If you work in the marina industry it is important to understand the difference between freeboard and live load capacity and how the two affect the stability and use of a floating dock.
Freeboard, in simple terms, is the height of a dock’s deck above the water.
Live loads are variable and include all unfixed items on the dock such as people and personal items. Basically live loads are how much weight you want a dock to support without sinking.
The two are related. The more live load placed on the dock the greater affect that extra weight has on how high the dock floats in the water.
This is where the discussion gets more technical. All things float based on the concept that they displace the water they are floating on. Salt water weighs approximately 64 pounds per cubic foot. So if we divide 64 by 12 we get 5.33 pounds, which means, if we’re using round numbers, if 5 pounds of pressure is applied to the top of an object, measuring one square foot, floating in salt water, the object will sink 1 inch.
With that simple concept in mind, we can show how live load capacity affects the freeboard of the two most common types of floating dock systems. Continue Reading…