Marine Technology - Assets & Development

Standards being adopted:

* The Professional standard for full research and recovery of Marine sites mandates a need for archeological integrity and a priority interest in preserving and assuring provenience of in situ documentation prior to moving or removing any shipwreck material. With the advent of hi resolution digital in camera grid processes and real time ability to establish exact coordinates and the addition of AUV and ROV equipment -this reduces and often eliminates entirely the hazards and pitfalls of human error or risk by eliminating the need for underwater human presence during much of this hereto fore intensive and tedious process. Indeed, this frees up the manpower to analyze and observe the overall site and allows the social scientists more time to do hands on in the field Marine Archaeology. Advanced technology has profoundly improved our cost effectiveness of recovery and the Ocean frontier is vastly more accessible now than it ever was.

Vector M5 is a portable high performance ROV system, combining superior power, telemetry and payload with each of use, ruggedness and reliability - providing a powerful overall performance envelope and versatility compared to other vehicles of its class. It has five high performance thrusters - four vectored and one vertical.
*The power and control system is network architectured for simplicity and ease of use, with multiple micro-processors providing redundancy and expanded capabilities. The design incorporates intuitive, computer-aided, always active diagnostics facilitating maintenance of the system in the harshest environments by technicians with a minimum of training.
*Specially designed high performance brushless thrusters provide the highest power to weight ratio and reliability vs. other vehicles in this class.
*The graphical user interface (GUI) with multiple menu screens, provides intuitive feedback and active user control for ease of vehicle handling, navigation, collection and display of sensor data, as well as setting and storing custom system configurations.
*Fabricated using modern marine grade aluminum and composite materials, the chassis is totally modular with quick access to all the parts for ease of servicing and replacement as required. Constructed from polypropylene, the chassis is resilient, non-corroding and maintenance free. Ancillary equipment is easy to mount and integrate.

Camera Unit: DOE 18:1 color zoom camera unit.
Depth rating: 1000m
Resolution: 470 lines of TV
Sensitivity: 1 Lux @ f1.4
Viewing angle: 7 degrees-58 degrees
Length: 241mm (9.5in)
Diameter: 89mm (3.5in)
Weight in water: Neutral
Air-weight: 1.4kg (3lb)
Camera tilt platform: DOE electrically driven tilt actuator providing a smooth tilt speed. Operational are ± 90 degrees from horizontal, with adjustable stops.

User Interfaces: The Graphical User Interface (GUI) provides intuitive feedback and active graphics for easily controlling vehicle handling, navigation and sensor data collection. The GUI includes several menu screens with readily accessible information to guide connectivity, setup, pre-dive checklist, navigation, inspection, post-dive checklist, diagnostics and an online searchable technical manual. The ergonomic hand controller can override the GUI/OSD (On Screen Display) computer, providing redundancy and back-up.

On Screen Display: This is a continually updated video display, which provides the operator with intuitive compass rose heading, depth, turns count, elapsed time, water leak alarm and much more information, allowing the vehicle to be operated safely. It may also be used to display sensor data such as temperature, altitude or GPS position on the screen. Additional digital and analog I/O channels and vehicle data may be exported to the navigational or survey computer.

Chassis: A modular chassis manufactured from polypropylene. This extremely rugged material is maintenance free, self-supporting in water and non-corroding - providing the vehicle with an energy absorbing protective framework. Ancillary equipment are easily mounted on the frames and bottom panel.

Propulsion: Fully pressure compensated, high performance DC brushless thrusters. The high torque, gearless thruster design is highly robust and quiet. A hydrodynamic nozzle provides symmetric thrust with a compact form factor. Careful attention to component design and materials for reliability and ruggedness, such as the use of high quality industrial mechanical seals, provide a long, dependable and near maintenance-free operational life.

Vehicle Electronics/Telemetry: Continuous full control and diagnostics of onboard vehicle functions through a digital communications link. Standard configuration includes up to three continuous video channels over TSP (Twisted Shielded Pair), and expandable digital telemetry over copper including RS232, RS485, Ethernet and options for fiber-optic.

