Better Oyster Shaping With the Solar-Powered Tumbling Agitator

Tumbling is important for sorting and shaping oysters. However, tumblers can sometimes fall short of shaping oysters as much as growers would like. This simple and effective fix helps increase the shaping power of any tumbler.

Author(s): Charlie Neill, GMRI Intern
Source: Deer Isle Oyster Company
Date: 2024

Cultivating Nicely Shaped Oysters

Tumbling is a crucial part of most oyster farming operations because oysters regularly need to be sorted into different size categories and encouraged to grow into an aesthetic shape. Tumblers are excellent at sorting oysters, but sometimes they fall short of chipping off new growth to develop the deep cup that is desired. This simple modification that can be made to any tumbler helps improve its chipping ability and leads to a better product.

The Tumbling Agitator

At Deer Isle Oyster Company, they added a small piece of line running through the tumbling tube to increase its ability to shape oysters. The rope creates an extra disturbance that jostles the oysters as they make their way through the tube, a 'trip line' if you will. Inspired by the fins on the drum of a clothes dryer, the rope creates a bump that tumbles the oysters more than the flat inner surface of the tube would. This solution is cheap, easy to install, and works quite well at what it’s designed for.

Note the rope running the length of the tumbler. In this case Deer Isle Oyster Co. uses two sections of rope for the first half of the tube and one section for the latter half.

How To Make Your Own Tumbling Agitator

The tumbling agitator is made from two sections of rope attached to the tumbler drum. More ropes or larger ropes cause more agitation, and a smaller rope causes less agitation.

Cut a section of rope about the same length as the tumbling tube.
Feed the rope through the hole closest to the top of the tube, and tie a stopper knot on the outside of the tube.
Run the line through the inside of the tube, then feed it through a hole on the bottom end and tie a stopper knot.
Using twine, secure the larger rope in place in the middle of the tube, and in more places along its length if desired.

The perspective of an oyster about to enter the tumbling tube at Deer Isle Oyster Company!

Some More About the Deer Isle Oyster Co. Tumbler

The tumbler at Deer Isle Oyster Co. is homemade and runs completely off solar power. Making a DIY tumbler was the best option for the crew, but they didn’t want to sacrifice performance or energy sustainability with the easiest route forwards. The small solar array on the roof of their float charges a single lithium-ion battery that is enough to fulfil their energy needs for the tumbler motor and a small washdown pump.

The solar panels, charge controller, and lithium-ion battery on the Deer Isle Oyster Co. float.

In addition to the agitator line and solar array, Deer Isle Oyster Company also uses two rubber mats to cover their tumbler during operation. The mats keep spray from soaking the operators and dampens the sound of tumbling oysters. This makes the whole tumbling process more pleasant for the farmers and local neighbors.

The rubber mats hang over one side of the tumbling tube protect employees from splashes and help dampen noise.

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