Section 6 Double Bottoms

601. General

1. Where bottoms are partially or wholly of double bottom construction, the scantlings of members are to be in accordance with the requirements in 602. to 606.

2. Bottom laminates under the sounding pipes are to be increased in thickness or to be against damages due to sounding rods by suitable means.

3. The thickness of watertight girders and floors, and the scantlings of stiffeners attached to

structural protected

them are

to be in accordance with the respective requirements for the relevant girders and floors, and in ad- dition, in accordance with the requirements for deep tanks in Ch 13.

4. Oiltight cofferdams are to be provided in the double bottom between tanks for those for carrying fresh water such as that for living use, boiler feed water, etc.

carrying oils and which may cause

any trouble when oil mixes therein.

602. Centre Girders

1. Webs of centre girders are to extend the whole length of the bottom as far as practicable.

2. The thickness of webs of centre girders is to be in accordance with the requirements in 201.

603.

Side Girders

1. Where the breadth of ship measured at the top of floors exceeds 4 m , side girders are to be ar- ranged at a suitable spacing.

2. The thickness of webs of side girders is to be in accordance with the requirements in 302.

604. Floors

1. Floors are to be fitted at every frame.

2. The scantlings of floors are to be in accordance with the requirements in 401.

3. Where floors are of spacing.

single skin construction, stiffeners are to be provided on floors at a suitable

4. Floors forming lower

part of bulkheads are to be in accordance with the requirements for water-

tight bulkheads in Ch 12, in addition to those in this chapter.

605. Inner Bottom Laminates

1. The thickness of inner bottom laminates is not to be less than obtained from the following for- mula:

ᾼ Ņ ÌÌǾJĊΡ̓Üᾘ Nmm Ń

where,

Ċ : Spacing of floors (m ).

2. Inner bottom laminates are to be rigidly connected with side shell laminates, bulkhead laminates, etc.

606 Bottom Longitudinals

1. The construction, scantlings and spacing of bottom longitudinals are to be in accordance with the requirements in 501., 502., 503. and Sec 8.

2. The construction and scantling of longitudinals provided on the inner bottom laminates are to be in accordance with the discretion of the Society.