Author: Shawn Henderson, P.E.
#NDTLevelIII #WeldInspection #ProfessionalEngineer #StructuralAnalysis #Refit #TexasCommercialDiving #FisherTechnicalSolutions

In conjunction with strategic partners we are able to fully manage and execute scans and inspections both above the waterline and subsea in order to save time with field work. This includes structural inspection beneath the waterline by a Professional Engineer and management of NDT methods including visual inspection, magnetic particle inspection, ultrasonic inspection and dye penetrant inspection. Our team incorporates the use of specialized SONAR, photographic cameras with clear water boxes, laser scanners and Unmanned Aerial Systems (UAS) to access inherently dangerous locations to clarify existing condition, damage, corrosion and the integrity of cathodic protection systems.

An experienced Professional Engineer onsite can interpret data and quantify locations and the extent of damage. The data from scans and inspections can be used cumulatively. Henderson & Associates, PLLC integrates professional engineering with technically managing skilled trades from sometimes complex sets of requirements.

Contact me at shawn@ocean-engineers.com, (904) 437-4535 for more information or to set up a consultation.

Author: Shawn Henderson, P.E.
​Underwater tactile inspection in turbid water by an experienced Professional Engineer adds more resolution to SONAR scanning.
 
#UHServicesGroup #LeviathanOffshore #3DSONAR #ProfessionalEngineer #CommercialDiving
We recently inspected structural damage 110 feet beneath the waterline on a dam in turbid water. Seasoned project managers were responsible for assembling a qualified team to a remote location within a limited time. Professional commercial divers rigged equipment across to the site and then down to depth and prepared the confined space area for inspection in zero visibility. The location and extent of the damage was assessed by a Professional Engineer/commercial diver conducting tactile inspection and the use of a post-processed point cloud created from multiple scans of a 3D multibeam SONAR (BlueView 5000) launched on a tripod.

LIGHT IN TURBID WATER
The scattering of visible light in turbid water makes visual inspections impractical. Visible light waves that penetrate ocean water are absorbed or scatter. Blue light (λ 475 nm) penetrates the deepest in clear ocean water. Clear water boxes can aid with inspection techniques that use light.
 
SOUND IN TURBID WATER
A SONAR wave frequency pf 3.0 MHz (λ 500 µm) has a wave length more than 1000x longer than visible blue light minimizing wave scattering and allowing clearer imaging in turbid water. Rougher surfaces (damage) scatter diffusely more acoustic energy. Resolution is dependent on many variables including: range; frequency; noise; target geometry; reflectivity; onscreen pixels; and sampling characteristics.
 
TACTILE INSPECTION (Professional Engineer) IN TURBID WATER
Tactile inspection can be performed by a Professional Engineer to determine gross damage and boundary conditions. From many years of experience a flaw resolution of ¼” is practical over a complete area in zero visibility, although tactile inspection cannot determine flatness across an expanse.

CONCLUSION  
An experienced Professional Engineer onsite can interpret data and quantify locations and the extent of damage. The data from both the 3D SONAR scans and tactile inspection can be used cumulatively. Henderson & Associates, PLLC integrates professional engineering with technically managing skilled trades from sometimes complex sets of requirements.
 
Please contact us for more information or to set up a consultation.
Shawn Henderson, P.E.
Shawn@Ocean-Engineers.com 

Shawn Henderson, P.E.
A couple years ago, my wife and I planned a summer vacation for our three kids (ages 4, 2 and 1) to visit my 72 year old father and step-mother in Washington state. We planned to fly from Miami, Florida to Seattle, Washington and then drive over the mountains into central Washington state. The schedule shifted at the last minute. We left Miami with the clothes on our back as our home was tented for bugs, and together my wife and I entertained two kids on an airplane for hours while nursing the third for an ear squeeze. When we finally reached my dad’s house, the kids’ guest room was full of antique toys that were not supposed to be played with, which of course wasn’t a realistic expectation. Even with these unexpected challenges, we had a good vacation and everyone parted ways happy. This had a lot to do with an initial well-crafted plan and adaptable good-intentioned adults.

