Back to: Gear Selection
Many farmers find selecting the appropriate anchors to be one of the most difficult components of the farm design process, because there’s no one-size-fits-all solution. Depending on which array type you intend to build and your site conditions, your anchors could vary dramatically in size, shape, and cost.
When your gear is in the water, it will have to withstand a variety of forces from the marine environment. Your farm’s exposure to prevailing wind and weather, the current velocity, the tide, and the weight per foot of kelp on your growlines will all contribute to the cumulative drag force placed on your gear. To counteract this, your anchors should have enough holding power to withstand the drag force and secure your gear in place. Holding power is also sometimes called breakout force; it is commonly measured in pounds.
The combined forces placed on your array by the marine environment that attempt to move or dislodge your anchors; more broadly, a mechanical force generated by the interaction and contact of a solid body with a fluid.
The pounds of force that an anchor can hold per pound of anchor dry weight; also called breakout force.
Determining the exact holding power requirements of your farm design requires a bit of complicated trigonometry, but it can be calculated, roughly, with the equation below.
You can find a more detailed breakdown of this calculation, as well as information on the scientific paper from which it’s derived, here:
In the Farm Design Tool, we’ve calculated these forces for you, based on the parameters you entered about your farm, with a built-in safety factor.