Hatch ways & Hatch Coaming

What is Hatchways and Hatch Coaming ? 

Hatch ways :-  Large openings are cut in main deck for cargo operation on Dry cargo vessels Which is  known as Hatch ways. Hatch ways extend upto one third of beam on General cargo, Bulk carriers and may be more in case of Container ships.                                                    

Special arrangement must be made to compensate for loss of strength due to the structural discontinuity caused by these large openings.                                                                           

1. Deep hatch beams are fitted at the forward and aft ends of hatchway.     

2. Deep hatch side girders are fitted on the sides of hatch openings. Half hatch beams are attached to the side girders as required.       

3. The intersection of hatch end beams and hatch side girders are also further strengthened by fitting of gusset plate.      

4. Hatch corners are always rounded to avoid concentration of stresses which can cause crack on deck or fracture of strengthening members.         

5. The deck plating in the vicinity of these openings are usually doubled. 

Hatch Coamings :-  Hatchways are fenced all around by fitting Hatch Coamings made of steel. They are  stiffened on upper edge by a horizontal stiffener not less than 180mm in depth. Additional support is given by brackets or Stays at interval of not more than 3m. Height of Hatch Coaming on exposed freeboard deck should be atleast 600mm within forward 0.25 L of the ship and atleast 450mm on exposed superstructure decks abaft 0.25 L of the ship. Side coamings are to extend to at least the lower edge of the deck beams.