Navigation: Rate gyro stabilized, solid-state magnetic compass unit: resolution ± 0.1 degrees, accuracy ± 0.5 degrees, update rate 50mS. Electronic depth sensor: accuracy 0.25% of fsd.

Auto-pilot: Selectable automatic pilot for auto-heading, autodepth and optional auto-altitude.

Lighting: 2 x 250 watt Quartz-halogen lamp units. The control is On/Low/Medium/Full.

Power requirements: Input 230V AC, 50/60 Hz, 10 kVA, single or 3-phase. On-board user power available - instrumentation 24 VDCC, auxiliary power at up to 400 VDC.

Umbilical cable A supple, rugged cable, designed for harsh ocean environment with a 1000lb working load: neutrally buoyant in fresh water, diam. 0.6in (16mm); or optional smaller diameter without floatation jacket (heavy) at 0.5in (12.5mm).

Options Fiber-optic telemetry, sonar systems, tracking systems, specialized cameras, cable reels (manual or powered), various manipulators, additional tools and sensors, spares kits, technical training.

A basic Side Scan Sonar System is shown above. It consists of a topside processing unit, a cable for electronic transmission and towing, and a subsurface unit (a tow fish) that transmits and receives acoustic energy for imaging.
Side scan sonar is a method of underwater imaging using narrow beams of acoustic energy (sound) transmitted out to the side of the tow fish and across the bottom. Sound is reflected back from the bottom and from objects to the tow fish. Certain frequencies work better than others, high frequencies such as 500kHz to 1MHz give excellent resolutions but the acoustic energy only travels a short distance. Lower frequencies such as 50kHz or 100kHz give lower resolution but the distance that the energy travels is greatly improved.
The tow fish generates one pulse of energy at a time and waits for the sound to be reflected back. The imaging range is determined by how long the tow fish waits before transmitting the next pulse of acoustic energy. The image is thus built up one line of data at a time. Hard objects reflect more energy causing a dark signal on the image; soft objects that do not reflect energy as well show up as lighter signals. The absense of sound such as shadows behind objects show up as white areas on a sonar image.

Sub Sea's 4100 Side Scan Sonar System is the long lasting workhorse of hydrographic surveying. The topside processor is either a 19-inch rack mountable case (4100) or a water resistant portable system (4100-P). EdgeTech's DISCOVER Side Scan Sonar software runs on the 4100 and 4100-P.
The Model 272 towfish is a hydro dynamically stable, towed body that contains the electronics and transducers necessary to generate and receive side scan sonar signals. It is designed for use at depths up to 1000 meters. Various tow cable systems provide the mechanical means for towing the fish near the seafloor and the electrical means for powering the fish, triggering the transmitters, and sending the return signal to the topside for processing and display.
The Model 272-2 towfish incorporates circuits for transmitting and receiving the 100kHz side scan sonar frequency. The Model 272-TD towfish operates at either 100kHz or the higher resolution 500kHz selectable in the DISCOVER software.
Both the Model 272-T and 272-TD towfish feature the patented Saf-T-Link shear pin feature. When cable tension on the towfish exceeds 180 Kg (400lbs.) due to snagging on the seafloor or mooring lines, the nylon pin shears and the electrical connector between the cable and towfish separates. The towfish then "flips" 360 degrees, transferring the tow point to the nose of the towfish and allowing it to be pulled clear of the obstruction. Normal operation is easily restored by remounting the towing arm with a new shear pin and refastening the connector. If only the tail fins snag, they will fall away and be loosely held by a nylon cord. The cord is designed to break if the snag persists to avoid loss of the towfish.
Both the 272-T and the 272-TD features a patented Time Varied Gain (TVG) circuit that compensates for the known signal losses versus range. This not only facilitates processing, but also reduces the dynamic range requirements of the tow cable, thus reducing the susceptibility to electrical nose pickup.
The Model 272-T and 272-TD can both be towed with lightweight Kevlar tow cable or, for deeper waters, by double armored steel-cables.

