Simplify the following text for a Grade 10 native English-speaking person.
Original: ( ex : BWL is the maximum beam at the waterline ) : \* Depth or moulded depth ( D ) is the vertical distance measured from the top of the keel to the underside of the upper deck at side .
Simplified: ( ex : BWL is the maximum beam at the waterline ) : \* Depth ( D ) is the vertical distance from the bottom of the hull to the uppermost edge at the side .