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'''Under keel clearance''' (UKC) is the term and calculations used in [[Seamanship|seafaring]] to ensure sufficient [[navigable]] water is available for [[ships]] at sea.<ref name="Gilardoni Presedo 2017">{{cite book | last=Gilardoni | first=Eduardo O. | last2=Presedo | first2=Juan P. | title=Navigation in Shallow Waters | publisher=[[Witherby Publishing Group]] | publication-place=Livingston, Scotland | date=2017 | isbn=978-1-85609-667-6|page=67}}</ref><ref name="ECDISandUKC">{{cite book | title=ECDIS Safety Settings and UKC Management | publisher=[[Witherby Publishing Group]] | publication-place=Livingston, Scotland | date=2017 | isbn=9781914993695}}</ref><ref name="Weintrit 2009">{{cite book | last=Weintrit | first=Adam | title=Marine Navigation and Safety of Sea Transportation | publisher=CRC Press | publication-place=Boca Raton : London | date=2009-06-02 | isbn=978-0-203-86934-5 | oclc=435419166 | page=484}}</ref><ref name="MarineInsight">{{Cite web |url=https://www.marineinsight.com/naval-architecture/what-is-underwater-keel-clearance/|title=What Is Underwater Keel Clearance? |access-date=4 April 2024 |publisher=Marine Insight}}</ref> It is most commonly described as the height and width of available water below the keel ([[Draft (hull)|hull]] of a ship).<ref name="Weintrit 2009"/><ref name="RG">{{Cite web |url=https://www.researchgate.net/publication/328575846_Simplified_approach_to_operationalise_UKC_calculations |title=Simplified approach to operationalise UKC calculations Conference Paper |access-date=4 April 2024 |publisher=PIANC}}</ref> More simply, it can be described as how much water is left between the bottom of the ship and the seabed.<ref name="NI">{{Cite web |url=https://www.nautinst.org/resources-page/all-you-ever-wanted-to-know-about-under-keel-clearance-but-were-afraid-to-ask.html |title=All you ever wanted to know about Under Keel Clearance but were afraid to ask |access-date=4 April 2024 |publisher=Nautical Institute}}</ref>
'''Under keel clearance''' (UKC) is the term and calculations used in [[Seamanship|seafaring]] to ensure sufficient [[navigable]] water is available for [[ships]] at sea.<ref name="Gilardoni Presedo 2017">{{cite book | last=Gilardoni | first=Eduardo O. | last2=Presedo | first2=Juan P. | title=Navigation in Shallow Waters | publisher=[[Witherby Publishing Group]] | publication-place=Livingston, Scotland | date=2017 | isbn=978-1-85609-667-6|page=67}}</ref><ref name="ECDISandUKC">{{cite book | title=ECDIS Safety Settings and UKC Management | publisher=[[Witherby Publishing Group]] | publication-place=Livingston, Scotland | date=2017 | isbn=9781914993695}}</ref><ref name="Weintrit 2009">{{cite book | last=Weintrit | first=Adam | title=Marine Navigation and Safety of Sea Transportation | publisher=CRC Press | publication-place=Boca Raton : London | date=2009-06-02 | isbn=978-0-203-86934-5 | oclc=435419166 | page=484}}</ref><ref name="MarineInsight">{{Cite web |url=https://www.marineinsight.com/naval-architecture/what-is-underwater-keel-clearance/|title=What Is Underwater Keel Clearance? |access-date=4 April 2024 |publisher=Marine Insight}}</ref> It is most commonly described as the height and width of available water below the keel ([[Draft (hull)|hull]] of a ship.<ref name="Weintrit 2009"/><ref name="RG">{{Cite web |url=https://www.researchgate.net/publication/328575846_Simplified_approach_to_operationalise_UKC_calculations |title=Simplified approach to operationalise UKC calculations Conference Paper |access-date=4 April 2024 |publisher=PIANC}}</ref> More simply, it can be described as how much water is left between the bottom of the ship and the seabed.<ref name="NI">{{Cite web |url=https://www.nautinst.org/resources-page/all-you-ever-wanted-to-know-about-under-keel-clearance-but-were-afraid-to-ask.html |title=All you ever wanted to know about Under Keel Clearance but were afraid to ask |access-date=4 April 2024 |publisher=Nautical Institute}}</ref>


[[Master mariner]]s should ensure there is sufficient UKC for their ships and ports should ensure sufficient UKC for the type and draft of ships due to arrive in the port.<ref name="NI"/> Ships typically calculate their UKC to meet criteria for ports to minimise the risk of maritime incidents.<ref name="NI"/>
[[Master mariner]]s should ensure there is sufficient UKC for their [[ships]] and [[ports]] should ensure sufficient UKC for the type and draft of ships due to arrive in the port.<ref name="NI"/> Ships typically calculate their UKC to meet criteria for ports to minimise the risk of maritime incidents.<ref name="NI"/>


==Methods of calculation==
==Methods of calculation==
At a basic level, it is typically calculated in metres using the formula: Draught - Height of [[Tide]] = UKC.<ref name="Weintrit 2009"/> Ship Masters and deck officers can obtain the depth of water from [[Electronic navigational chart]]s.<ref name="ECDISandUKC"/>
At a basic level, it is typically calculated in metres using the formula: [[Chart datum|Charted Depth]] - [[Draft (hull)|Draft]] -/+ Height of [[Tide]] = UKC.<ref name="Weintrit 2009"/> Ship Masters and deck officers can obtain the depth of water from [[Electronic navigational chart]]s.<ref name="ECDISandUKC"/>


