Directive of the European Parliament and of the Council of 12 December 2006 laying down technical requirements for inland waterway vessels and repealing Council Directive 82/714/EEC (2006/87/EC) (repealed)

Article 17.07 Confirmation of stability

1. It shall be confirmed that, when taking into account the loads applied during operation of the working gear and whilst under way, the residual freeboard and the residual safety clearance are sufficient. For that purpose the sum of the trim and heeling angles shall not exceed 10° and the bottom of the float shall not emerge.

2. Confirmation of stability shall include the following data and documents:

(a) scale drawings of floats and working gear and the detailed data relating to these that are needed to confirm stability, such as content of the tanks, openings providing access to the inside of the vessel;

(b) hydrostatic data or curves;

(c) righting lever curves for static-stability to the extent required in accordance with paragraph 5 below or Article 17.08;

(d) description of the operating conditions together with the corresponding data concerning weight and centre of gravity, including its unladen state and the equipment situation as regards transport;

(e) calculation of the heeling, trimming and righting moments, with a specification of the trim and heeling angles and the corresponding residual freeboard and residual safety clearances;

(f) a compilation of the results of the calculation with a specification of the limits for operation and the maximum loads.

3. Confirmation of stability shall be based on at least the following load assumptions:

(a) specific mass of the dredging products for dredgers:

• (a) sands and gravels: 1,5 t/m³,

• very wet sands: 2,0 t/m³,

• soil, on average: 1,8 t/m³,

• mixture of sand and water in the ducts: 1,3 t/m³;

(b) for clamshell dredgers, the values given under point (a) shall be increased by 15 %;

(c) for hydraulic dredgers the maximum lifting power shall be considered.

4.1. Confirmation of stability shall take account of the moments resulting from:

(a) load;

(b) asymmetric structure;

(c) wind pressure;

(d) turning whilst under way of self-propelled floating equipment;

(e) cross current, if necessary;

(f) ballast and provisions;

(g) deck loads and, where appropriate, cargo;

(h) free surfaces of liquids;

(i) inertia forces;

(j) other mechanical equipment.

The moments which may act simultaneously shall be added up.

4.2. The moment caused by the wind pressure shall be calculated in accordance with the following formula:

where:

c

=

shape-dependent coefficient of resistance

For frameworks c = 1,2 and for solid-section beams c = 1,6. Both values take account of gusts of wind.

The whole area encompassed by the contour line of the framework shall be taken to be the surface area exposed to the wind.

p_w

=

specific wind pressure; this shall uniformly be taken to be 0,25 kN/m²;

A

=

lateral plane above the plane of maximum draught in m²;

l_w

=

distance from the centre of area of the lateral plane A from the plane of maximum draught, in m.

4.3. In order to determine the moments due to turning whilst under way according toparagraph 4.1(d) for self-propelled floating equipment, the formula set out in Article 15.03 (6) shall be used.

4.4. The moment resulting from cross current according to paragraph 4.1(e) shall be taken into account only for floating equipment which is anchored or moored across the current while operating.

4.5. The least favourable extent of tank filling from the point of view of stability shall be determined and the corresponding moment introduced into the calculation when calculating the moments resulting from liquid ballast and liquid provisions according to paragraph 4.1(f).

4.6. The moment resulting from inertia forces according to paragraph 4.1(i) shall be given due consideration if the movements of the load and the working gear are likely to affect stability.

5. The righting moments for floats with vertical side walls may be calculated using the following formula

• M_a = 10 · D · · sinφ (kNm)

where:

=

metacentric height, in m;

φ

=

heeling angle in degrees.

That formula shall apply up to heeling angles of 10° or up to a heeling angle corresponding to immersion of the edge of the deck or emergence of the edge of the bottom; the smallest angle shall be decisive. The formula may be applied to slanting side walls up to heeling angles of 5°; the limit conditions set out in paragraphs 3 and 4 shall also apply.

If the particular shape of the float(s) does not permit such simplification the righting lever curves according to paragraph 2(c) shall be required.