Weather Tightness of Hatch

What is Weather tightness of Hatches ? 

           

All Hatch Covers are made of Steel and patented type like Macgregor type steel hatch covers.

To obtain Weather tightness , Piggy-back type Hatch covers or Single pull Hatch covers operated by Electro- hydraulic  motors are fitted with Rubber Packing and Rubber joints/gaskets at the Hatch coaming and hand or automatically operated Cleats. 

In order to close a hatch weather tight – the wheels on which pontoon rests must be lowered down so that the gaskets rests on the lip of the coaming and channel bar.  The jointing fits tightly on the coaming and hatch is made completely weather tight by fitting and securing the cleats. In earlier system on cross joints wedges were also used to achieve weather tightness which is obsolete now.

On container ships, lifting pontoons type covers fitted with strong internal stiffening are commonly used .They have similar arrangement for weather tightness as other patent covers. The means of securing hatches and maintaining their watertightness / weather tightness are tested initially and periodically as per International Load lines and Classification Societies Rules.