The 4200 Series utilizes EdgeTech's Full Spectrum CHIRP technology to provide crisp, high resolution imagery at longer ranges than conventional side scan systems. The 4200 Series comes available in two different versions; the 4200-SP and 4200-MP. The 4200-SP acts as a traditional side scan system whereas the 4200-MP is a dual mode system with an added High Speed Mode (HSM) of operation.
The two software selectable modes of operation for the 4200-MP are as follows:
*High Definition Mode (HDM) - conventional dual simultaneous frequency operation with extra long array for superior resolution; excellent tool for Mine Countermeasures (MCM).
*High Speed Mode (HSM) - utilizes EdgeTech's Multi-Pulse technology which places two pulses into the water rather than one. This allows the system to be towed at speeds of up to 10 knots while meeting NOAA and IHO-44 requirements for minimum 3 pings on a 1 meter target compared to conventional systems at only 4 knots.
The array configuration for the 4200-MP's two modes of operation is dynamically reconfigured by the system to suit the user's immediate application. Real time selection of the 2 modes allows the user to choose the mode best suited to his task at hand.
The 4200 Series utilizes EdgeTech's Full Spectrum CHIRP technology to deliver wide band, high energy transmit pulses, coupled with high resolution and superb signal to noise ratio echo data. The systems employs wide band, low noise front end electronics which reduce system induced phase errors and drift to negligible levels. The sonar data is also available as a complex, fully coherent data set suitable for advanced user applied post processing.
The 4200 Series is also designed to allow efficient integration of other optional sensors. The EdgeTech telemetry link allows the sonar signals that are digitzed in the towfish to be transmitted over long coaxial cable lengths with no loss of signal quality.
The 4200 Series offers two towfish options based upon the user's desired applications; a stainless steel or lightweight aluminum version. The stainless steel towfish is ideal for deeper water operation of up to 2000 meters and the lightweight aluminum towfish for shallower operation of depths up to 500 meters.
Along with the choice of towfish, the 4200 Series also offers three different topside processor options which again allows the user to customize the system to best suit his needs. All of the topside processors come installed with EdgeTech's DISCOVER software, which serves as the control and data acquisition sub-system for display, storage and printing of sonar data. You also have the option of configuring the system for third-party interface and/or utilizing your own PC/laptop.
The EdgeTech Model 4200 Topside Processor is a standard 19" rack mountable topside that is ideal to use on larger vessels or when portability is not a main concern. In this configuration, all of the electronics are housed within a 19" rack mounted Windows based PC system and the data is displayed on a high resolution flat screen color monitor.
The EdgeTech Model 4200-P Topside Processor is a portable unit that is ideal for smaller ships or when operating outside of a protected area. All of the electronics are mounted within a waterproof "suitcase-style" housing and the data is displayed on a splashproof laptop computer via a wired or wireless Ethernet connection.
For customers who would prefer to use their own 3rd party topside processor, EdgeTech offers the 701-DL (Digital Link) which acts as the interface between the 4200 Series towfish and the display and acquisition software. Witht his option the user supplies the PC and runs the 4200 System using EdgeTech's DISCOVER software.
The 4200 Series sets new standards in the industry for seafloor mapping by integrating key performance and safety features, the dual mode feature along with EdgeTech's Secondary Recovery System, Standard Heading, Pitch & Roll, optional Depth, Magnetometer interface and Acoustic responder for accurate towing positioning at a price which is commercially sensitive.

The integration maintains the basic system integrity of each subsystem, allowing each to be used separately or together. In integrated mode, power and data multiplexing are supplied from the System 2000 to the G-880G, which is towed eight meters behind the side scan sonar. At the surface the magnetometer data is separated from the sonar data by the System 2000 Display/processor unit and transmitted to the Data Display and Processing Unit. The magnetic gradients and sonar data are concurrently logged with DGPS position data acquisition and processing station. The combined data affords improved target acquisition, accurate spatial plotting and characterization of target size and depth.

