Scrubber For Existing Vessels - Retrofit Solutions

Jesse Senkel from Herbert Engineering’s Houston office took part in a panel discussion about “Scrubber for existing vessels – Retrofit solutions”  at the Americas Sulphur Cap 2020 Conference, where he talked about Herbert Engineering’s experience in designing scrubber systems for a variety of different ship types. The discussion was very interesting, touching upon the different aspects of choosing between scrubbers and compliant fuel. If you missed this opportunity, you can meet Jesse at CMA between April 2nd and 4th in Stamford, CT.

Wreck Removal of SE Panthea

HEC Presentation at Salvage & Wreck Asia 2018

HEC Director Rob Tagg will present “Wreck Removal of the SE Panthea” on September 26th at 11:20 am during the Salvage & Wreck Asia 2018 Conference in Singapore. The innovative technical lessons learned will be revealed through a description of the wreck removal based on the SE Panthea’s unique conditions. Matt Zheng of Zhengli Offshore Salvage and Engineering will join him in addressing casualty operation and management for the wreck removal.


The bulk carrier SE Panthea was beached by typhoon Hatto on August 23, 2017 on a small unmanned island in the Pearl River Estuary between Macau and Hong Kong. Initially all pumpable bunkers were removed, followed by the cargo, hatch covers, tween decks, cranes and anchors & chain. The conditions of the hard aground position from beaching at high tide and the typhoon storm surge informed our strategy to separate and remove the wreck by in 9 blocks by 1200 ton floating crane.

After removing the accommodation and engine room sections, we formed a new plan to remove the forebody refloating as a single section. We used a combination of dewatering the intact spaces and pressurizing damaged some double bottom and wing tank spaces, along with additional bow lift from the floating crane.

The forebody was successfully refloated at high tide on January 29th 2018 and was towed to a nearby submersible heavy lift barge for scrapyard transport.

Hope to see you there on the 26th!
Please find links to the conference at:


Services for Ports & Terminals

Harbor Operability.jpg

In the past 15-20 years, the unprecedented growth in the size of container ships, gas carriers and bulk carriers has put significant strain on port facilities and waterways due to the significant increase in dredging and number of offshore wind farms. HEC has worked on numerous projects to solve navigation challenges and reduce the environmental footprint for ship owners and ports.

Harbor Operability Analysis


Recently, HEC combined 3D ship modeling with a 3D bathymetric model of the local underwater topology of an existing berth to determine if a ship owner’s existing and unbuilt ships would be able to be accommodated. This study cross referenced loading conditions and tidal conditions to determine berthing feasibility. Mooring loads and container crane outreach were also analyzed. Find out more here.

Estimating Emissions

HEC specializes in evaluating all types of hull forms, propulsion plant and fuel options for new ships, and getting existing ships to comply with international and local emission regulations. We have developed a  proprietary tool that evaluates propulsion options, fuel types and boil off gas/reliquefaction capacity for newbuild LNG carriers.

The data, methodology and tools derived from these projects have formed the basis for a number of emissions calculators. One application of a Carbon Footprint Study for the Port of Seattle may be found here.

Another recent application conducted for a US oil major’s strategic research team determined fuel consumption and emissions from bulk shipping considering different import/export terminals, cargo quantity, vessel size, engine and fuel types, exhaust treatment methods and emissions regulations.

A third application has been to supply the Institute for Water Resources of the US Army Corp of Engineers with fuel consumption estimates for a wide range of oceangoing vessels.

Wake Modelling

The Institute for Water Resources (IWR) of the US Army Corp of Engineers evaluates waterway improvements proposed for coastal harbor projects using an advanced suite of techno-economic tools and models.

HEC has provided sample hull lines for a wide range of ship types and sizes and a wake model to the IWR for use in their evaluations.

