Matter is defined as a substance made up of particles that has weight and can occupy space. There are three main states of matter which include:

Solid: They have their particles vibrate in their fixed positions.
Liquid: The particles are generally slightly further apart than in a solids; and
Gas: particles are widely spaced and tend to be only slightly attracted to each other.
The windsurfer, his board, and his surroundings is made up of particles that are tightly packed together and vibrate in their fixed positions.

Therefore, the components that make up the windsurfer, his board, and his surroundings is matter.