Eliminating discharges in oil/sea interfaces

A return to seawater lubricated propeller shaft systems for commercial ships

Presented byGeorge Morrison, Thordon Bearings

BIMCO Driving Maritime Environmental & Efficiency Management Seminar

2 June 2015

Overview• Problems with oil/sea interfaces in

propeller shaft lines• Regulations impacting ship owners

US EPA – Vessel General Permit Polar Code

• Solutions Air Seals / EAL’s Seawater lubricated shaft lines

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Oil discharges from commercial ships… a serious problem

• Approximately 96% of commercial ships use oil lubricated metal propeller shaft bearings.1

• Total worldwide use of lubricants from operational leaks and discharges estimated to be about 130 million to 244 million litres annually. Equivalent to 5 Exxon Valdez oil spills.2

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1 Data related to Propulsion systems, IHS Fairplay database

2 Etkin, Dagmar Schmidt. Environmental Research Consulting “Worldwide Analysis of In-Port Vessel Operational Lubricant ,” Arctic and Marine Oilspill Program Technical Seminar of Environment Canada, 8 June 2010, Halifax, Canada

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Propeller Shafts Lubricated With Oil

• Typical stern tube system has 1500 to 3000 litres of mineral oil

OIL

Oil to seainterface

Oil Lubricated Propeller ShaftsShaft and Pod Seals are not perfect• Pollution risk

Seal must leak to lubricate its sealing lip Oil pollution from leaking shaft or pod seal

• Rope and fishing line damage seals Escalating detection and enforcement

• MARPOL Annex I / Satellite tracking• Criminal fines / jail terms• US EPA Vessel General Permit• Polar Code

Increased expectation of corporate responsibility

• Damage to corporate brand and image

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DNV Report -Potential for High Oil Leakage Rates in Ice Operation

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• Prepared for Norwegian Maritime Directoratefor consideration of Development of a Mandatory Code for Ships Operating in Polar Waters

• Discharges from shipping during regular operation in polar areas

• Presented at IMO DE 54 (Aug. 2010)As a potentially relative large source of operational oil discharge, however still not effectively regulated and of unknown exact magnitude, stern tube leakage should be addressed as a particular environmental aspect in the polar environment as well as in other areas. Of particular importance under ice operation is the potential for especially high leakage rates, and the proximity to ice with regards to deposition of oil.

Accidental Oil Leakage

Lloyd’s Register reports… “Defect statistics over the last 20 years indicate that the aft stern bush represents 10% of shaft line failures, with the forward stern bush representing 4% of total failures. Interestingly, the aft stern gland (seal) and forward stern gland (seal) represent 43% and 24% of failures respectively.”

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Smith, Andrew, Lloyd’s Register Global Technology Leader-Engineering Systems ., “Shaft Alignment Problems Analyzed,” Marine Engineers Review April 2009, pp. 16

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Accidental Oil Leakage

• Typical causes of increased oil leakage from stern tube seal damage: Fishing nets or rope caught in the propeller Propeller shaft misalignment or bent shafts Aged or worn lip seals Propeller contact

with ice or striking bottom

Trading in US Waters?

• 2013 Vessel General Permit (VGP) regulates discharges from commercial vessels in ‘US waters’ effective Dec. 19, 2013

• Section 2.2.9: All vessels must use an EAL “Environmentally acceptable lubricant” in all oil to sea interfaces, unless technically infeasible

• EPA recommends that all new build vessel operators endeavor to use seawater-based systems for their stern tube lubrication to eliminate the discharge of oil from these interfaces to the aquatic environment.

9 http://www.epa.gov/npdes/vessels

New Polar Code

• Development of a Polar Code for ships operating in polar waters

• Polar waters will be “zero discharge” areas under MARPOL Annexes 1 and 2 (oil and noxious liquids).

• The Code states: “Any discharge into the sea of oil or oily mixtures from any ship shall be prohibited.”

• Polar Code enters into force:

January 1, 2017

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Shaft Air SealsAre they the answer?

