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The maximum number of people allowed on a boat ( skipper and passengers ) is part of the information present on the CE plate found on board our boats. This number of persons is the maximum load allowed on the boat from which is subtracted the "dead load":
- Consumable tanks filled to 95% of their capacity
- Food
- Personal effects (20 kg per passenger)
- Appendix
The result is then divided by 75 ( the average weight of an adult, 75 kilograms ) to obtain the number of eligible persons on board.
This calculation method is set by the standard ISO 12217-1 which dates from 2015. This is the number that will appear on the CE plate. This calculation method concerns boats put into circulation after 1996. Those that were put on the market in previous years have their maximum number of passengers set by the category of navigation of the boat.
Whether you are sailing (out of a port or a shelter) or at anchor, it is advisable to respect this maximum number of people in order not to put yourself in danger, or simply risk a fine in case of control.
Why is it important not to overload a boat?
To float, a boat uses Archimedes' principle which states an extremely well known law " Any body immersed in a fluid at rest, entirely wetted by it or crossing its free surface, undergoes a vertical force, directed from bottom to top and equal (and opposite) to the weight of the volume of fluid displaced. "
A boat that is overloaded will have more weight than it can move. This imbalance will reduce the stability of the hull and the boat will not be able to float normally. It will then be enough to a catalyst ( a wave, a sudden movement... ) so that the boat can take on water.
At anchor or moored to a pontoon, the risks of overloading also exist. The boat can list by being prevented from recovering naturally ( by its moorings for example ). The energy stored at the time of the movement will not be absorbed by the rope and will return to the hull in counter-reaction, which may aggravate the next cycle.
If the passengers remain perfectly still, it will be enough to break the balance ( bow wave, passenger boarding, tidal current.. ) to create this imbalance. And as in the sea, everything that can move will move ( drink, food, fuel, accessories ) to the lowest point of the boat.
Prevent capsizing
As a preventive measure, the solution is called... storage. Assuming that everything that can be moved on board will be moved. On the other hand, that the movement will always be in the direction of the lowest point of the boat (the side towards the water in case of capsizing). We conclude that it is necessary to fix on board everything that can be fixed and thus reduce the dangerous moving mass.
Passengers are one of these moving masses. If it is unimaginable to strap them on board, it is necessary to ensure that the whole crew is not in the same place at the same time, especially on one side. This is a simple and effective safety measure.
Risk of fine, too
As you can see, respecting the number of people on board a boat remains a major safety issue, as does the maximum acceptable load on board. Not respecting it, extreme or not, could lead the boat to sink and put the whole crew in real danger.
For this reason, the fact of transporting, on a pleasure boat, a number of persons higher than the number of persons foreseen is punishable by a police fine, established by the DDTM or by the Maritime Gendarmerie . And this fine will, in most cases, be accompanied by an obligation to restore the number of people on board the boat ( unload them ) to recover a safe condition of the ship. Sometimes, this judicial fine can be accompanied by an administrative sanction ( suspension or cancellation of the license, confiscation of the boat.. ). In the most extreme case, this offence constitutes a danger to life and is punishable by a fine of 15 000 euros with a maximum penalty of one year in prison .