Magnetometers detect ferrous metals that could be attracted by a magnet. Steel, iron and iron rich rocks. A good way to remember this is that ferrous metals (detectable) rust or stain yellow/orange. A vessel towed magnetometer will read the earth's magnetic field and when towed in an area of ferrous metals (such as rusted debris from a shipwreck) the magnetometer will detect the magnetic disturbance the rusted metals generate and produce readings to allow the operator to distinguish size and location.

Magnetometers will not detect or "see" nonferrous metals. Gold, silver, lead, copper, aluminum, and some stainless steel. A highly sensitive proton magnetometer is capable of detecting ferrous metals utilizing an omni-directional detector towed behind either a ship or plane. In Marine applications it is advised to tow the sensor at least 3 times the vessel length to minimize the ship's influence on readings. Magnetic measurements, taken at an interval between 0.5 seconds and 999 seconds, are displayed on an LED display, recorded into a computer via an RS232 interface.

The model G-882 cesium-vapor marine magnetometer provides the same high performance as our airborne instruments delivering high resolution results in all types of survey applications. The G-882 is a low cost, compact system designed for professional surveys in shallow or deep water.

The G-882 magnetometer's digital output can be recorded with any serial data logger but its full potential is obtained when used with our MagLog Lite software to log, display and print GPS positioned measurement results. The price, performance, and reliability of the G-882 make it the best value of any marine magnetometer today.

The G-882 is designed for operation from small vessels for shallow water surveys as well as for large survey vessels for deep tow applications (4,000 psi rating, telemetry over steel coax available to 10Km). Being small and lightweight (40 lbs net, no extra weights) it is easily deployed and operated by one person. Power may be supplied from a 24 to 30 VDC battery power or the included 110/220 VAC power supply. The standard G-882 tow cable includes a Vectran strength member and can be built to up to 700m (no telemetry required). The shipboard end of the tow cable is attached to an included junction box or optional onboard cable for quick and simple hookup to power. Output data can be recorded on any Windows 98, ME, NR, 2000 or XP computer equipped with RS-232 serial ports. Best of all, the rugged G-882 is designed for and has been used successfully everywhere in the world for all types of applications.

The G-882 Cesium magnetometer provides the same operating sensitivity and sample rates as the larger deep tow model G-880. MagLogLite Logging Software is offered with each magnetometer and allows recording and display of data and position with Automatic Anomaly Detection! Additional options include: MagMap2000 plotting and contouring software and post acquisition processing software MagPick.

HYPACK is the most widely used hydrographic software package in the world. Here's why.
HYPACK provides all of the tools necessary to comlete your hydrographic, side scan and magnetometer survey requirements. With over 4,000 users around the world, HYPACK provides you with the tools necessary to meet almost any hydrographic survey requirement. It provides tools to design your survey, collect your data, apply corrections to soundings, remove outliers, plot field sheets, export data to CAD, compute volume quantities, generate contours, create side scan mosaics and create/modify electronic charts.
Read on for additional information about HYPACK's capabilities.
Design Tools
HYPACK contains powerful tools that let you quickly design your survey. Design tools allow you to:
*Set your geodetic parameters.
*Import background charts: DXF, DGN, S-57, TIF, MrSid, ARCS.
*Configure your survey equipment: equipment type, connection information, offset information.
*Create your planned lines: manual entry, parallel and perpendicular patterns, CHANNEL DESIGN automatically creates planned lines and cross sectional profiles for channels and turning basins, ADVANCED CHANNEL DESIGN creates complex 3D surfaces for precise dredging and volume computations.
HYPACK automatically stores your survey information to a project directory, allowing you to quickly load previous surveys. It runs under Windows XP and Windows Vista.

