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

General Plan-3.jpg

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.

Structural Engineering Case Study – Finite Element Analysis of Rudder Horn

Stress Contour GIF Full.gif

Herbert Engineering is a capable provider of structural engineering services for projects both large and small.  A great example of one of our smaller structural engineering projects was a forensic investigation into a series of fractures in the rudder horn region of a class of containerships.  

Using a solid-element finite element model with “contact” to correctly simulate the interaction between rudder stock and bearings, Herbert Engineering was able to identify the fatigue hotspots corresponding to the known fracture origination points and provide the ship owner with clear guidance on how to address this issue.

March 2018 NSMV Roundup


On March 23, the FY2018 U.S. federal budget was passed and included $300 million for planning, designing and building the National Security Multi-mission vessel (NSMV), designed by Herbert Engineering Corp. for MARAD to replace the existing and ageing cadet training ships of the State Maritime Academies.

Articles in GCaptain and Maritime Executive were published on the day.

Marine Link previously had a detailed feature about the design of the vessel - Designing the New National Security Multi-Mission Vessel that was published in August 2017, and followed that up with an article in January 2018 - Domestic Maritime Training: In Extremis.

NSMV FEA 1.jpg

A short presentation about the design was given to the NorCal section of SNAME in February (with webinar) and video visualisations of the design were produced for MARAD. Full length video below and summary version here.

NSMV Design Presentation at SNAME NorCal

NSMV Model V12_7_6_Rudder And Propeller Detailed View.jpg

HEC President Spencer Schilling gave a presentation on NSMV Design on Feb 21, 2018 from 6:00 PM to 9:00 PM (PST) during the Northern California Section of SNAME at Pasta Pelican restaurant in Alameda, California.

State Maritime Academies vessels are aging. Herbert Engineering has been working with the US Maritime Administration for several years to design and build new training ships with modern propulsion systems and improved training facilities. It is hoped that these vessels will be used for national response to humanitarian and environmental disasters just as they have done in the past. The NSMV - which stands for National Security Multi-Mission Vessel will be able to both respond to sea emergencies and educate future naval officers at the same time.

Above propeller image rendered by Dale Pederson.

Webinar here and presentation can be downloaded here.