• A major seal manufacturer states the following related to air seals on their website:

However, since it is not possible to rule out circumstances in which there could be a leakage, EALs must be used on this type of seal as well.

• Depending on seal manufacturer and EAL, the EAL will need to be replaced either at 2.5 or 5 year drydocking (aggressive nature of the EAL on seals)

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http://www.simplexturbulo.com/2013/07/12/vessel-general-permit-latest-news/

Typical Piping of Air Seal

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Air control unitAir source

(Control Air)

L.O. tank unit

Floatswitch

Stern tube

Stern tubeL.O. pump unit

Filter

Pump

Draincollection unit

Flow meter

AirOil

Slight amount of air is leaked from here.

Aft seal

Cooler

Needle valve

EAL’s – Still considered a pollutant Oil-based EAL’s are still considered a pollutant under the

Oil Pollution Act of 1990 (OPA ‘90) and US Clean Water Act (if there is a sheen)

Any discharges of oil-based EAL’s still require reporting of the discharge to the U.S. Coast Guard, as well as having clean-up and remediation costs.

Even though biodegradable lubricants may be deemed non-toxic by OECD testing, their presence on the water surface is a threat to seabirds

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Stern Tube Lubricants

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Seawater Lubrication• Seawater as a lubricant dates back to

earliest days of shaft driven propellers

• Today’s seawater lubricated propeller shaft lines quite different than those of 1940’s

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Seawater Lubricated Propeller Shaft Bearing System

Piping for Seawater Lubricated Propeller Shaft Bearing System

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NO AFT SEAL!

New Lloyd’s Register Rules for Water Lubricated

Propeller Shaft Bearings

• New SCM (Screwshaft Conditioning Monitoring) Notation For water lubricated propeller shaft bearings Effective Jan. 2013

• If vessel is compliant, no shaft withdrawal until 18 years from newbuild

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New Bureau Veritas Rules for Water Lubricated

Propeller Shaft Bearings• Revised MON-SHAFT Notation

For water (and oil) lubricated propeller shaft bearings

Effective Jan. 1, 2014

• The tailshaft need not be withdrawn provided that all condition monitoring data are found to be within the permissible limits and remaining surveys are complied with

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Who Uses Seawater Lubricated Propeller Shaft Bearings?

Over 600 commercial ships including…• Flinter Group (Netherlands) – 24 dry cargo ships• Carisbrooke Shipping (U.K.) - 8 dry cargo ships• CSL (Canada) - 9 bulk carriers • COSCO (China) - 12 bulk carriers, 3 car carriers, 20 On order• BC Ferries (Canada) - 10 ferries• Staten Island Ferries (U.S.A) - 3 ferries• ConocoPhillips (U.S.A.)- 5 oil tankers • Disney Cruise Lines (U.S.A.) – 4 cruise ships

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Carnival Corp. (U.S.A.) – 17 Cruise ships (108,000 to 115,000grt) equipped with seawater lubricated propeller shaft lines. Two more on order.

Grand Princess uses seawater lubricated prop shaft linessince 1998

Long Predictable Bearing Wear Life

Operational & Performance Benefits

• Zero Pollution Risk Eliminate oil from the stern tube

• Controlled Bearing Environment Water Quality Package Allows for SCM & T-MON Notation– No shaft

withdrawal for 18 years with monitoring

• Technical equivalence Viable alternative to oil lubricated white metal

propeller shaft bearings

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Operational & Performance Benefits

• Reduced Operating Costs• No Aft seal to maintain as there is no Aft seal

(water lubricated FWD seal only)

• Eliminate oil or EAL’s from the stern tube no purchase of oil or EAL’s no storage of oil no sampling of oil no disposal of oil no labour required to top up header tanks

• Maintenance of seawater lubricated propeller shaft bearing system is very low

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The Future

• Environmental compliance for a ship owner is a constantly moving line and it is not going backwards.

• Seawater is the only system that guarantees compliance and has ZERO impact on environment.

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