 years of experience in this field, I believe I am the right candidate for this task. We have done solar off-grid (with battery), hybrid as well as grid-tied solar projects.
This falls under the off-grid category, and can be solved. Diesel ferry can run on solar, and diesel can be used as a backup.
Let me know the exact details and I will design the system.