Entire Document - California Department of Boating and Waterways ...

Pontoons made exclusively with polystyrene or polyurethane foam, withoutprotective shells, are subject to the dissolving effects of hydrocarbons such asgasoline and oil. Obviously, such exposed foam pontoons should never be usednear fuel docks. Also, exposed foam is subject to mechanical wear from debris inthe water, and damage from gnawing animals such as muskrats and other saltseeking rodents. The foam inside pontoon shells is the only insurance against amarina sinking. The foam must be protected.C6.6 Where polyethylene pontoons are used, it is recommended that thefollowing guidelines be used in the specifications:P Method: Roto-CastP Material: Linear Low PolyethyleneP Nominal Wall Thickness: 0.150 inchesP Color: BlackCC6.7 Where concrete pontoonsare used, the walls, bottom andtop act as a closed pontoon shelland a structural frame. They arevery rigid, heavy, and provideexcellent docks in relatively quietmarina basins. They probablyshould not be considered formarinas in open water locationssubject to wave heights over 12-14 inches unless designed andbuilt to also act as a waveattenuator.C6.8 The loadingcharacteristics of a pontoon aredictated by the vertical crosssection. Both rectangular andcircular pontoons are used forflotation.C6.8.1 Rectangular pontoonswith essentially vertical sidewalls, load in a linear straightlinefashion. As eachincrement of applied loadsinks a pontoon deeper intothe water, the pontoonresponds with a proportionallyincreasing pontoon buoyantuplift.Rectangular Pontoon Loading CurveBased on a 1 ft 3 Pontoon, 12"x12" by 12" LongCircular Pontoon Loading CurveBased on a 1 ft 3 Pontoon,13.54" Diameter by 12" LongCSECTION C Berthing - Page 30