Lock Gates Research Articles

Salinity-temperature profiles in the Panama Canal Locks

In discussions concerning the possible construction of a Panama sea-level canal it has been assumed that Gatun Lake, part of the present canal, acts as a fresh-water barrier to the migration of marine animals from either end of the Canal to the other. Methodical documentary salinity determinations have not been made previously, and only a few surface salinity observations have been recorded. Determinations of salinity-temperature profiles made in spring and fall, 1972, show essentially freshwater to be present from Miraflores Lake, through the Pedro Miguel Locks, through Gatun Lake, to, and including, the upper chambers of the Gatun Locks. With the exception of those of the lower chamber of the Miraflores Locks, the profiles indicate homogeneity and thorough vertical mixing of all water masses in the lock systems and lakes of the canal. Homogeneity of the water in the lock chambers is thought to be due to turbulence during filling of the chambers, to the “piston-effect” of large ships moving into the chambers, to the action of ships' propellers, and to density currents established as the lock gates are opened. Water in the approach channel at the Pacific end appears to be more homogeneous than that at the Atlantic end. The Panama Canal does, in fact, constitute a fresh-water barrier to the migration of the stenohaline marine biota of the Pacific and Atlantic Oceans.

In the IAHR National Committee of the Soviet Union Seminar of the IAHR Section for Lock Gates

In the IAHR National Committee of the Soviet Union Seminar of the IAHR Section for Lock Gates

Closure to “Navigation Locks: Navigation Lock Gates and Valves”

Closure to “Navigation Locks: Navigation Lock Gates and Valves”

Discussion of “Navigation Locks: Navigation Lock Gates and Valves”

Discussion of “Navigation Locks: Navigation Lock Gates and Valves”

Navigation Locks: Navigation Lock Gates and Valves

Gates and valves for navigation locks are classified according to function as culvert valves, lock gates, or emergency closure gates. Model studies for McNary, Ice Harbor, Walter F. George, New Poe, and Hold locks have helped develop details of tainter valve design that show promise of satisfactory performance. Operational experience at several new locks reveals weaknesses of seal and trunnion anchorage design, and emphasizes the need for valve synchronization at moderate to high head locks. Miter lock gates have given good service over the years, but several new high lift locks are using vertical lift gates. The need for emergency closure gates must be determined for each lock individually and is best satisfied by vertical lift or submerged tainter gates.

NEWS OF INDUSTRY

Vinyl Coating System for St. Lawrence Seaway. A coating system based on vinyl resins was specified by the St. Lawrence Seaway Authority for all submerged and semi‐submerged structures in the Canadian section of the seaway. The vinyl‐based coating has been applied to all lock gates, bulkheads and tainter valves, and it is believed to be the largest vinyl protective‐coating application yet undertaken in Canada. Union Carbide vinyl resins were used for the system. The Authority's minimum specifications were:

Metallizing for Corrosion Prevention

Abstract Problems and techniques connected with the spraying of molten metal on iron and steel to prevent corrosion are surveyed, including surface preparation, bonding coat, organic sealers and the relative merits of the various metals sprayed. Characteristics of zinc and aluminum coatings are discussed and recommendations are made for selection vs. environment anticipated. A list of recommendations for specific applications includes ship's hulls, oil tanker interiors, fresh water tanks, marine atmospheric exposures, railroad bridges, steel piling, industrial atmospheres, exhaust stacks and mufflers and river lock gates.

ON THE STRAIN TO WHICH LOCK GATES ARE SUBJECTED. (INCLUDING PLATE).

ON THE STRAIN TO WHICH LOCK GATES ARE SUBJECTED. (INCLUDING PLATE).