1,Usage: this product is applied to various types of ship oil, water tanks,
cofferdams and cabinet in the manhole opening mounted on the bottom, deck,
bulkhead flat parts. And this product is suitable for ships watertight and oil tight manhole cover,
not suitable for boilers and pressure vessels. The cover plate is arranged at upper end of the
handle, the connecting device is connceted with the cover plate of the outer end face if the cylinder,
which is connected with the exterior wall. The utility model, can prevent the unloading cover loss,
while also reducing the ship welding workload, ensuring product integrity, and save the cost
2,Used for the ship watertight and oil tight manhole cover
3,Smooth surface without cracks , good wear and corrosion resistance,never rust
