Technical writing assignment specification: Write a step-by-step side scan sonar cable termination procedure which includes all the information that might be needed by a trainee engineer to immediately start repairing a cable and be able to complete their work in a safe manner.
The author of this procedure has made every effort to document all the information accurately and completely according to his own offshore experience and in compliance with manufacturers’ manuals and HSE policies. However, the author assumes no liability for any errors or damages that may result from the use of this procedure.
For the purpose of this technical writing sample (which is what this document really is — a technical writing sample by Russian Oil & Gas Translation Services and by no means a survey company approved procedure) and in order to keep in compliance with non-disclosure policies, no particular side scan sonar system manufacturers or trademarks are mentioned herein. In addition, since copying, reprinting, or otherwise disclosing any figures and specifications contained in manufacturers’ equipment manuals is strictly prohibited, no such figures or specifications are presented in this procedure.
Purpose of This Procedure
The purpose of this procedure is to provide trainee geophysical survey engineers with step-by-step instructions on terminating a damaged side scan sonar cable in a safe manner.
Health, Safety, and Environment (HSE)
All personnel involved in the side scan sonar cable termination described in this procedure shall read and understand the HSE warnings and recommendations provided below.
During the side scan sonar cable termination process, the personnel involved in the work have a risk of being exposed to:
- extremely high voltages
- high temperatures
- chemically aggressive and highly flammable substances
- sharp tools
All personnel involved in the below described work onboard a vessel, shall at all times wear Personal Protective Equipment (PPE) including but not limited to:
- hard hat
- safety boots
- safety goggles
- safety gloves
- life jacket when working offshore
High voltages that can cause injury or death are present in the side scan sonar system. Therefore, extreme care should be taken when handling the towfish and the cable.
Prior to testing the cable with the Megger, ensure that this cable is DISCONNECTED from the topside processor, otherwise irreparable damage will be caused to the topside processor and severe injuries to personnel.
Never leave the electrical tester and power tools connected to the mains supply when not in use.
A power tool or electrical tester should not be used if any part of it is damaged.
Using heat guns and soldering irons involves the risk of exposure to high temperatures that can cause severe burns. Caution should be taken when working with these types of appliances.
Chemically Aggressive and Flammable Substances
Adhesive compounds used in the process of cable termination are easily flammable and chemically aggressive. Ensure that relevant COSHH regulations and fire safety precautions are complied with at all times when working with these substances. Always wear safety goggles as contact of these substances with eyes will result in serious eye injuries.
Hacksaws, grinders, knives, and cutters can cause injuries. Be careful and always wear protective gloves when using these tools.
In accordance with offshore HSE policies, it is prohibited to carry and use any fixed-blade knives onboard survey vessels. However, it is allowed to use safety knives.
First of all, find the cable drawings — both end views — in the relevant manufacturer’s manual for this particular model of the side scan sonar towfish. Do not start any work on the cable without having these drawings at hand.
Tools and Materials Needed
- hacksaw or grinder
- cable stripper, safety knife, or cutters
- self-amalgamating rubber tape
- heavy-duty electrical tape such as Scotch® 3M Super 88
- Fluke® multimeter
- Megger® electrical tester
- soldering iron
- heat gun
- heat shrink sleeves (2 thin + 1 thick)
- Scotchcast™ compound
- SWITCH OFF the side scan sonar system.
- DISCONNECT the cable from the topside processor.
- Inform the bridge officer of the number of personnel on the back deck and the task to be performed prior to entry onto the back deck.
- Pay out enough cable to be able to take its end to the workshop, gun shack, or wet lab.
- Put the cable in the vice and cut the damaged part of the cable off.
NOTE: You might be required to get a hot-work permit from the bridge if you choose to use a grinder for that.
- Get a new pigtail ready.
- Check the layout of pins and sockets shown in the drawing in the manufacturer’s manual.
- Not all of the existing wires are needed in the cable; however, DO NOT cut those spare ones off as they will come in handy for providing extra strength to this part of the cable, so for the time of soldering just bend them to keep them out of the way.
- Strip the required wires on both ends, preferably using a cable stripper rather than a knife. See your company’s HSE manuals regarding knife policies.
- Check the new pigtail using the multimeter in the continuity beeper mode.
- Prior to soldering the wires, do not forget to put the heat shrinks on first — a thick one for the entire cable and 2 thin ones for the wires to be soldered.
- Do not put one of the thin heat shrinks on the shield wire; otherwise, it will shrink before time due to the heat from the soldering iron. Put it on the insulated end instead.
- Solder the wires.
- Seal the two thin heat shrinks up using the heat gun.
- Put 1 layer of self-amalgamating tape + 1 layer of Scotch-Kote compound on each one of the newly soldered wires.
- Bend the spare wires back — they will provide some extra strength to this weak part of the cable.
- Take two tests of the connection:
- First, test it using the Megger electrical tester. Before connecting the tester clamps to the cable, double check that the cable is DISCONNECTED from the topside processing unit, otherwise this test will damage the topside unit beyond repair. Before applying the Megger voltage, see the side scan sonar system manufacturer’s manual to check what voltage you need to apply for testing this particular side scan sonar system.
- After that, test the connection by connecting the cable to the towfish. Do not forget to connect the cable back to the topside processor before that. Carry out a rub test.
- Disconnect the cable from the topside processor.
- Put 2 layers of self-amalgamating rubber tape and 2 layers of electrical tape on the cable (on both wires at once now) applying Scotch-Kote between each of these layers: rubber — Scotch-Kote — electrical tape — Scotch-Kote — rubber — Scotch-Kote — electrical tape — Scotch-Kote.
- Pull the big heat shrink on.
- Two options:
- seal the big heat shrink using the heat gun starting from the center and going sideways, then put a small amount of electrical tape on its sides; or
- seal the big heat shrink using the heat gun only on one side (on the deck side), use some electrical tape to strengthen this part, hang the cable vertically using a rope, pour the Scotchcast compound in, wait for 8 hours, then seal the heat shrink sleeve up with the heat gun.
- The cable is ready for use.
- your side scan sonar system manufacturer’s manual and wiring diagram
- your survey vessel’s HSE manuals and procedures
- risk assessment (RA) plans
- toolbox talk (TBT) forms
Technical writing sample.
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