Other Work

HEC has also carried out other work for ports:

  • Navigational Risk studies - see projects here and case study
  • Terminal studies - such as one for a gravity base LNG receiving terminal
  • A study for OCIMF looking into crane loads associated with hose handling at offshore terminals
  • Cold ironing trials at the Port of Oakland on a containership


Clean Jacksonville LNG Bunker Barge

HEC/GTT Original Design

HEC/GTT Original Design

It is always interesting to follow the development of our designs through to build and eventual operation. In this case this bunker barge began life in 2013 as a concept design project for GTT.

The GTT Demonstrator Mark III LNG bunker barge was designed to demonstrate the use of the GTT Mark III membrane containment system in an unmanned LNG Bunker barge.  This design demonstrated the feasibility of how the GTT Mark III containment could be used on a small scale, in a compact barge arrangement and meet all the handling requirements in a safe, reliable and cost effective manner.  

It was based on general requirements at the time for the markets for LNG bunkering in near coastal and inland markets.  The capacity is based generally on what these markets may require for refueling multiple smaller vessels (tugs, OSV’s, etc.) and larger ships that serve shorter (Jones Act) voyages.  The barge could operate as a mobile refueling resource (taking the fuel to the vessels) or moored/tied up to serve as a refueling station. 

Features of this concept can be scaled up to other services and vessel types as required by the trade being pursued.

One of the most important features addressed with this Demonstrator LNG bunker barge design is the manner in which boil off gas from the Mark III atmospheric tank is handled to provide safe operation over a market viable voyage profile.  All key regulatory requirements for design and operation were considered, including loading, discharge, transit, and emergency situations.

LNG Bunker Barge.jpg

HEC worked on structure, hull lines, design of the cargo handling system considering initial tank gassing up and cool down, LNG loading, idle mode, LNG offloading, tank warm up and inerting and boil off gas management. Also considered were hazardous area zones, protective location requirements for the LNG tanks, emergency shut down system, fire fighting, docking arrangement, fendering, ballast for trim and heel control, load balance and generating capacity.

ABS granted approval in principle in March 2014, followed by DNVGL in June 2014.

In February 2015, GTT North America received an order for the barge from Wespac Midstream LLC and Clean Marine Energy LLC to be built at Conrad Orange Shipyard, Inc. to serve Tote's new LNG powered container ships. At this point, GTT had added a GTT Reach4 LNG bunker mast as seen below.

Credit: GTT

Credit: GTT

Conrad Industries and their design contractor Bristol Harbor Group proceeded to develop the design, including large service and work spaces for equipment operators and a larger hose handling crane.

Jax LNG, who will be the operator of the barge, received their license to conduct ship to ship LNG bunkering operations in August 2017, and it is understood that the barge was delivered at the end of 2017, to commence bunkering in early 2018.

Credit:  LNG World News

Here are some details of our other LNG projects.

600 FEU Reefer Design

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Container ship and reefer design have featured prominently in the history of HEC. We were heavily involved in the development of the open hatch container ship concept and the accompanying US and IMO regulations. HEC was also instrumental in the creation of the modern cross lashing securing system and the lashing bridge concept. Long-time customers include Matson, Sea-Land, Horizon, and APL where we participated in the design of the first post-panamax container ship.

Recently, a customer asked us to provide a design for a 600 FEU fully containerized reefer vessel. The worldwide reefer fleet has an average age of around 25 years, and while under pressure from conventional container ships fitted with reefer plugs, the segment still provides shorter transits and direct routings.

The ship is designed to carry 600 forty foot, 28 tonnes, reefer containers with a deadweight of around 19000 tonnes. Service speed of 20 knots is achieved with installed power of only 13,625 kW. Attained EEDI meets phase II requirements.

General Plan-3.jpg

The design was provided with a range of options:

A - Gantry cranes rather than jib cranes

B - Vertical Bow for improved wave resistance

C - Rudder & Propeller Hub Efficiency devices

D - Underdeck water cooled or refrigerated hold

E - Dual fuel engine and LNG Ready

F - Exhaust Gas scrubber

Other capacities and configurations are available and a datasheet is available on request.