Project management of diving operations has a lot in common with our family vacation to Washington state. Managing divers, engineering and a client can be tricky. It takes strong willed and innovative people to consistently perform well underwater (rigging, welding, NDE, mechanics) and quickly develop solutions in a challenging environment. These same personal characteristics can also lead to conflict, so a well-crafted, pre-approved dive plan is necessary before a project begins. Using dynamic risk analysis and consistent client communication, effective managers will put in place the right equipment, the right supervisors, professional divers, and a work scope that leads to a favorable outcome from the outset.

We recently assisted a diving contractor, TCD (Texas Commercial Diving), with project management on an ABS non-destructive examination of critical structural areas on a semi-submersible drilling rig. The critical structural areas focused on the transition of the platform columns to pontoons. Texas Commercial Diving spent several months properly certifying divers to conduct VT, MT and UT examination (visual, magnetic particle and ultrasonic). We created professional engineering drawings for the necessary cofferdam and an umbilical management plan for diving in proximity to the active azimuthing thrusters. The project was completed on time, under budget and everyone went home happy.

Like our family vacation to Washington state, the TCD project presented our team with plenty of challenges. However, we spent adequate time on the front end crafting our plan and approached the common goal as a team with levelheaded commitment.

Based in Jacksonville, Florida, Henderson & Associates, PLLC is an ocean engineering services firm specializing in structural refit beneath the waterline including: Professional engineering drawings; dive plans; rigging plans; and project management of welding and diving operations. Shawn Henderson, P.E. began his career as a U.S. Navy deep sea diver and welder and has spent the last 20+ years working with commercial divers. He acts as a professional engineer/diver. Contact me at shawn@ocean-engineers.com for more information or to set up a consultation.

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​Author: Shawn Henderson, P.E.
Henderson & Associates provides project management and Professional Engineering drawings for Classed ship refit. We combine years of practical at-sea experience with formal training in ocean engineering. Henderson & Associates has pioneered innovative techniques for conducting refit of components and hull structure beneath the waterline. Professional Engineers are registered and licensed through the Florida Board of Professional Engineers as well as maintain active memberships with specific engineering societies (the Society of Naval Architects and Marine Engineers, the American Welding Society, the American Society for Non-Destructive Testing).

Project: ABS aluminum hull retrofit
#Gyro-Stabilizers #USAYachtStabilizers #Truston #W&O  #AdvancedMechanicalEnterprises                    #Rybovich

Tight coordination between the Professional Engineer, certified welders, qualified divers, ABS and the Client can be challenging but with good foresight and communication can be accomplished efficiently. 
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NAVAL ARCHITECTURE – meet all design criteria Codes and Standards
A weld plan is developed to ensure high quality and give direction to the welders. Aluminum hulled vessels require careful development of ABS approved welding procedures for welding to the hull. ABS pre-approved and traceable pipe, plate, welding filler, welders and welding processes is required. Additional hydrostatic testing may be required in-situ for through hull penetrations. Aluminum has a higher specific heat capacity and thermal conductivity than carbon steel. Due to this it is critical to have a hyperbaric barrier between the hull and the surrounding seawater to inhibit quenching of the weld zone and subsequently higher levels of entrapped porosity within the welds. Typical welding processes for aluminum are GTAW (gas tungsten arc welding) or GMAW (gas metal arc welding) with a mandatory pre-heat of the base metal to remove moisture. ABS approved design drawings are issued by the professional engineer for modification of the hull structure. ABS will require NDE (non-destructive examination) of the hull welds to ensure quality levels are met.
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SHIP-FITTING PROJECT MANAGEMENT – ensure ABS approved design drawings are followed
Different plate locations within the same hull can require more aggressive cleaning to produce a pure weld puddle. Electrode batch quality can vary. GTAW can produce higher quality welds because the process demands greater control of the welding, however GTAW also requires more welder skill and has a lower deposition rate.  
 
Please contact us for your next ship structural refit beneath the waterline.
Shawn Henderson, P.E.
Shawn@Ocean-Engineers.com