Survey
HYPACK's SURVEY program provides you with the power and flexibility to quickly complete your survey work. SURVEY accepts input from GPS, range-azimuth systems, echosounders, magnetometers, telemetry tide systems, and over 200 other sensors. It also provides positioning data for our SIDE SCAN SURVEY program (a standard part of HYPACK) and the HYSWEEP Multibeam SURVEY program (an optional module of HYPACK).
The SURVEY program allows you to track multiple vessels. You can track your own survey vessel, or a vessel and a towfish, or a vessel and an ROV or multiple vessels with the same easy-to-use program.
HYPACK's time stamping and clock synchronization routines are the industry's best. Our SURVEY program was the industry's first in using RTK GPS to determine real time water level corrections (RTK Tides). SURVEY remembers the screen layout and restores it each time you start. The SHARED MEMORY programs allow you to share real time SURVEY data with other applications.
The 3DTV program can be run simultaneously with SURVEY to give you stunning real-time visualizations of the vessel or ROV's position over a surface model.

Editing
HYPACK provides graphical editing and sounding selection routines that allow you to quickly prepare your survey data for plotting, export to CAD or several other final products. The SINGLE BEAM EDITOR of HYPACK provides for:
*Graphical review and editing of tracklines and depth profiles: display of acoustic profile for network capable soundings, display of design templates and previous survey profiles.
*Water level (tides) adjustments: real time telemetry gauges, manually entered tides, RTK tides, tide adjustments between stations.
*Sound velocity corrections.

Survey
There are several options for sounding reduction, depending on your final product.
*SORT: Selects the shoalest soundings and prevents overwrites.
*CROSS SORT: Selects random soundings and packs them in tight.
*SOUNDING SELECTION: Selects min/max soundings and fills in between.
*MAPPER: A binning routine that can select minimum, maximum, average, closest to cell center to represent each cell.

Volumes
HYPACK ability to compute volume quantities is unsurpassed. It can compute volume quantities either from sections across channels or from surface models (TIN MODEL).
The CROSS SECTIONS AND VOLUMES program quickly computes volume quantities for cross sectional profile lines compared to the channel design template and channel overdepth template for each line. The program is the de facto standard for volume computations by several national survey agencies. Over 20 methods are available to compute the area and volume of material for each profile segment (left slope, main channel, right slope), it can compute quantities for a single survey versus the design template, or for a pre-dredge versus an after-dredge comparison. CROSS SECTION AND VOLUMES can read hundreds of sections, compute the volumes and send all of the sections to the printer/plotter in a matter of seconds. The latest capability added is support of beach volumes for beach replenishment projects.
The TIN MODEL program of HYPACK can be used to compute several types of volume quantities. Input data can be from single beam, multibeam, or multiple transducer surveys.
*Reservoir volumes: Computes the volume and surface area of a reservoir at user-defined water levels.
*Channel volumes: Computes the volume quantities of the TIN surface versus a set of planned lines and their channel design templates.
*ADVANCED CHANNEL DESIGN volumes: Computes volume quantities of the TIN surface versus a complex area created in ADVANCED CHANNEL DESIGN.
*Survey versus Survey volumes: Computes the volume quantity between two different surveys of an area.

Side Scan
HYPACK is the only hydrographic software package that offers side scan collection, mosaicking, and targeting as a standard part of our package. The SIDE SCAN SURVEY program supports analog and digital side scans, including some of the latest dual frequency and high resolution side scans.
HYPACK's side scan processing routines accepts input from side scan or from the pseudo-side scan available from many multibeam systems. It can also handle XTF files from several side scan manufacturers own logging software.
Targeting can be performed in real time, or in post-processing in the SIDE SCAN MOSAIC program. Target measurement tools can be used to capture a GeoTIF image of each target, make measurements of its length, width and height, and save it to a Target Book. The Target Book is in Rich Text Format and can be emailed and reviewed by clients or home offices in Microsoft Word.
In HYPACK Version 2008, the GEOCODER program was integrated as a standard side scan processing tool. GEOCODER was developed by Dr. Luciano Fonseca of UNH-CCOM and provides advanced mosaicking and bottom classification routines.

