Page 230 - The ROV Manual - A User Guide for Remotely Operated Vehicles 2nd edition

• Do not apply grease excessively. A thin coat is needed for lubricity only. Grease has no shear strength and does not seal. Too much grease can prevent the O-ring from moving into its optimum position and can even cause hydraulic fracturing of epoxy parts.
• Use only food grade silicone spray. Non-food grade has corrosive volatile propellants that cannot escape a sealed connector pair and can result in “dezincification of brass.”
• Keep spares of critical connectors on hand.
• Do not use petroleum-based products, like WD-40, on rubber cables and connectors.
• Any accumulation of sand or mud in the female contact should be removed by flushing with
clean fresh water. Failure to do so could result in splaying of the contact and damage to the
O-ring seal.
• Ensure that there are no angular loads on the bulkhead connector as this is a sure way to destroy
a connector.
8.11 Summary
Underwater cables and connectors provide system flexibility, ease of service, and other design advantages for undersea equipment including ROVs. The primary purpose of underwater cables and connectors is to provide a conductive path without leakage in a pressure-resistant or pressure- tolerant package. They allow simple system reconfiguration.
A mated connector pair forms a unique small pressure case. All pressure case design criteria apply. A bulkhead connector or penetrator becomes a mechanical part of a pressure hull, and it should be looked at critically.
EM cable design is driven by the specific end-user application. Design criteria include power, data, and strength.
Test EM cables both electrically and mechanically simulating the application field conditions. Use field terminations whenever possible. Exercise caution when interpreting results.
Feel free to discuss your requirements with the manufacturer and experience improved opera- tional effectiveness by using the proper cable designed for your application.
Bibliography
1. Parker O-Ring Handbook (ORD-5700) is available as a free download at ,http://www. parker.com.. Enter “ORD-5700” in the Search box. The Handbook provides details on numerous groove designs, back-up rings, elastomer selection, machining tolerances and finishes, installation procedures, and everything else you might have ever wondered about O-rings. There are generic O-ring groove design charts, and information on how to finesse a design for a particular applica- tion. Parker is never wrong. Ever.
2. Bash, J., Ed., Handbook of Oceanographic Winch, Wire and Cable Technology, third ed., is available as a free download at ,http://www.unols.org/publications/winch_wire_hand- book__3rd_ed/index.html..
Bibliography 219