Computer systems and software can be used to manage and calculate UKC for ships and ports.<ref name="MarExec">{{Cite web|url=https://maritime-executive.com/corporate/under-keel-clearance-technology-wins-international-award |title=Under Keel Clearance Technology Wins International Award |access-date=4 April 2024 |publisher=Maritime Executive}}</ref><ref name="DCN">{{Cite web|url=https://www.thedcn.com.au/news/ports/under-keel-clearance-system-upgrade-for-bunbury/ |title=Under Keel Clearance System Upgrade for Bunbury |access-date=4 April 2024 |publisher=Daily Cargo News}}</ref> These include systems that dynamically manage UKC using models, forecasting and calculations.<ref name="HarbourMaster">{{Cite web|url=https://harbourmaster.org/sponsors/omc |title=OMC |access-date=4 April 2024 |publisher=International Harbour Masters Association}}</ref>
Computer systems and software can be used to manage and calculate UKC for ships and ports.<ref name="MarExec">{{Cite web|url=https://maritime-executive.com/corporate/under-keel-clearance-technology-wins-international-award |title=Under Keel Clearance Technology Wins International Award |access-date=4 April 2024 |publisher=Maritime Executive}}</ref><ref name="DCN">{{Cite web|url=https://www.thedcn.com.au/news/ports/under-keel-clearance-system-upgrade-for-bunbury/ |title=Under Keel Clearance System Upgrade for Bunbury |access-date=4 April 2024 |publisher=Daily Cargo News}}</ref> These include systems that dynamically manage UKC using models, forecasting and calculations.<ref name="HarbourMaster">{{Cite web|url=https://harbourmaster.org/sponsors/omc |title=OMC |access-date=4 April 2024 |publisher=International Harbour Masters Association}}</ref>

Revision as of 22:21, 3 April 2024

Under keel clearance (UKC) is the term and calculations used in seafaring to ensure sufficient navigable water is available for ships at sea.[1][2][3][4] It is most commonly described as the height and width of available water below the keel (hull of a ship.[3][5] More simply, it can be described as how much water is left between the bottom of the ship and the seabed.[6]

Master mariners should ensure there is sufficient UKC for their ships and ports should ensure sufficient UKC for the type and draft of ships due to arrive in the port.[6] Ships typically calculate their UKC to meet criteria for ports to minimise the risk of maritime incidents.[6]

Methods of calculation

At a basic level, it is typically calculated in metres using the formula: Charted Depth - Draft -/+ Height of Tide = UKC.[3] Ship Masters and deck officers can obtain the depth of water from Electronic navigational charts.[2]

Computer systems and software can be used to manage and calculate UKC for ships and ports.[7][8] These include systems that dynamically manage UKC using models, forecasting and calculations.[9]

The International Hydrographic Organization (IHO) sets a Standard for UKC Management for software and systems: S-129 Under Keel Clearance Management.[10]

Uses and requirements

For US waters, the US Code of Federal Regulations require ships and their Masters to calculate UKC based on the ship's deepest navigational draft.{CodeFedReg |33|157|450}} The regulations require the Master to discuss the UKC calculation with the Maritime pilot as the ship approaches US ports/waters.33 CFR 157.450

The Australian Maritime Safety Authority state that maintaining adequate UKC is important for safe navigation in the Torres Strait.[11]

Inadequate UKC, caused by shallow water and squat may lead to ship groundings.[12] In 2019, the UK Marine Accident Investigation Branch found that indequate UKC contributed towards the grounding of the ro/ro freight ferry MS Stena Performer.[12]

Changes in water level may cause issues with adequate UKC for ships. For example, recent water level reductions in the Panama Canal have reduced UKC for ships meaning some ships are not able to transit the canal.[13][14]

References

  1. ^ Gilardoni, Eduardo O.; Presedo, Juan P. (2017). Navigation in Shallow Waters. Livingston, Scotland: Witherby Publishing Group. p. 67. ISBN 978-1-85609-667-6.
  2. ^ a b ECDIS Safety Settings and UKC Management. Livingston, Scotland: Witherby Publishing Group. 2017. ISBN 9781914993695.
  3. ^ a b c Weintrit, Adam (2009-06-02). Marine Navigation and Safety of Sea Transportation. Boca Raton : London: CRC Press. p. 484. ISBN 978-0-203-86934-5. OCLC 435419166.
  4. ^ "What Is Underwater Keel Clearance?". Marine Insight. Retrieved 4 April 2024.
  5. ^ "Simplified approach to operationalise UKC calculations Conference Paper". PIANC. Retrieved 4 April 2024.
  6. ^ a b c "All you ever wanted to know about Under Keel Clearance but were afraid to ask". Nautical Institute. Retrieved 4 April 2024.
  7. ^ "Under Keel Clearance Technology Wins International Award". Maritime Executive. Retrieved 4 April 2024.
  8. ^ "Under Keel Clearance System Upgrade for Bunbury". Daily Cargo News. Retrieved 4 April 2024.
  9. ^ "OMC". International Harbour Masters Association. Retrieved 4 April 2024.
  10. ^ "Dynamic Draft and Under Keel Clearance". International Hydrographic Organization (IHO). Retrieved 4 April 2024.
  11. ^ "Under Keel Clearance Management System Fact Sheet". Australian Maritime Safety Authority. Retrieved 4 April 2024.
  12. ^ a b "MAIB: Shallow Water Effects Contributed to Ro/Ro's Grounding". Maritime Executive. Retrieved 4 April 2024.
  13. ^ "Panama Canal water levels cause long-term concern". Riviera. Retrieved 4 April 2024.
  14. ^ "Panama Canal Drought Slows Cargo Traffic". The New York Times. Retrieved 4 April 2024.
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