Tide gauge at Natzuhini Bay. Installed by party off of PATTON

Tending tide gauge at east end of Soda Bay. Party off of PATTON

Tending tide gauge at Shag Rock. Party off of HODGSON

Bubbler tide gauge at MacLeod Harbor. Installed by crew of HODGSON

Tide gauge house on pier along southeast Atlantic coast. Tides party of Gerald B. Mills

Tide gauge house on pier along southeast Atlantic coast. Tides party of Gerald B. Mills

Bubbler tide gauge installed on pier at Searsport. Party off of PEIRCE

Tidal leveling operations - connecting tide staff with bench marks. Combined operations party of C.G. Quillian Party off of GUIDE.

Tidal leveling operations - taking reading on the tide staff. Combined operations party of C.G. Quillian

Leveling to tide staff and water's edge at extreme low tide. Bubbler gauge orifice at right lower edge of photo. Improper installation necessitated leveling to assure observing lowest low water . Tidal bench mark leveling work off of DAVIDSON

Fathometer style tide gauge. Fathometer, clock, batteries, and wind generator to charge batteries. Installation by party off of PATHFINDER

Lieutenant Dale Ross holding rod during tidal leveling operations. Leveling tide staff and bench marks on Eleuthera Island. Party off of PEIRCE

Tidal bench mark leveling in Muir Inlet. Party working in vicinity of recently retreated glacier. Party off of DAVIDSON

Tidal bench mark leveling on coast of Puerto Rico. Atlantic tides party

Tidal leveling up cliff in Puerto Rico. Tieing to bench marks in vicinity of lighthouse. Atlantic tides party

Leveling to bench marks from the tide staff. Atlantic tides party

Running levels at a tide station. Atlantic tides party

Tending tide gauge in intracoastal waterway.

Verifying predicted tides. Chart evaluation survey. Party off of PEIRCE

Verifying predicted tides. Chart evaluation survey. Party off of PEIRCE

Cleaning the tide staff. Atlantic tides party

Water level gauge at Lake Mead. Party of Emmett Sheridan

Hualapai Wash water level gauge. Party of Emmett Sheridan

Wiredrag diagram. The basic principle is to drag a wire attached to two vessels. If the wire encounters an obstruction it will come taut and form a "V"

Wiredrag - engine and guiding roller. Deck of contract sloop NENA A. ROWLAND. Wiredrag party of N. H. Heck

Wiredrag - arrangement of deck of guide boat. Deck of contract sloop NENA A. ROWLAND. Wiredrag party of N. H. Heck

Wiredrag - plotting table and instruments on guide boat. Deck of contract sloop NENA A. ROWLAND. Wiredrag party of N. H. Heck

Wiredrag - N. H. Heck watching the brake to stop reel. Reel stopped to attach floats and buoys to mark wire location. Deck of contract sloop NENA A. ROWLAND. Wiredrag party of N. H. Heck. Only known photograph of Nicholas Heck in the field

Diagram of obstructions discovered by wiredrag. Wiredrag party of J. H. Hawley

Wiredrag vessels in Massachusetts Bay party. Guide launch pilot; end launch Two Brothers; large tender at buoy. Wiredrag party of J. H. Hawley

Watching the wire coming in. Working in approaches to Boston Harbor. Wiredrag party of N. H. Heck

Stowage of wiredrag equipment. Working in approaches to Boston Harbor. Wiredrag party of N. H. Heck

Guide launch FORTUNA setting out the drag. Working in approaches to Boston Harbor. Wiredrag party of N. H. Heck

Taking up the drag on the EQUATOR. Wiredrag party of J. A. Daniels

Setting out the large buoy. Wiredrag party of J. A. Daniels

Wiredrag problems - buoys on wire crushed by being pulled under by tides. Wiredrag party of J. A. Daniels

Wiredrag problems - removing kelp from the wire.

Setting a floating signal to help navigate wiredrag operations. Wiredrag party of J. H. Hawley

Contract wiredrag launch TWILIGHT. First view without wiredrag gear - second with wiredrag gear installed. Semaphore signalling device installed on second picture

Wiredrag contract launch ROOSEVELT. Drafting table and shelter for plotting sheet installed. Wiredrag party of A. Joachims

Wiredrag problems - buoys crushed by water pressure. Buoys carried under by strong tidal currents in the Race. Wiredrag party of R. P. Strough

End launch STANDARD equipped for wiredrag work. Wiredrag party of R. P. Strough

Setting out the drag from the guide launch PILOT. Wiredrag party of R. P. Strough

Guide launch PILOT showing drag gear. Wiredrag party of R. P. Strough

Setting out the drag and buoys from the guide launch. Note semaphore signaling device on stern. Wiredrag party of J. H. Hawley

Drowned forest discovered by wiredrag on Lake Washington. Pulling up a moderate size tree. Wiredrag party of N. H. Heck

Wiredrag using oar power. Note third boat at distant right. Wiredrag party off of SURVEYOR

Wiredrag hung up on obstruction at buoy no. 4. Note "V" of buoy path characteristic of obstruction discovery. Wiredrag party off of EXPLORER

Newspaper feature on wiredrag in Brooklyn Daily Eagle. Wiredrag party of B. H. Rigg

Drag tester - Mate Franz Okeson on right. Wiredrag party of B. H. Rigg