Ship Bottom Plug

Ship Bottom Plug


Ship Bottom Plug is a marine drainage component installed at the bottom of ships for hull drainage, inspection, and maintenance purposes.

Designed for commercial vessels and marine engineering applications, the bottom plug provides a reliable sealing function to prevent seawater leakage during normal operation while allowing controlled drainage when required.

Ship Bottom Plug is commonly installed at the lowest points of:

  • Ship hull structures

  • Engine rooms

  • Ballast compartments

  • Fresh water tanks

  • Drainage pipelines

  • Marine equipment systems

It is widely used on:

  • Cargo ships

  • Bulk carriers

  • Container ships

  • Tankers

  • Workboats

  • Offshore vessels

Overview

Working Principle of Ship Bottom Plug

Ship Bottom Plug works as a removable sealing device installed on the bottom area of a vessel.

During normal navigation:

  1. The plug remains tightly installed.

  2. The sealing surface prevents seawater penetration.

  3. The hull structure remains watertight.

During maintenance:

  1. The plug is removed manually.

  2. Accumulated water inside the hull is discharged.

  3. The plug can be reinstalled after drainage.

Main Components of Ship Bottom Plug

ComponentFunction
Plug BodyMain sealing component
Threaded ShaftConnects with hull drain fitting
Hex HeadAllows tightening and removal
Sealing SurfacePrevents leakage
Gasket / WasherImproves watertight performance

Applicable Standards of Ship Bottom Plug

Standard CategoryApplicable Standards
Marine Drain Plug StandardCB/T4248-2013
Shipbuilding StandardsCB/T Series
Chinese Marine StandardsGB/T Standards
Material StandardsASTM / EN Standards
Quality ManagementISO 9001
Classification RequirementsCCS / ABS / DNV / LR

Types of Ship Bottom Plug

Threaded Ship Bottom Plug:The most common type used for ship hull drainage.

Features:

  • Threaded connection

  • Easy replacement

  • Reliable sealing

Applications:

  • Commercial vessels

  • Ship repair projects

  • New vessel construction

Flanged Ship Bottom Plug:  Installed with flange connection

Features:

  • Strong connection

  • Suitable for larger drainage openings

  • Higher mechanical strength

Applications:

  • Large vessels

  • Marine equipment systems

Drain Screw Plug Type: Compact design for drainage openings.

Applications:

  • Engine room drainage

  • Tank drainage

  • Auxiliary systems

Material Selection of Ship Bottom Plug

MaterialFeaturesApplications
Stainless SteelExcellent seawater corrosion resistanceOffshore vessels
BrassGood corrosion resistance and machinabilityGeneral ships
BronzeTraditional marine materialShipbuilding applications
Aluminum AlloyLightweightSmall vessels
SteelHigh strengthHeavy-duty applications

Common Material Standards

MaterialStandard
Stainless SteelASTM A276
BrassASTM B16
BronzeASTM B62
Aluminum AlloyASTM B209
SteelASTM A216

Technical Specifications of Ship Bottom Plug

ItemSpecification
Product NameShip Bottom Plug
ApplicationShip Hull Drainage
Installation PositionVessel Bottom / Hull Drain Opening
Connection TypeThreaded
MediumWater / Seawater
Material OptionsStainless Steel / Brass / Bronze
Sealing TypeGasket / Washer
StandardCB/T4248-2013 Available

Advantages of Ship Bottom Plug

FeatureBenefit
Watertight DesignPrevents seawater leakage
Marine MaterialsSuitable for harsh environments
Easy MaintenanceSimple removal and replacement
Compact StructureSaves installation space
Reliable SealingImproves vessel safety

Applications of Ship Bottom Plug

SystemFunction
Hull Drainage SystemRemoves internal water
Engine RoomDrains accumulated water
Ballast TankProvides maintenance drainage
Ship RepairAllows hull inspection
Marine EquipmentSeals drainage openings


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