Plotting
HYPACK's plotting program (HYPLOT) allows you to send any combination of data files to your plotter or printer or to a PDF file. All of the background files that can be displayed in HYPACK can also be printed/plotted in HYPLOT. This allows you to create stunning plots with your background files, such as ortho-photos (TIF), engineering plans (DXF/DGN), electronic charts (ENCs, ARCS), superimposed with your hydrographic survey data.
HYPLOT has several border and title block options, including the national borders used by USACE, China and Russia. You can plot X-Y grids (or tics), local projection lat-long grids (or tics) and WGS-84 lat-long grids.
Another BIG feature of HYPLOT is the ability to send the photos out to a DXF file. This allows you to transfer the entire plotting sheet (with borders and labels!) into your CAD/GIS package.

Export to CAD
HYPACK knows that many of our users want to be able to bring their survey data into their CAD/GIS package. We have spent a lot of time and effort to make sure that all of our files can be exported to DXF, DGN and ASCII formats for input into AutoCAD, Microstation, ArcInfo and other CAD/GIS packages.
Soundings, tracklines, contours (plain and color-filled), targets, planned lines, borders and other files can be converted to DXF or DGN in the EXPORT program.
The plotting sheets created in HYPLOT can also be exported to DXF.
In HYPACK 2009, we begin our import/export to Google Earth's KML format. This allows you to superimpose your survey data as a layer in Google Earth.

TIN MODEL
HYPACK's TIN MODEL program creates surface models from your survey data. The TIN (Triangulated Irregular Networks) surfaces provided extremely accurate renderings of the bottom and can be used to generate stunning graphics, DXF contours, gridded XYZ data sets, and volume computations.
The TIN MODEL program allows the user to drape a TIF on top of the surface model. This means you can overlay side scan mosaics or ortho-TIF files on the 3D seafloor.
The TIN MODEL accepts input from single beam, multibeam and multiple transducer data sets. The contouring engine inside the TIN MODEL program allows the user to control the line types, weights, colors, color fills and intervals. Contours are saved to DXF format, where they can be displayed in HYPACK or read directly into your CAD/GIS package.
The volume tools in TIN MODEL allow you to compute the following volume quantities:
-TIN versus Level (Reservoir)
-TIN versus LNW (Planned Line with templates)
-TIN versus TIN (volume above historical surface)
-TIN versus CHN (ADVANCED CHANNEL DESIGN file for complex dredge areas).
HYPACK's ENC EDITOR allows you to modify existing ENCs in S-57 format. Whether you want to move a buoy, create a new light, import the latest survey data or create an ENC by digitizing a TIF, the ENC EDITOR is a powerful tool that can perform your basic ENC editing tasks. The ENC EDITOR provides for full attribution of S-57 features and can also display IENC symbols and information from AML.
The ENC EDITOR can also be used for real time verification of ENC charts. Running side-by-side with the HYPACK SURVEY program, the user can mark targets (manually or with a hand-held laser) in SURVEY and then query ENC EDITOR for a list of features in that area. The user can then decide whether to move existing features or to create a new feature at the target position.
The ENC EDITOR is a standard feature of HYPACK.

At Sub Sea we think of our Eyeball class of ROV as small, portable, highly maneuverable system capable of deployment by hand or from a small crane or Davit. As the name suggests, these ROV's are primarily intended for video inspection, survey or observation duties. Sonar can be added to extend search and location range of the vehicle beyond the visibility of cameras and various sensors and measuring devices can also be carried. Our ROV is a lightweight remote operated vehicle with exceptional handling characteristics.
-1,000 ft rating
-360 degree rotating camera bay facilitates 3 cameras
-Variable intensity main lights and camera tracking lights
-Auto-depth, auto-heading, autopilot
-Rate gyro and magnetic compass navigation
-Video Overlay: navigation data, depth camera angles, lighting, options status, time, date, two lines free text annotation
-Other Features: Internal vacuum eliminates condensation and corrosion; multiplexed telemetry accomodates multiple sensor suites

