Section 1 General

101. Scope

This chapter applies to the determination of design pressures and stresses, and to the determination of the scantlings, including internal structural members of monohull small craft constructed from fi- bre-reinforced plastics, aluminium or steel alloys, glued wood or other suitable craft building materi- al, with a length of hull, ÄĂ, between 2.5 m and 24 m. It only applies to crafts in the intact

condition. And it only applies to craft with a maximum speed ≤ 50 knots in

ŶÄǼÆ

conditions.

102. Terms and definitions

For the purposes of this chapter, the following terms and definitions apply.

1. Displacement craft

Craft whose maximum speed in flat water and such that

ŶÄǼÆ

conditions, declared by its manufacturer, is

J Ã Ĥ È

FĬJÄ BÄ F

2. Displacement mode

Mode of running of a craft in the sea such that its mass is mainly supported by buoyancy forces

3. Planing craft

Craft whose maximum speed in flat water and such that

ŶÄǼÆ

conditions, declared by its manufacturer, is

J Ã ≥ È

FĬJÄ BÄ F

4. Planing mode

Mode of running of a craft in the sea such that its mass is significantly supported by forces com- ing from dynamic lift due to speed in the water

103. Areas

1. General

The hull, deck and superstructure are divided into various areas: bottom, side, decks and super- structures (see Fig 4.1).

(1) Bottom areas

For all craft, bottom pressure applies up to waterline (see following the above definition is considered as bottom.

Fig 4.1). The part of the transom

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1. bottom (hatched area)

2. side

3. deck

4. superstructures

5. superstructure top

6. hard chine

Fig 4.1 Definitions of areas, and panel height above waterline

(2) Side areas

The extent of the side pressure area, which includes the transom, considered as belonging to the bottom area.

(3) Decks and superstructures

Deck areas are parts of the deck exposed to weather and where Cockpit bottom and top of benches and seating areas are included.

is the part of the hull not

persons are liable to walk.

Superstructure areas include all areas above deck level. Table 4.3 lists the different super-

structure types.

(4) Panel fully in one area or across two areas

The general situation is as follows:

(A) Where the plate panel or stiffener is fully within a specified design area, e.g. bottom, side, deck, superstructures, etc., its design pressure shall be determined at the middle of the panel or at mid-length of the stiffener;

(B) Where the plate panel or stiffener extends over both bottom area and side area, its design pressure shall be determined as a constant pressure over the entire design area, calculated as a weighted average between the two pressures.

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