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Safety standards for the building of pontoon boats. Rules for load and horsepower. 

Pontoon boats are another special case. Other than requiring a Hull Identification Number, the Coast Guard does not regulate load capacity or powering of these boats. If they have inboard gasoline engines they must follow the fuel and electrical regulations and have a certification label. So, are there standards for these boats that you should follow? Yes!

The American Boat and Yacht Council (ABYC) has a standard specifically for pontoon boats. This spells out requirements for:

Safe Loading



The ABYC standard is H-35, Powering and Load Capacity of Pontoon Boats. Contact ABYC for a copy.

613 Third Street, Suite 10
Annapolis, MD 21403
Phone: (410) 990-4460
Fax: (410) 990-4466

Are there other standards for Pontoon Boats?

UK And EU. Pontoon boats are not excluded from the Recreational Craft Directive.


Canadian Office of Boating Safety  has regulations that apply to pontoon boats.

Below is a brief description of how to calculate the safe load for pontoon boats. They are excerpts from the Canadian site and are by no means everything you need to know.  Look at the site, print the PDF and study the standards.

Recommended Maximum Gross Load Calculation The recommended maximum gross load in kilograms marked on a capacity label for a pontoon vessel is determined by the lesser of the following (a) or (b):

(a) Formula for maximum gross load:

GJ = ((Vt X b) -Wv)/2


GL = recommended maximum gross load in kilograms

b = constant buoyancy factor of 1000 kg/m3

Vt = the total volume in cubic metres within all of the pontoons of a vessel

WV = the weight of the vessel in kilograms, including deck, railings, console, seats, and any other permanent structures and fittings. For outboard powered vessels, the outboard engine and related equipment weight from Table 4-2 is excluded. For vessels fitted with permanent fuel tanks the fuel weight must be included.

(b) Maximum gross load per stability test as defined in section 4.5.2 when applicable.

4.5.4 The Recommended Maximum Number of Persons Calculation The recommended maximum number of persons marked on a capacity label for a pontoon vessel is

determined in relation to the volume of pontoons, the volume of the largest compartment of the pontoon, recommended maximum gross load, and engine weight as follows:

(a) For inboard or stern-drive powered vessels:

Persons Capacity =  GL/75  X (1-(Vlc/Vp))

(b) For outboard powered vessels:

Persons Capacity  ={ (GL - We)/75] X (1-(Vlc/Vp))


GL = recommended maximum gross load in kilograms

We = outboard engine and related equipment total weight, as determined from Table 4-2

Vlc = volume of largest compartment, in cubic metres, defined as the largest volume between

separation bulkheads (L4) in any pontoon

Vp = total volume in cubic metres of all pontoons

75 = assumed weight of one adult person in kilograms

Content Continues After Ad The maximum number of persons shall be rounded off to the nearest whole number. If the fraction is less than 0.5, round down to the next whole integer and if the fraction is equal to or greater than 0.5, round up to the next higher whole integer.

4.5.5 The Recommended Maximum Power Calculation The recommended maximum power in kilowatts marked on a capacity label for an outboard powered pontoon vessel is determined in relation to the length of the pontoons squared and the diameter of the pontoons as follows:

MaximumPower kW =  3 X Lh X Lh X Dp


Lh = vessel length of the pontoon in metres as per Figure 0-1

Dp = diameter of the pontoon in metres When the calculated power is not more than 10 kW (15 hp), the power may be rounded up to the next multiple of 1.5 kW (2 hp). When the calculated power is more than 10 kW (15 hp) the power may be rounded up to the next multiple 3.75 kW (5 hp).

Some good Links to Pontoon Boat Information:
Pontoon Houseboat Odyssey

Pontoon Boats Forum

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