The simple theory of dock floating is that more width, length, and weight added to a floating dock, the more stable it becomes. For example, 4' x 10' dock fingers are not as stable as a 10'x10' dock section.
The Term Freeboard for Boat Docks
The term freeboard means height deck above the waterline. most residential designers aim 12" to 24" of freeboard. Dock floats with 12" and 16" height will be within the average freeboard range. If your prime use of the dock is to moor a boat, then a dock freeboard height needs to be adequate for loading and unloading a boat. An added benefit for a lower freeboard is that it will increase the stability of the dock.
Calculating buoyancy for Docks
The basic general rules for calculating buoyancy for a residence floating dock is 30lbs per square foot and 40lbs per square foot for commercial docks.
Length x Width = Square feet of dock
Square feet x 30 lbs (10lbs Materials & 20 People weight) = Total buoyancy
Divide total Load by dock float model number
Example: 10' x 14' dock = 140 sq. feet
140 sq. feet x 30 lbs. = 4200 lbs.
4200 lbs./ 525 lb buoyancy dock float = 8 floats