Shellfish farmers use rafts at deepwater sites to suspend culture systems used for different stages in the rearing of oysters, clams and mussels. For example, many shellfish farmers suspend tray systems that are used as nurseries for juvenile oysters and clams as well as for oyster growout. This method of “off bottom” farming is considered one of the most productive in the world.
Rafts must be built to withstand the severest weather, hold the weight of hundreds of dozens of mature oysters, and serve as safe work platforms for workers handling product. Important considerations in the design of a raft system include flotation, flexibility, stability, functionality, durability and capacity.
The raft system must be securely anchored to prevent movement and/or drift. Rafts are usually roped together and securely tied at three points on each raft and then anchored at each end. Anchor ropes will sway in the currents and slacken at low tides.