Section 4 Shell Laminates for End Parts

401. Thickness of Shell Laminates for End Parts

1. The thickness of shell laminates of single skin construction may be gradually reduced beyond the midship part and it may be 0.85 times the thickness of shell laminates amidships for end parts.

2. Shell laminates of sandwich construction beyond the midship part are to be of the same con- struction as that for the midship part.

3. For the part where subjected to local loads such as propeller pressure, etc., the shell laminates are to be properly strengthened.

402. Strengthened Bottom Forward

The strengthened bottom forward is the part of flat bottom forward from the position specified in the following. The flat bottom is the bottom whose slope measured at the respective athwartship sections (See Fig 6.1) is not more than 15 degrees.

Đ

(1) Where

(2) Where

ÜΡ̓ÜÃ Đ

ÜΡ̓ÜÃ

is not more than 1.5 : 0.25 Ã from the fore end

exceeds 1.5 : 0.3 Ã from the fore end

Where Đ is the designed speed in knots which the ship with clean bottom can attain at the max- imum continuous output on calm sea in loading condition corresponding to the designed maximum load line (hereinafter referred to as "the full load condition in the Rules).

Fig 6.1 Slope of Bottom

403.

Shell Laminates at the Strengthened Bottom Forward

1. The thickness of shell laminates at the strengthened bottom forward of single skin construction is not to be less than obtained from the following formula:

ᾼ Ņ ǼĊΡ̓ÜÃ Nmm Ń

where,

Ǽ : Coefficient given in Table 6.2. However, for the intermediate value of ft,

Ǽ is to be ob-

tained by linear interpolation.

Ċ : Spacing of frames, or spacing of girders or longitudinal shell stiffeners, whichever is smaller(m )

ft : Spacing of frames, or spacing of girders or longitudinal shell stiffeners, whichever is great- er(m ), divided by Ċ .

Table 6.2 Values of Ǽ

2. The thickness of shell laminates at strengthened bottom forward of sandwich construction is not to be less than obtained from the formula specified in 303. 1. However, in application of the formula, ǼĮ is to be taken as 1.8 times that given in Table 6.1 and ᾼᾚ as the thickness of shell laminates specified in 303.

3. In FRP Ships whose à is less than 20 m and Đ is less than 14 knots or in FRP Ships which are deemed by the Society to have sufficient bow draught, the thickness specified in the preceding 1 and 2 may be properly reduced.