What is Trimming procedure as per IMSBC code ? |

What is Trimming procedure as per IMSBC code ?

Trimming procedures

Trimming a cargo reduces the likelihood of the cargo shifting and minimizes the air entering the cargo. Air entering the cargo could lead to spontaneous heating. To minimize these risks, cargoes shall be trimmed reasonably level, as necessary.

Cargo spaces shall be as full as practicable without resulting in excessive loading on the bottom structure or ’tween-deck to prevent sliding of a solid bulk cargo.

Due consideration shall be given to the amount of a solid bulk cargo in each cargo space, taking into account the possibility of shifting and longitudinal moments and forces of the ship.

Cargo shall be spread as widely as practicable to the boundary of the cargo space. Alternate hold loading restrictions, as required by SOLAS  chapter XII, may also need to be taken into account.

The master has the right to require that the cargo be trimmed level, where there is any concern regarding stability based upon the information available, taking into account the characteristics of the ship and the intended voyage.

For trimming purposes, solid bulk cargoes can be categorized as cohesive or non cohesive.

The angle of repose is a characteristic of non-cohesive bulk cargoes which is indicative of cargo stability and has been included in the individual schedules for non cohesive cargoes.

Non-cohesive bulk cargoes having an angle of repose less than or equal to 30°

These cargoes, which flow freely like grain, shall be carried according to the provisions applicable to the stowage of grain cargoes. The bulk density of the cargo shall be taken into account when determining:

  1. The scantlings and securing arrangements of divisions and bin bulkheads;
  2. The stability effect of free cargo surfaces.
Non-cohesive bulk cargoes having an angle of repose greater than 30° to 35° inclusive
  1. the unevenness of the cargo surface measured as the vertical distance (Δh) between the highest and lowest levels of the cargo surface shall not exceed B/10, where B is the beam of the ship in metres, with a maximum allowable Δh = 1.5 m; or
  2. loading is carried out using trimming equipment approved by the competent authority.
Non-cohesive bulk cargoes having an angle of repose greater than 35°
  1. The unevenness of the cargo surface measured as the vertical distance (Δh) between the highest and lowest levels of the cargo surface shall not exceed B/10, where B is the beam of the ship in metres, with a maximum allowable Δh = 2 m; or
  2. loading is carried out using trimming equipment approved by the competent authority.

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