IS 4651:1980 Part 5 is the Indian Standard (BIS) for planning and design of ports and harbours - dry docks. This standard outlines the planning, layout, and functional requirements for the design of ports and harbours. It provides critical geometrical parameters for marine infrastructure including approach channels, turning basins, and berths to ensure safe vessel navigation, mooring, and efficient cargo operations.
Details the design and construction requirements for dry docks in port facilities.
Overview
- Status
- Current
- Usage level
- Specialized
- Domain
- Transportation — Coastal and Marine Engineering
- Type
- Code of Practice
Also on InfraLens for IS 4651
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Always incorporate vessel squat (sinkage) and wave-induced heave/pitch when calculating the safe navigable depth of approach channels.
! Master planning should account for the historical trend of increasing vessel sizes (LOA, beam, and draft) to prevent premature obsolescence of port facilities.
! Turning basin dimensions heavily depend on the maneuverability of the design vessel and the continuous availability of assisting tugboats.
Frequently referenced clauses
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International Equivalents
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International Comparison — Coming Soon
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Key Values6
Quick Reference Values
Minimum turning basin diameter (with tugs)1.5 to 2.0 x LOA (Length Overall of design vessel)
Minimum turning basin diameter (without tugs)3.0 to 4.0 x LOA
Approach channel width (single lane)3 to 4 times beam of the largest vessel
Approach channel width (two lane)5 to 7 times beam of the largest vessel
Minimum under keel clearance (UKC)10% of maximum vessel draft
Clearance between moored vessels15m to 25m depending on vessel size
Key Formulas
Required Channel Depth = Maximum Vessel Draft + Squat + Wave Response Allowance + Under Keel Clearance
Tables & Referenced Sections
Key Tables
Table 1 - Recommended Under Keel Clearance (UKC)
Table 2 - Dimensions of Approach Channels
Key Clauses
Clause 4 - Layout of Port Facilities
Clause 5 - Approach Channels
Clause 6 - Turning Basins
Clause 7 - Berthing Structures and Clearances
Frequently Asked Questions4
How is the minimum diameter of a port turning basin determined?+
It should be at least 1.5 to 2.0 times the overall length (LOA) of the largest design vessel if tug assistance is available, and up to 4.0 times LOA without tugs.
What is the recommended width for an approach channel?+
For single-lane traffic, it is typically 3 to 4 times the beam of the largest design vessel; for two-lane traffic, it is 5 to 7 times the beam.
How much Under Keel Clearance (UKC) is required for safe navigation?+
A minimum of 10% of the vessel's maximum draft is generally required, though this must be adjusted for squat, tide, and wave action.
What clearance is required between two ships moored continuously in a line?+
A clearance of 15m to 25m is standard, depending on the sizes of the mooring vessels and their required operational gaps.
QA/QC Inspection Templates
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QA/QC templates coming soon for this code.