BGM-3 Interface

Joe Stennett's interface for Bell BGM-3 Marine Gravity Meters. This interface replaces the original Bell hardware which produced a BCD encoded digital output to an HP85 control computer which wrote a 9-track magnetic tape.

Joe's interface uses the four (4) Hertz clock output derived from the BGM-3's internal timebase and the output frequency (nominally 25 kHz) that is proportional to the measured gravity. It also monitors two digital error outputs.

From these inputs it generates an asynchronous serial (RS-232C) output message with the frequency and two status bits.

Healy Multibeam Replacement

In 2003 I presented a plan to the UNOLS Arctic Icebreaker Coordinating Committee and NSF to upgrade the multibeam (seafloor swath mapping) capability of the the US arctic research icebreaker Healy (which is operated by the US Coast Guard.) In November, 2009 Healy went into drydock to remove the existing SeaBeam 2112 and install a Kongsberg EM122


An open source software package for processing swath (mostly) seafloor multibeam data.
The home page for MB-System is at:
Downloads by anonymous ftp for MB are available at:
A read-only web interface to the Subversion repository for the MB-System source code is available at:


A deep-towed seafloor mapping sonar developed in collaboration with International Submarine Technology (IST.) The Lamont project was lead by William B. F. Ryan with engineering and operational support by Dale Chayes.

Jim Kosalos, Larry Robinson and Irv Bjorkheim were the early principals in IST.

The first SeaMARC was built in early 1980 and fielded in search of the Titanic for in the summer of 1980.

The name is an acronym: Seafloor Mapping And Remote Sensing