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A Look at the Tier 4 World

If you want to run in circles, go to 40 CFR to read and read and read about the government’s EPA regulations on reducing the pollution in the exhaust emissions of marine diesel engines. Otherwise, let’s try to understand what is important to us as surveyors and appraisers of marine equipment and to marine asset lenders.

The bottom line is that all domestically built vessels with an engine over 800 HP (600kW-804 HP, as of October 1, 2017) must have Tier 4 compliant engines. There is a new exception to this which I’ll come back to later.

As a loophole and marketing tool, some shipyards laid speculation keels prior to the Tier 4 activation date, making it possible for an owner to build new vessels after October 1, 2017 with machinery based on the EPA regulations in effect at the time of the official keel laying. This seemed to have worked for the past few years, but the speculation keels are running out and, in some cases, have proven to be insufficient for the needs of the weight and size of Tier 4 engines.

Why do Tier 4 engines and the boats they go on cost so much?

Tier 4 engines are bigger. Involved are after treatment systems, larger heat exchangers, and changes to filter systems, other engine items, and turbochargers.

Tier 4 engines run hotter. Up front that means different wiring and extensive shielding. Lobster boats with larger engines were having problems with the extra heat from the engines plus heat from the Selective Catalytic Reduction (SCR) units was heating the lobster holding tank water and therefore starting to cook the catch. Companies like Fernstrum have come up with retrofit cooling plans for boats that have upgraded to Tier 4 engines.

Tier 4 engines have sophisticated electronics. The engine control systems located in the Engine Control Unit (ECU) monitors and manages numerous conditions in order to maintain combustion efficiency. All of the changes in load, torque and required horsepower during operation need to be managed.

Tier 4 engines need additional gauging and indicators. Besides a sophisticated ECU, there is a need for a DEF indicator, DEF level gauge, regeneration indicator, regeneration disabled indicator, and increased need for exhaust gas temperature and high temperature alarm.

Tier 4 engines produce less functional horsepower. Tier 4 engines don’t produce as much functional horsepower as non-Tier 4 engines so a larger horsepower engine is needed. All of the add-ons reduced effective shaft horsepower.

Finding enough usable space in a vessel’s hull for larger, heavier engines plus the emission abatement equipment means that a hull must be larger and possibly stronger to handle Tier 4 engines of the same effective horsepower of pre-Tier 4 engines. Remember, stability is a factor in the design of a hull, so things can’t always be placed at the most convenient and inexpensive place within a hull.

Among the add-ons are three major technologies used for exhaust cleansing:

  • Selective Catalytic Reduction (SCR): In this system, the exhaust gasses are combined with ammonia in the form of Diesel Exhaust/Emission Fluid (DEF), a mixture of about 1/3rd urea and 2/3rds water. The exhaust gas mixes with the DEF and passes over a catalyst, cleaning the exhaust and mainly sending water and nitrogen into that atmosphere. There are complaints from owners and operators that getting a needed supply of DEF when and where a vessel happens to be can be a logistical challenge. However, this is the most used system for commercial marine vessels.
  • Diesel Particulate Filter (DPF): This is a mechanical filter that with the aid of a catalyst traps soot. The soot in the filter is periodically cleaned by incineration or a puff jet into a dust/soot box.
  • Exhaust Gas Recirculation (EGR): This system takes some of the exhaust gas and re-routes it back into the combustion chambers reducing NOx. EGR must be used with a DEF to meet current standards.

Earlier I mentioned a new exemption to the EPA Tier 4 regulations.

There are no Tier 4 engines manufactured for use in commercial high-speed planing hulls such as those used by pilot association, some patrol/law enforcement craft and in fishing, such as lobster boats. Current engines are too bulky to fit and too heavy to allow these boats to reach the desired speed performance. The EPA has given these designs a temporary pass until suitable compliant engines can be produced.

A second action by the EPA is changing EPA standards on exhaust emissions to match IMO standards so U.S. vessels will be built in sync with the rest of the marine world’s regulations issued by the IMO.

But it’s not over.

European Stage V regulations and IMO changes may make it necessary for the EPA to come up with Tier V. The European Stage V for non-road engines and inland waterways came into effect in 2019 and 2020. But if the EPA did go to higher standards it would probably do it in a step-by-step process – starting with on-road and off-road vehicles and engines sizes. The original EPA Tier process started in 2008. As engineering and processes in this field have gained experience, the implementation should not take the 12 years the original standards took.

There are some workarounds to Tier 4 engine requirements, particularly for those in need of lower horsepower engines. Instead of one 1400 HP engine, some owners will go for two 750 HP engines to stay under the 804 HP mandate. All engines under 804 HP will stay under Tier 3 regulations.

Another out is a hybrid design. Some vessels, including harbor use tugs, only need their high horsepower rating for short periods. There is no reason to pay for and feed that size engine(s) when most of the time it is not being fully used. By having an electric hybrid, the battery bank and electric motor can instantly provide the extra horsepower and torque above the normal needs, requiring lower base horsepower installations.

We as marine surveyors and appraisers, marine lenders, and of course vessel owners, will be living with the complexity and cost of these engines for quite a while. We need to understand why they are more complex and more expensive. We also need to be aware that most of the world is moving ahead with higher ecological standards. All international engine companies must build to the highest standards, and any vessels being used in any kind of international service will be asked by international customers/charterers, and/or the local authorities, to be compliant with the standards in force. There will have to be compliance to be competitive.

