Near vertical dropoff at edge of reef on Eleuthera Island. Record from Ship PEIRCE off Eleuthera Island, Bahamas, 1984

Earliest surviving astrolabe - constructed approximately 927 A. D. Resided in the Kuwait National Museum prior to Gulf War. From Scientific American, April 1986

Astrolabe used by Samuel de Champlain. From America' s Beginnings, p. 25

Determining Latitude from the shore. From Robert Dudley's Secrets of the Sea - 1649

A mariner's compass with alidade for determining azimuth

Determining Latitude

Ancient text demonstrating use of cross-staff

MAYFLOWER mariner demonstrating use of cross-staff. At Plymouth State Park, Plymouth, Massachusetts

Octant with simple artificial horizon in the form of a pendulum

Plath sextant

Captain Nemo taking a star sight from the deck of the NAUTILUS

An octant

Taking a sun sight. Navigating on the MALCOLM BALDRIGE

Hubert Paton taking a sun sight. Navigating on the LYDONIA

George L. Anderson taking a sun sight. Navigating on the EXPLORER

Joe Partington taking a morning sun sight. Robert Munson recording

Flash and sound ranging survey as practiced by Charles Wilkes. Shoot cannon - see flash - measure time till hear sound - determine distance

Freddie Jeffries taking a sun sight. Navigating on the SURVEYOR

Signal built on tree at Station WADE. Party off of HYDROGRAPHER

Signal at Isle Chandeleur. Party off of BACHE

Completed 100-foot signal. Note man at top. Party off of HYDROGRAPHER

Station Mud - built in 12 feet of water and no telling how much mud. Party off of Launch ELSIE III

Building a 100-foot tall hydrographic signal

A completed hydrographic signal. Multiple colors for identification from offshore. Signal for OCEANOGRAPHER operations

Building a large hydrographic signal. Multiple colors for identification from offshore. Party off of OCEANOGRAPHER

On top of Station PERP. Party off of EXPLORER

Large hydrographic signal. Photograph in 1931 Hydrographic Manual

Building a tri-pod type signal. Photograph in 1931 Hydrographic Manual

Hydrographic signal as seen from sea

A pole signal at Station Clarence Astro. Party off of EXPLORER

Tripod signal on south coast of American Samoa. Built by party off of SURVEYOR

Station Pic at west end of Picara Point. Building party off of WHITING

Station Pic at west end of Picara Point. Building party off of WHITING

Building signal at Station Out. Building party off of WHITING

The way to Station Can. Building party off of WHITING

Signal and navigation trisponder at Station Can. Installation by party off of WHITING

Signal and navigation trisponder at Station Can. Installation by party off of WHITING

Station Hans at south end of Hans Lollik Island. Building party off of WHITING. Note century plants and desert aspect of island

Triangular hydro signal. Building party off of PATHFINDER

Hydro signal being built for calibration of Raydist system. Building party off of NOAA Launch 1257. Glenn Hendrix kneeling, Steve Lloyd standing

Signal building party off of PEIRCE

Large tripod signal being built. Building party off of PEIRCE

Signal building party in Southeast Alaska. Party off of PATHFINDER

Signal in Prince William Sound

Signal in Prince William Sound

Signal in Penobscot Bay. Signal built by party off of PEIRCE

Dismantling the signal at Station Out, Thatch Cay. Cleaning up at the end of a project. Lt.(j.g.) Mike Kuhl cutting wire securing signal

Flags on bell and whistle buoys. Using harbor buoys for signals for survey work off the BACHE. Black flags showed up best

Planting a survey signal buoy. Off LYDONIA or NATOMA

Constructing a floating buoy signal. Buoy in place. For use by East Coast wiredrag party