Find the niche that the other dredge companies don't want to service. Many small projects around that not worthy of bigger equipment overhead operations. Insurance and bonding costs matter. Marina, private slips and shipyards frequently need maintenance dredging. Excavators are accurate up against bulkheads and structures. A good estimator can make or break you until you have the experience. Start small. The good news is that theres a lot of equipment available for stupid short money now, especially on the Gulf coast. The bad news is , theres a reason for that equipment being available... Start small!
Dredging is a natural offshoot of your existing dockbuilding business. Good luck.