Norman Laskay

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Matt McDaniel DLS Marine Survey and Appraisal

Matt McDaniel

Hull & Machinery Surveyor

Areas of Expertise:

  • Hull and Machinery
  • Damage Assessment and Repairs
  • Condition
  • Inspections
  • Project Management

Memberships / Professional Certification:



Matt began marine surveying in 2014 and has experience with damage causation, reviewing transit plans, new construction, cargo transfers, salvage operations, on/off charters, and general condition surveys. He joined the Hull & Machinery department at DLS in 2019.
Charles Sterling - DLS - UAV Supervisor | Digital Inspection Manager

Charles Sterling

UAV Supervisor | Digital Inspection Manager

Areas of Expertise:

  • Uncrewed Aerial Vehicles & ROV’s
  • Digital Inspections
  • Computer Technology

Professional Certifications:

  • AS, Computer Information Systems
  • BS, Information Technology
  • FLIR Infrared Training Institute

Certified Specialist in Caterpillar diesel engines to include:

  • CFR Part 107
  • Level 1 sUAS Thermographer
  • Microsoft Certified System Engineer


Charles joined the firm in 2024, after managing an enterprise drone service provider based in New Orleans. He also teaches basic and advanced UAV class at Delgado Community College. Charles has extensive experience planning, flying complex missions in the Industrial, Chemical and Oil & Gas industries.

Ave P. Boudreaux

Marine Surveyor

Areas of Expertise:

  • Hull and Machinery
  • Project Management Supervisor (QC) – overseen numerous construction and delivery schedules for vessels
  • Extensive knowledge of U.S. Coast Guard and ABS rules and regulations for vessel construction and repair


  • Rolls-Royce Z-Drive Failure Analysis Seminar
  • Flex-Core and Aluminum Welding Course
  • Extensive training in engine, gear, and shaft alignment
  • Extensive training in vessel repair and new construction

Memberships / Professional Certification:



Mr. Boudreaux has 15 years experience with offshore supply vessels, crewboats, and anchor handling tugs. During this time, he served 8 years in vessel repair and new construction, 3 years in vessel operation and logistics, and 4 years as a vessel port captain.

Mr. Boudreaux served over 3 years as a marine surveyor performing numerous types of surveys in the marine industry prior to joining DLS.

Norm Laskay - DLS Marine Valuation

Norman F. Laskay

Of Counsel

Mr. Laskay joined Stickney, Dufour & Associates, Inc. in 1988 as a partner. He is now of Counsel. He became a Marine Surveyor in 1974, having gained prior experience in steamship agency, bulk cargo handling and vessel operations. He has been involved in many aspects of marine surveying including hull, machinery and cargo, both inland and ocean. Since becoming an Accredited Senior Appraiser of commercial marine equipment, he has been active with the American Society of Appraisers’ International Machinery and Technical Specialties Committee. He has written a comprehensive exam for the Commercial Marine Appraisal specialty and has written a 30-hour course for the American Society of Appraisers on appraising commercial marine vessels and yachts and is the lead instructor.

Areas of Expertise:

  • Commercial Marine Appraisal
  • Hull Damage and Repair
  • Cargo Loading, Securing and Trip in Tow Preparation


  • Maine Maritime Academy Graduate
    B.S. in Marine Transportation
  • Continuing education credits in Law, Appraisal, Marine Survey, and Diesel Repair.

Professional Certification/Memberships:

  • NAMS Regional Board of Directors Member 1989-1994
  • American Society of Appraisers – Chapter Treasurer 1991-1994
  • American Society of Appraisers – Chapter President 1994-1995
  • Mark Twain Club (Charter Member)
  • Machinery and Technical Specialties International Committee 1995-Present


  • The Journal of the International Machinery & Technical Specialties Committee of the American Society of Appraisers “TUGBOAT DESIGN 101” Vol 13 No. 2 Fall 1996
  • The Journal of the International Machinery & Technical Specialties Committee of the American Society of Appraisers “KEEPING AN EYE ON YOUR MARINE ASSET” Vol 13 No. 3 Winter 1996
  • Marine Money, The Ship Finance Publication of Record “ASSET BASED APPRAISAL:, Vol. 21, No. 3, May/June 2006 Wrote the chapter on Marine Asset Appraisal for the American Society of Appraisers text book: “VALUING MACHINERY AND EQUIPMENT: THE FUNDAMENTALS OF APPRAISING MACHINERY AND TECHNICAL ASSETS” Second Edition. In 2008, revised the chapter for the future Third Edition and wrote an accompanying Work Book section.



Harry Ward President DLS Marine

Harry Ward


Harry Ward is the President of Dufour, Laskay & Strouse, Inc. Harry is a US Navy veteran and has spent much of the past decade in the maritime industry in sales, finance and general management. He has extensive experience in asset and business valuation and is working to maintain DLS leadership in marine appraisal and survey for another 50 years. Harry is a graduate of the US Naval Academy and served as a helicopter pilot and survival instructor through multiple tours of duty. He has an MBA from San Diego State University.

Areas of Expertise:

  • Fleet and Vessel Appraisals
  • Marine Business Valuation
  • Transaction Support – Due Diligence
  • Transaction Support – Marine M&A Advisory
  • Digital Inspection – Marine and Offshore Wind


  • U. S. Naval Academy, Annapolis, MD – 1991, Bachelor of Science
  • San Diego State University, San Diego, CA – 1999, MBA with emphasis in Finance

Licenses and Professional Associations

  • FINRA Licenses, Series 63 and 79 (Investment Banking)
  • American Society of Appraisers, AM
  • Certified Exit Planning Advisor, CEPA (Business value assessment and strategy development