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DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV

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Page 1: DIGIPILOT Development-MARAD Fundsautomatemarine.com/wp-content/uploads/DIGIPILOT... · DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV The M/V St. Clair was built

DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV

Page 2: DIGIPILOT Development-MARAD Fundsautomatemarine.com/wp-content/uploads/DIGIPILOT... · DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV The M/V St. Clair was built

DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV

Page 3: DIGIPILOT Development-MARAD Fundsautomatemarine.com/wp-content/uploads/DIGIPILOT... · DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV The M/V St. Clair was built

DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV

Page 4: DIGIPILOT Development-MARAD Fundsautomatemarine.com/wp-content/uploads/DIGIPILOT... · DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV The M/V St. Clair was built

DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV

Page 5: DIGIPILOT Development-MARAD Fundsautomatemarine.com/wp-content/uploads/DIGIPILOT... · DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV The M/V St. Clair was built

DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV

Loran C Potential for Chart Line Referencing on DIGIPLOT PPI1 During DIGIPLOT’s developmental sea testing on “Tradewinds,” the use of Loran C was discussed with several fishermen who bragged about Loran C’s “repeatable accuracy” and the ability to return to the same spot in spite of the fact that its conversion to latitude and longitude for charting was imprecise, only achieving .25 nm 2d rms (<460m) AUTO-MATE’S Navigation complement to DIGIPLOT with its own separate computer 3 American Steamship had bought a DIGIPLOT for their newly built 1,000-foot ore carrier, which operated only on the Great Lakes. After installation and satisfactory use, the Captain said that he appreciated DIGIPLOT’s anti-collision operation, but since congested traffic wasn’t his biggest problem, he asked if there was a way to draw north referenced properly positioned chart lines on the PPI to help guide his extremely long vessel into a proper entrance channel into the narrow St. Mary’s river in poor visibility. It was recognized that although Loran C’s positional accuracy was only .25 nm, its 60 to 300 ft “repeatable accuracy” might enable use of a single point calibration to display sufficiently accurate referenced channel entrance guidelines on the MV St. Clair’s radar PPI. A quick implementation of the hyperbolic conversion software was accomplished for line display using the DIGIPLOT. The US Department of Commerce Maritime Administration (MARAD) had funded the subsidized ship built equipment purchases for the experiment which was planned to initially utilize the “backside” of the US Coast Guard’s “East Coast Loran C chain” and later, their newly built “mini-chain” to provide even better than 0.1 nm accuracy for the navigation approach guidelines to the river entrance. By comparison with a manual Loran C chart solution, an accuracy of less than 0.1 nm (<600 ft.) was first achieved on the American Steamship’s MV St. Clair (a 40k dwt 1000 ft Great Lakes ore carrier) on July 14, 1975, utilizing the “repeatable accuracy” of the “single point calibration. ” This accuracy was deemed adequate for successfully referencing a guideline approach to the St. Mary’s river entrance on Iotron’s DIGIPLOT fully automatic radar plotter PPI. produced more independently verified better accuracy of the entrance navigation line positioning experiment.

MARAD DIGINAV/Loran C with Experimental DIGIPILOT

1 Excerpts from: Genesis of Loran Augmented Satellite Navigation John C. (Jack) Herther The MITRE Corporation, 202 Burlington Road, Bedford, MA 01730 E-book browse http://ebookbrowse.com/genesis-of-loran-augmented-satellite-navigation-pdf-d11092814

Page 6: DIGIPILOT Development-MARAD Fundsautomatemarine.com/wp-content/uploads/DIGIPILOT... · DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV The M/V St. Clair was built

DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV

The M/V St. Clair was built by under U.S. Maritime Administration Subsidy Bay Shipbuilding at Corp at Sturgeon Bay, Wisconsin and entered service in May 1976 and is used for the long-haul transport of iron ore pellets, coal, and limestone. The M/V St. Clair is powered by three 3500 HP General Motors Electro Motive Division (EMD) diesel engines. For maneuvering in port the vessel is equipped with 1,000 HP bow and stern thrusters.

The Course, Yaw Rate and Rudder Angle data plots represent typical performance of DIGIPILOT’s fuel saving implementation on MARAD funded equipment on American Steamship furnished vessel testing of Loran C and the ad-on digital autopilot in various operational conditions after a nearly 5 year laboratory and at sea development period.

DIGIPILOT - A Self Adjusting Digital Autopilot for Better Maneuvering and Improved

Course and Track Keeping By John C. Herther, Francis E. Warnock, Kenneth W. Howard of iotron Corporation in

Collaboration with Dr. Wallace Vander Velde of the Massachusetts Institute of Technology.

Careful comparison of DIGIPILOT AutoHELM performance against either gyro pilot or manual steering shows steering using much smaller, quicker rudder deflections while decreasing the amount of yawing and holding course more tightly thus saving 1 to 3# fuel in various sea states.

The first set of plots contains detailed information recorded on the US Flag MV ST. CLAIR entered service in May 1976 on the US Maritime administration subsidized ship building program. The MV ST. CLAIR is a Great Lakes ore carrier about 40,000 DWT and measuring 770 feet in length beam 92 feet owned by American Steamship Company. DIGIPLOT Collision Avoidance and a Loran C DIGINAV were purchased by the forward thinking owner with 50% subsidy even there wasn't enough traffic in the Great Lakes that wasn’t dense enough to fully justify the ARPA’s need.

Page 7: DIGIPILOT Development-MARAD Fundsautomatemarine.com/wp-content/uploads/DIGIPILOT... · DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV The M/V St. Clair was built

DIGIPILOT Development-MARAD subsidy for ship with DIGIPLOT & NAV

Schematic of DIGIPILOT functional operation (Patent Pending)

Course (Fuel Saving) or Precise Track Following Command-manual or ECDIS source Shipʼs or internal system parameters for “all seas” adaptive autopilot optimization

• Fluxgate Compass if no gyro • Shipʼs Gyro Compass • Shipʼs Speed or Doppler Log • Rudder angle transducer added if not installed • Rotary, linear or hydraulic rudder drive to match various steering systems • Yaw Rate Gyro-2 deg/min turn rate, ideally@ Bendix bias of +/-0.05 deg/sec • Fuel Flow measurement instrument digital input for performance comparison • GNSS COG and SOG, also if Loran C/e, ideally, True Heading to 1 mr 95% • 6 axis IMU-Three gyro-accelerometers for system use or development instrumentation • RPM for speed and propeller pitch for billing and/or development improvement • Doppler log for development only not on system (since not on most older vessels) • SatCom-Iridium for SW data insertion & improvement comparison trials in environment