2. What Is Marine Manhole Cover Type B 

Marine manhole covers type B is basically a hatch used to access tanks.

With its structural strengthening design, users can enter the inside of tanks for inspection.

Compared to Manhole Cover Type A, Type B has more thickness on coaming and bolts are placed longer.

So Type B provides you stronger strength and better sealing.

3. Configuration of Marine Manhole Cover Type B 

3.1 Cover

The cover prevents external loads from acting on the opening.

Cover resists tank pressure and loads while underway.

3.2 Ring

The ring reinforces the opening and mates to the tank.

3.3 Bolt / Nut

Bolts distribute the load across the cover evenly.

Therefore, gasket seals effectively when compressed.

3.4 Gasket

Gaskets are typically rubber or composite to prevent leaks.

These stops liquids from leaking and vapor from escaping.

4. Materials

Typical materials Marine Manhole Covers Type B are made of:

• Carbon steel
• Stainless steel (304/316)
• Marine-grade rubber gasket
• Corrosion resistant bolts

Stainless steel will resist corrosion longer in offshore conditions.

5. Leak Proof Structure and Safety

Marine Manhole Covers Type B features compression sealing system.

Even pressure created by the compression of gasket between cover and coaming ring.

Also evenly pressure secured by bolt system.

So there is no leakage of oil, water or other liquids.

6. Characteristics

• High Strength
• Excellent sealing performance
• Corrosion resistance material
• Allow simple access for inspection and maintenances
• Long service life

7. Applied Marine Tank

Apply to fuel oil tank,

ballast water tank, lubricating oil tank, freshwater tank or cargo tank.

Safe and easy access for crewmember inspection.

8. Marine Standards Compliance

Marine Manhole Covers Type B is made to international standards.

IMO compliant for design and testing.

Referenced ISO standards for manufacturing from

The International Organization for Standardization.

Products certified to pass international marine safety standards.

9. Benefits of ZHENXING Ship

ZHENXING Ship focuses on manufacturing marine doors, marine hatches, marine windows and marine tank covers.

Benefits of using ZHENXING Ship products listed on marinedoorswindow.com:

Includes professional marine engineered designs

Subject to quality control measures

Offers custom sizes and materials

Reasonable prices at an international level.

10. Fabrication process and quality control

The fabrication process consists of following steps.

Cutting steel plates to required dimension

Welding the coaming ring and structure together

Machine bolt holes to dimension

Apply seal gasket and coating

Inspection for marine standards

11. Options

Different options are available for Marine Manhole Covers Type B to fit into ship needs.

Following are some options.

Size of the diameter and opening.

Material.

Types of gasket.

Pattern of bolts.

So cover can be fitted into different tanks.

12. Maintenance Instructions

Regularly check gaskets

Check bolts looseness

Clean sealing surface

Lubricate movable parts

Pay attention to maintenance, it can last long.

For marine safety and engineering standards:

• International Maritime Organization
• International Organization for Standardization

13. FAQ

13.1 What is Marine Manhole Covers Type B made of?

Marine tank access hatch with reinforcement.

13.2 Where does the Marine Manhole Cover Type B goes?

Installed in fuel tank, ballast tank, freshwater tank, lubricating oil tank.

13.3 Does ZHENXING Ship customize the cover?

Yes, we can customize the size, material and gasket of Marine Manhole Covers Type B.

13.4 Where is the place to buy Marine Manhole Covers Type B?

marinedoorswindow.

14. Summary

Marine Manhole Cover Type B is used to provide safe access to marine tanks. Provides reliable sealing performance.

ZHENXING Ship exports high-quality Marine Manhole Cover Type B products worldwide. Customers can buy various professional marine tank access hatches on marinedoorswindow.

At ZHENXING Ship, you are guaranteed to get corrosion-proof, long-lasting and reliable marine manhole covers.