Ballast takes many forms. The simplest form of ballast used in small day sailers is so-called live ballast, or the weight of the crew. By sitting on the windward side of the hull, the heeling moment must lift the weight of the crew.
The Principal-Agent Relationship. A principal-agent relationship is an arrangement between two or more individuals. Specifically, the agent of the relationship performs a task on behalf of the principal. This is often due to different degrees of knowledge and skills.
The principal-agent problem is broad enough one that it can be found in a wide variety of contexts. An example of how the principal-agent problem occurs between ratings agencies and the companies (the principals) that hire them to set a credit rating.