Scantlings for an unusual design

[sorenfdk]

I have been asked if it is possible to obtain CE-approval of a rather unusual design.

The name of the yacht is Centerline 40. LOA is 12.15 meter. Approximately 10 have been built during the last ten years. The builder/designer has passed away, and he left no drawings/calculations. A new builder, who owns a Centerline 40, is thinking about taking up production.

The design is unusual because there are no floors to take the loads from the keel! Instead, the keel is attached to a large (L x B = approximately 1.5 meter x 1.0 meter) steelplate, which is laminated to the inside of the bottom shell. In fact, it is encapsulated in the bottom laminate, sort of like the core of a sandwich laminate, but the entire hull is single laminate. The bottom of the hull is completely flat.

My idea is to treat the plate as one single floor, and then do the traditional calculations, but I'm not at all sure whether this is the way to go.

Any better ideas?

[Paul Kotzebue]

The laminate should be treated as a fiberglass and steel composite in way of the steel plate. The potential problem I see is at the outboard edge of the steel plate. Floors that support a ballast keel should end at a longitudinal girder strong enough to support the keel load plus the hydrostatic load, or they should attach to a transverse frame the runs to the gunwhale. With the steel plate arrangement, the transverse loads may not be properly supported by the surrounding structure.