Overview

The parametric bulb is a very simple control polygon of a fourth order B-Spline Surface representing a basic bulbous bow. Nine parameters define various dimensions of bulb definition control polygon. Once enabled the following parameters are used to define the shape of the mesh:

Bulb Length and Tail Length

The BulbLength parameter defines the protrusion of the bulb forward of F.P. TailLength defines the extent of the bulb mesh behind FP. Note that the final aft extent of the bulb is dependant on the intersection of the hull and bulb surfaces.

Beam and Tail Beam

The Beam parameter defines the width of the mesh in the main portion of the bulb. Tail beam defines the width of the bulb in the trailing portion of the bulb surface.

Point Height

The PointHeight parameter defines the height of the forward extent of the bulb. The parameter controls the midpoint of the forward most control points. The distance between the two points can be controlled with the Separation parameter affecting the radius of the bulb. The effect is carried back in to the main portion of the bulb. In the tail of the bulb, a separate parameter, TailHeight, controls the control polygon mesh in a similar way.

Tail Height

The TailHeight parameter defines the height of the tail portion of the bulb. A similar parameter, PointHeight, controls the control polygon mesh in a similar way.

Bar Width

The BarWidth parameter controls the length of tangent into the baseline.

Separation

The separation parameter specifies the distance between the control points defining the forward extent of the bulb. This distance is carried back into the main part of the bulb. The Separation Parameter works in conjunction with PointHeight parameter controls the position of the midpoint of the Separation distance

Soft Nose

The softnose parameter controls the tangent of the surface across the centre plane. The parameter affects the radius and sharpness of the waterlines as they approach the centre plane.