Our ROV's unique feature is the patented meridian view port that allows the internally mounted camera to tilt and view through 360 degrees. Panning of the camera is achieved by rotating the vehicle, which can turn on its own axis. This combination of camera movement and vehicle maneuverability provides us with the ideal remote controlled sub sea video inspection package for coastal and inshore applications. Currently we use a JVC 470 line resolution, 0.95 lux color CCD camera with an F 0.8 Pentex lens as the standard video camera.

Propulsion
The ROV is fitted with four thrusters. Two main thrusters provide forward, reverse and rotational movement and two vertran thrusters provide vertical and lateral movement. Each has 5-inch diameter propellers in Kort Nozzles driven by 380-watt (1/2hp) 24 volt DC motors through 10.5:1 reduction gears.
The carbon/ceramic spring loaded shaft seals and motor brushes have a service life of 500 hours in normal operation down to 300 meters (1000 feet). They can be replaced on all four thrusters in less than an hour by removing the thruster from the outside of the vehicle. Thruster speed and direction is controlled by digital signals proportional to the movements of the joystick. Built in protection prevents overheating and overloading of motors. Ramping of motor speed is software driven through a dedicated microprocessor to give smooth operating performance.

Viewing System
The ROV is equipped with a low light CCD color video camera with a wide angle, auto iris lens. The camera is mounted on a chassis, which rotates through 360 degrees and allows the camera to view up, down, forward or backwards through a unique, patented Meridian view port.
The video picture is sent to the Surface Unit is displayed on an integral 14 inch high-resolution color monitor.

Video Overlay
Our ROV comes with the most advanced video overlay system of any ROV in its class. The overlay information can be displayed at the top or bottom of the screen or be removed. Information provided includes:
*Vehicle heading, depth, time and date.
*Auto heading and auto depth status
*Lights selected and intensity
*CP reading (if CP probe fitted)
*Manipulator open/close (if fitted)
*Camera position indicator
*Camera selected (A or B)
*Umbilical turns counter
*And two lines of free text
*Length: 21 inches (535mm)
*Width: 25.6 inches (650mm)
*Height: 22 inches (565mm)
*Weight: 90lbs (42kg)
Surface Unit: 18 x 12 x 20 inches, 92 lbs (455 x 390 x 515mm, 42kgs) Speed: 2.5 knots Payload: 9lbs (4.5kgs) Power requirements: 240 - 110 volts single-phase AC 50/60 Hz 2.5 kw max.

Underwater Handheld Detectors
Underwater metal detector technology has improved dramatically in recent years both in terms of in ease of operation as well as reliability and performance. Simply stated, a metal detector is a device that indicates the presence of metal through an audio and/or a visual signal. Modern metal detectors will locate a metal target buried under sand, mud, rocks, wood, weeds or even cement. On all detectors presently on the market, a signal is transmitted out from the search coil into the material being scanned. When the search coil passes over a metal object, the signal is reflected back to the search coil and sent to the electronics inside of the control housing. The resulting signal is then converted into an audio signal, which is heard through the underwaer headphones.

The first type of circuit used on many underwater metal detectors is the pulse induction or PI circuit. The pulse circuit has been designed to completely eliminate the effect of salt water and ground mineralization on the detector's operation and performs well under virtually all conditions. The one drawback to the pulse induction type detector is that with a few exceptions, the models currently on the market will respond to all types of metal. If you are searching around a wreck site, this would not be a problem as you would want to recover all of the artifacts present; however, if an area with a great deal of trash you would spend considerable time recovering unwanted targets. Two manufacturers have incorporated a circuit into their PI detectors that allows you to selectively eliminate some unwanted targets to avoid unnecessary digging. The operation of a PI-type detector is also the simplest to master. On most models, the only control that is used is the on/off knob as the detector automatically adjusts for the material to be searched when it is turned on. Despite the drawback of responding to all metal targets, the pulse induction is ideally suited for searching in salt water or in fresh water areas that do not contain a great deal of unwanted targets.

