# Length-beam ratio

## Definition

L/B = length divided by beam.

Units: Dimensionless.

Usually, the waterline dimensions LWL and BWL are used for monohulls, or for a single hull of a multihull.

## What it's used for

#### Performance

Larger L/B indicates a slimmer hull. This usually implies less wave-making resistance, and thus more efficient high-speed performance, but also suggests reduced load-carrying ability for a given length.

# Wetted surface area

## Definition

Wetted surface area is the total surface area of the hull and appendages below the waterline. It should include both sides of the rudder and keel, and if the boat has multiple daggerboards, the given wetted surface area usually includes as many foils as would be used simultaneously.

Units: Area (usually square metres or square feet).