HUGO: Hawai'i Undersea Geo-Observatory--Experimenter's Guide



HUGO is an ocean bottom observatory open for use by all marine scientists within the hardware limitations of the observatory. HUGO supplies electrical power and command capability to experiments on Loihi seamount, and transmits data from experiments to shore at Honuapo, Hawai'i. The main HUGO cable was emplaced on October 12, 1997, and HUGO should be open for experiments in the summer of 1998. At its full potential HUGO will have the capability to service more than 80 experiments. This guide is designed to aid potential experimenters in proposing and designing experiments.

Loihi seamount is the only known active submarine volcano in U.S. waters, located about 20 miles off the southeast coast of the Island of Hawai'i (click on the figure to the right to see the location of Loihi).It suffered a large volcano-seismic event in July, 1996, and is likely to still be erupting. Readers are directed to the Hawai'i Center for Volcanology's Loihi page for other information on Loihi.



4.0 EXPERIMENT DESIGN AND CONSTRUCTION TIMELINE: The following scenario is supplied as a possible model for how an experimenter might perform a HUGO Experiment.

  • 4.1. Experiment conceptual design and scientific rationale. The experimenter plans an instrument for scientific measurement of some parameter on the ocean floor.
  • 4.2. Contact HUGO. The experimenter contacts HUGO to be placed on the mailing list and to obtain the latest revision of this document. (
  • 4.3. Write proposal. The experimenter writes a proposal to the appropriate funding agency to design, construct, emplace, and analyze data from the experiment. It may be beneficial to contact other HUGO experimenters at this point to write joint proposals and increase odds for funding. The HUGO Project will supply projected costs for HUGO parts, installation, and HUGO system overhead.
  • 4.4. Equipment and scheduling. On successful funding, the Experimenter should immediately contact the HUGO Office to plan parts procurement, submersible interface information, and installation schedule. If location at a particular site on Loihi is desired, considerable advance warning is needed to ensure that system hardware is available in the area. A proposal for use of the submersible will be submitted to HURL in conjunction with other HUGO operations.
  • 4.5. Instrument design and construction. HUGO engineers will be happy to make suggestions on Experiment design. Some basic guidelines are: no glass buoyancy, use foam; use titanium for pressure housings; keep power drain to a minimum; consider the possibility of recovering your package.
  • 4.6. Testing. On completion, the instrument will be shipped to the University of Hawaii for testing at the HUGO System Test Bed. This test bed will emulate the HUGO system, and nominal operation of instruments at the Test Bed will ensure proper operation in HUGO.
  • 4.7. Installation. The experiment will be carried to the bottom with the submersible, or lowered to the bottom from a surface ship, and subsequently connected to HUGO and moved to its proper location using the submersible. Data will be available as soon as power is turned on to the appropriate connector at the Mux Node. During emplacement, the experimenter can monitor data in real-time through the receiver card in his/her computer at the shore station.
  • 4.8. Long-term data recording and dissemination. Each Experimenter will be supplied with data from his/her experiment. Experimenters will be able to view subsets of their data via Internet connections, and data will be stored on site and transmitted to experimenters in an appropriate format. Technology for data recording and distribution changes continuously, and the HUGO system will not settle on a particular storage medium and communication scheme until necessary. Experimenters will be charged an appropriate overhead for data collection, storage, and dissemination.


The HUGO System became operational in January, 1998, thus it is expected that the first set of experiments could be installed in September, 1998. Mux Nodes will be added to HUGO in appropriate locations on Loihi depending on the demand by funded experiments. HUGO is designed to operate for at least ten years.

Weight:Less than 100 lb. in water.
Size: 0.7 m on a side or smaller (for the submersible to carry it to the bottom.
Materials (for permanent experiments):

Mechanical strength members:

Pressure vessels:



titanium 6" id tubes

Power Consumption: nominal: less than 5 Watts continuous.
Power voltages at Experiment: (supplied by Interface Module):nominal:

+5 volts TTL

15 volts, analog supply

Clock Rate supplied (Interface Card):819.200 kBaud with sub-multiples
Data rate from Experiment:

connected to Level 1 Mux Node:

connected to Level 2 Mux Node:

16,000 samples/s (655.360 kBaud)

2,048 samples/s (81.92 kBaud including 8 frame sync bits per word)

Data word format::see Table 2 below
Components supplied by HUGO:

Interface Module:

Receiver Card:

connectors and cables:

Approximate cost: $4,000

Approximate cost: $3,000

costs vary with experiment and length of cable

data type:byte 1byte 2*byte 3byte 4
8 bit data system byte MXXXXXXX 00000000 CCCGGGGG
12 bit data system byte MXXXXXXX XXXX0000 CCCGGGGG
16 bit data system byte MXXXXXXX XXXXXXXX CCCGGGGG
24 bit data system byte MXXXXXXX XXXXXXXX XXXXXXXX
12 bit double rate system byte MXXXXXXX XXXXMXXX XXXXXXXX

system byte: supplied by HUGO
M: most significant bit of data sample
X: data bit
C: user bit
* data must be left justified for proper quick-look decoding at shore station

HUGO Experimenter's Guide Rev. 2.0

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This page created and maintained by Jackie Caplan-Auerbach