Section 4 Hull Girder Strength

401. General

1. The requirements, not mentioned in following Par. are to be in accordance with requirements in

Ch3, Sec 4

2. When calculating the section modulus of a composite structure possible differences in the elasticity modulus of various structural members are to be taken into account. The stresses are to be cor- rected accordingly.

402. Deck corners

Moulded deck line, rounded sheer strake, sheer strake and stringer plate are as defined in Fig 3.5.3.

Fig 3.5.3 Deck corners

403. Vertical bending strength

The vertical bending stresses of FRP craft are in accordance with requirements in Ch 3 and s-val- ues are defined as follows.

o : In general.

o N mm o

N mm

: For hydrofoil on foils.

: In slowed-down condition for planing craft.

404. Allowable strength

1. If direct calculation using the full stiffness and strength properties of the laminate are carried out the procedure is to be followed by Society approval.

2. When a simplified calculation method is used for constructions complying with 104. Par 2 the to- tal normal stresses in the two main directions shall comply with the requirements of 503. Par 5, 603. Par 3 and 604. Par 1. However, in plane laminate shear stresses shall be less than 0.25 times of ultimate shear stress.