A portable fuel tank must have a base/height ratio that won't upset if tilted to how many degrees?

The requirement for the base/height ratio of a portable fuel tank is set to ensure stability when the tank is tilted. A tank must maintain its balance to prevent fuel spillage or accidental leaks that could lead to hazardous situations.

The correct choice indicates that a portable fuel tank is designed to remain stable when tilted up to 35 degrees. This angle represents a practical balance between usability and safety, considering the typical conditions in which portable fuel tanks might be used on boats or during transport.

A base/height ratio that accommodates a 35-degree tilt allows for a reasonable margin of stability. It recognizes the dynamics of movement and the potential for tanks to be subjected to tilting without compromising their structural integrity or safe operation. A higher tilt angle would introduce more risk of the tank becoming unstable, whereas a lower angle may not sufficiently address the practical needs of usage in marine environments.

This balance is key in achieving compliance with safety standards and ensuring the reliable operation of fuel systems while minimizing the risk of fuel hazards.