Section 2 Construction and Arrangement

201. Construction

The hopper type structures are to be arranged

Fig 10.1 and classified with following types.

1. one or two hopper hold type in midship

2. bucket well type

with transverse or longitudinal framing system as

Ch 1 0

Fig 10.1 Hopper construction

202. Arrangement

1. The hopper type dredgers, since they have many structural discontinuities, are to be specially con- sidered for the structural continuity.

2. The hopper holds are to be provided with weirs for freeing the water or mud.

3. In case, where the dredger is operating with hopper barges, the fenders are to be provided properly for the protection of shell plating. The places where the fenders are fitted are to be re- inforced in accordance with the approval of the society.

203. Discontinuity of transverse members

1. The cellular keel is to be rigidly connected to the transverse ring.

2. The upper parts of cellular keel are to be connected with decks or trunk structures by strong beams or centerline wash bulkhead.

3. The structural continuity of hopper holds including longitudinal bulkhead and cellular keel is to be sufficiently considered.

204. Discontinuity of longitudinal members

1. The end of longitudinal bulkhead is to be extended by large brackets at forward and aftward of hopper holds.

2. The ends of forward and aftward of cellular keel are to be provided with brackets which have the same depth of the keel.

3. The both sides of trunk are to be extended with 1.5 times or more the height of trunk to the ends of hopper hold.

4. Special attention is to be made for the other structural arrangements.