The second type of circuit that is used in several models of underwater metal detectors is the VLF or very low frequency circuit. The VLF circuit will automatically compensate for mineralization in the ground; however, it will not compensate for the effects of salt water at the same time. For this reason, the VLF-type detector is ideally suited for fresh water use, yet, with some practice; it can be used in salt water applications as well. On most of the VLF-type detectors, a discrimination circuit has been added. This circuit allows selectively reject specific unwanted targets such as tin foil, pull tabs, bottle caps, screw caps, and nails. If you are searching in an area such as a fresh water swimming beach that contains a large number of targets both good and bad, a VLF-type detector with a discrimination circuit would excel.

Although air happens to be the most common breathing mixture used in scuba diving, it is the least desirable gas medium for diving at any depth beyond 60 feet. Nitrox, Triox and Trimix are far more efficient in every aspect for diving to depths of 100, 150 and 300 feet respectively. Proven membrane technology now allows reliable full time production of 32% Nitrox, which is rapidly becoming the most popular gas for recreational diving. Nitrox provides nearly double the bottom time at most common depths. Low pressure compressor-driven membrane systems convert our high-pressure Pro series machines into on demand Nitrox production stations.
Triox (oxygen enriched air with helium) is the perfect breathing gas for use between 100 and 150fsw; Trimix (hypoxic Oxygen/Helium/Nitrogen mixes) is better suited for deeper exploration work. The added Helium at these moderate depths significantly reduces the insiduous impairment of hyperbaric nitrogen (Nitrogen narcosis). Divers using Triox or Trimix will experience significantly better control, increased productivity, and come home with a more memorable experience. Many dives result in stressful situations created by the sheer confusion associated with nitrogen narcosis. The narcosis distracts from the original desire for adventure and subsequently curbs further diving. Helium also makes breathing easier as a result of a much smaller molecule passing through your body's tissues. Helium, which is also far less soluble in your body's fatty tissue, is off-gassed 2.6 times faster than Nitrogen. Because your body can eliminate Helium much faster than Nitrogen, post dive fatigue is dramatically reduced with our prescribed mixtures. All successful explorations teams whether commercial, scientific or recreational enthusiast use helium mixtures.
Wreck diving is an entirely new experience with the proper equipment and breathing gas. Nearly all diving activities are more efficient, fun and safe when you learn to make the switch from air to custom breathing gasses. All specialized breathing gasses require additional training beyond basic open water Scuba certification.

High Pressure Fill Panels
*Sturdy Starboard Mounting Base
*Incoming Bank Ports With Gauges
*Incoming Compressor Port With Gauge
*CO/Moisture Indicator
*Line Valves
*Adjustable Regulator
*Filler Valves
*5,000 PSI Kevlar Hoses

High Pressure Storage
*HC-4000 Storage Cylinders (400 CuFt @ 4,500 psi)
*Stainless Steel Nut & Nipple
*OSHA Specified Horizontal Racks & Brackets
*Stainless Steel Pigtails or 5,000 PSI Kevlar Hose Pigtails
*Steel or Stainless Steel Options
*Interconnecting Plumbing for Fill Panel & Compressor to Storage Quoted Seperately

Nitrox Generators
The Litton Nitrox System provides the latest oxygen/air mixing technology available for the Nitrox gas market. Utilizing the Pressure Swing Absorption (PSA) technique, the Litton Nitrox System produces any mixture of oxygen and air between 20.9% and 93% oxygen at a user specified pressure. The Litton Nitrox System uses patented mixing technology along with field proven, solid-state oxygen sensing technology to provide you with a safe, high quality Nitrox mixture.