MECO Marine Sea Gard
Rudder Post Seal
The SEA-GARD provides an effective rudder post seal in abrasive, coastal waters. Wear materials are softer than those used in traditional mechanical seals, and permit the use of wide-radius seal faces. These easily tolerate severe eccentric rotation and permit wear to occur without compromising the seal.
• Elastomeric Drive Design Tolerates Shock Loads & Radial Eccentricity
• Will Not Open Up Like Packing
• Long Service Life
• Fully-Split Designs Facilitate Easy Installation & Rebuild
The wide seal face radius permits the Sea-Gard to function despite severe bearing wear which causes other seals to leak. Seal face loading is accomplished by an elastomeric drive: there are no metallic springs to corrode and fail. The soft elastomer buffers shock loads and maintains seal integrity under the roughest operational conditions. The fully-split Sea-Gard is user-friendly and simple to install. Seal faces can be freely handled. There are no gauge blocks, calibration rods or special shaft finishes required for installation. An accurate shaft measurement prior to purchase ensures proper calibration on assembly. Sea-Gard seals are available in sizes to fit every rudder post diameter, and various materials permit compact designs for installation in areas with minimal axial clearance.
Tug KENNEBEC and Captain Steve House, on the fogbound coast of Maine
The 45-foot harbor tug KENNEBEC, operated by Bath Iron Works Corporation, performs general waterfront maintenance duties at the Bath, Maine shipyard. Her duties include barge service and channel dredging, as well as service as the company's pilot boat. Ready to cast off at any moment, she is often called on for search and rescue operations.
Built in 1955 at Equitable Equipment Company Shipyard Division in New Orleans, KENNEBEC is powered by a Caterpillar 3408 diesel with a 3.5:1 reduction gear, developing 400 horsepower. Her rudder post was originally equipped with a conventional packing box. Although the box is located in the lazarette, well above waterline, this seal leaked profusely when the tug took a load.
Upon hearing of a locally-made, alternative seal, Captain Steve House, with BIW Facilities Division Area Supervisor Greg Bridgman, pursued acquisition and installation of the seal, in hopes of correcting the leakage problem.
A MECO-MARINE SEA-GARD seal, designed and manufactured for KENNEBEC by MECO Seal in Georgetown, Maine, was installed when the tug was reshafted during a periodic overhaul in May of 1994.
The SEA-GARD design is a double-faced, mechanical seal, which features a flexible, elastomer drive system and wide-radius seal faces, and accommodates significant angular and radial misalignment of the shaft. The seal is fully split, and can be rebuilt when needed with split replacement parts. Several adjusting shims are incorporated into the seal: as the sacrificial seal faces wear with time, the seal can be quickly returned to normal calibration by the removal of a shim.
Following a ten-month "run-in" period, slight leakage was noted, and MECO-Marine was called to inspect and service the seal in April of 1995. To the amusement of traffic crossing the Kennebec River on U.S. Route One, several minutes of hard maneuvering at high speed were required to induce leakage. In a half-hour maintenance session, an adjusting shim was removed and the seal reassembled.
According to Capt. House, the seal has functioned flawlessly since. An inspection by MECO-Marine personnel in February of 1996 showed no outwardly-apparent wear of the sacrificial parts, and the seal was photographed and left assembled.
Photographs by Martha Oatway
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