Marine Construction
Since 1919, Brennan has been a trusted leader in marine construction by assessing, installing, and repairing structures above, alongside, and below the waterline. Our experienced topside crews and ADCI-certified divers bring the skill, precision, and safety focus needed to complete every project on time and within budget. From multi-million-dollar capital developments to short-duration dive inspections, Brennan delivers the same level of professionalism and quality. With a strong bonding capacity, proven expertise, and over a century of experience, we provide reliable, high-performing marine construction solutions for clients across North America.
By partnering early in design-build and Construction Manager/General Contractor (CMGC) projects, we identify potential challenges and collaborate with all stakeholders on design and constructability.
- Reduces cost escalation
- Enhances project coordination
- Results in fewer delays
- Improves communication
- Lowers risk for all teammates
- Provides more accurate cost predictions
Harbor Services
When Brennan manages your harbor operations, you gain real-time visibility into barge locations, arrivals, and departures by maximizing efficiency and minimizing downtime. All our vessels are U.S. Coast Guard Subchapter M–compliant, and we’re proud members of the American Waterway Operators (AWO) Responsible Carrier Program (RCP). With Brennan, you can count on safe, professional, and transparent harbor management every step of the way, for every type of operation.
- 24-hour dispatch
- AWO RCP-compliant vessels
- Barge cleaning
- Real-time tracking
- Short-haul towing
- Shipyard services
- Switching and fleeting services
Maritime Security Barriers
Brennan is the exclusive supplier of Harbor Offshore Barriers™, the global standard for maritime security, and a trusted provider for the U.S. Navy’s floating protection program. Our fixed and floating barrier systems safeguard critical infrastructure against fast inshore attack crafts, multiple-boat assaults, explosive devices, and underwater intrusions—offering proven defense before, during, and after impact.
- Airports
- Bridges
- Chemical plants
- Dams and hydropower plants
- Desalination plants
- Shipyards
- Liquefied natural gas (LNG), oil and transport facilities
- Military facilities and installations
- Nuclear power plants
Underwater Inspections and Survey
When a project’s greatest risks lie beneath the surface, Brennan delivers clarity. Our licensed hydrographers use advanced survey technologies to create precise, detailed models of underwater environments helping clients identify challenges, reduce risk, and plan with confidence. Our underwater investigation capabilities surpass other contractors, and include:
- Dive inspections
- Light detection and ranging (LiDAR)
- Multi- beam and single-beam bathymetric surveys
- Photogrammetry
- Remotely operated vehicles (ROVs)
- Side-scan sonar
- Underwater acoustic imaging
- Voyis Visual Simultaneous Localization and Mapping (VSLAM)
Dive Inspections
With 100+ ADCI-certified divers on staff, we conduct a thorough assessment of your structure, identify areas of interest, and produce a detailed report that can be used for further analysis.
- Concrete assessment
- Core sampling
- Historical artifact assessment
- Intakes and outfalls
- Micro-dredging and clearing
- Radiological contaminated diving
Fossil Fuels
Brennan provides a full range of services to maintain and enhance the performance of critical industrial infrastructure. From the precise cleaning of cooling towers and circulating water systems to pipeline inspection and repair, our experienced team delivers safe, efficient solutions tailored to the demanding needs of facilities that rely on fossil fuels.
Areas of Expertise
- Barge terminals
- Port facilities
- Cooling systems
- Traveling water screens
- Pipeline installation, repair, and replacement
- Coal ash ponds
- Manufactured gas plant (MGP) remediation
- Environmental remediation
Hydroelectric Dams
Maintaining reliable, efficient hydroelectric operations requires expertise both above and below the waterline and Brennan delivers exactly that. Our team specializes in hydroelectric dam construction, repair, and rehabilitation, from replacing bulkheads and repairing submerged trash racks to building entirely new structures. Backed by experienced welders, ADCI-certified commercial divers, and specialized marine equipment, we provide safe, high-quality solutions that keep your hydroelectric facilities generating clean, dependable power for years to come.
- Anchoring
- Cofferdams
- Fish passage and protection
- Gates, actuator, and mechanicals
- Intakes and trash racks
- Major rehabilitation
- Penstocks
- Powerhouse structures
- Spillways
- Tailraces
Nuclear Generation Facilities
In the highly specialized world of nuclear power, safety and precision are non-negotiable. Brennan provides a comprehensive range of underwater services tailored to the unique demands of nuclear generation facilities. Our ADCI-certified divers are trained to perform VT-1 and VT-3 visual examinations, execute complex repairs on reactor components, and work safely in challenging underwater environments. We support the inspection, maintenance, and repair of condensate storage tanks, fuel transfer systems, valves, and other critical infrastructure along with expert underwater welding and coating applications. Backed by strict compliance standards and a culture of safety, Brennan ensures your nuclear facility operates at peak performance, maintaining the reliability and longevity of this essential energy source.
- Coating application
- Cooling pond dredging
- Condensate storage tanks
- Fish protection
- Fuel transfer systems
- Intakes and outfalls
- Reactor components
- Traveling water screens
- Valves and seals
- Visual examinations (VT-1 and VT-3)
- 10 Code of Federal Regulations (CFR) 50 Nuclear Quality Assurance (NQA1 Program)
- Maritime security barriers
Transmission & Distribution
Brennan is the trusted marine contractor for water-based transmission and distribution projects across the nation. We specialize in deep foundations, shoring systems, and sheet-pile structures in challenging environments such as rivers, marshes, and wetlands. Our amphibious equipment gives us a unique edge allowing us to access remote sites and complete complex work with minimal environmental impact. Collaboration is at the heart of every project. We work closely with clients, engineers, and contractors to solve complex, water-based grid-hardening challenges. Our experienced crews are skilled in low-clearance operations, efficiently completing work beneath railroad bridges and power lines using a versatile array of specialized tools and equipment.
- Geotechnical support
- Marsh and wetland site access
- River crossings
- Scour remediation
- Transmission tower foundations
- Tower removal and replacement
- Utility pole shoring
Environmental Restoration
At Brennan, we are committed to restoring and protecting our natural waterways. We work closely with clients and their engineers to design and execute effective solutions for complex restoration and remediation projects. Our turnkey services include environmental dredging, dewatering, and water treatment, each tailored to the specific needs of the site. With precision, innovation, and environmental stewardship at the core of every project, Brennan delivers lasting results for cleaner, healthier ecosystems.
- Capping
- Coal ash ponds
- Cooling ponds
- Habitat restoration
- Manufactured gas plants (MGP)
- Marshes and wetlands
- Water treatment
At Brennan, we provide quality above- and below-water marine construction, barge transportation, and environmental remediation services to the energy industry.
Connect with Brennan using the form below
© 2022 J.F. Brennan Company, Inc.
Main Office Location
818 Bainbridge Street
La Crosse, WI 54603
Phone: 608/784-7173
Fax: 608/785-2090
Payroll Fax: 608/881-6519
24 Hour Dispatch
24/7 Service
Call 800-658-9027
