When working with ROV equipment, preventing equipment downtime is crucial for a successful subsea project. This blog will highlight a few standard procedures and tips to keep your ROV cables operational at all times.
Although we trust that you and your team rely on years of experience, a fresh perspective on extending the lifetime of your subsea equipment makes sure you stay operational as long as possible – without having to make large investments.
Shipping, storing and unpacking your subsea equipment
Proper handling of your ROV equipment starts as soon as the ROV cable is shipped to your facilities or vessel. Minimizing downtime begins before the ROV equipment is deployed; store your ROV cable with care when it’s not being used. A couple of tips for shipping and storing your ROV equipment:
- Always transport and store drums upright. The drum is not designed to be tipped as it may cause the flange to break.
- The drum should be battened during transport to protect the cable and hoses. ROV cables stored for long periods should also be battened.
- When storing subsea equipment, ensure the temperature is between –20°C and +60°C.
- To prevent the outer layer from becoming brittle due to exposure to sun and salty environments, ROV cables must always be kept under a cover.
For a complete and thorough overview of shipping, storing and unpacking instructions, always make sure to consult your ROV cable manufacturer for documentation. After unpacking, you get to work with your subsea equipment. Even in the deployment stage, there are a lot of tips and tricks to give your ROV cable a longer lifespan and minimal downtime. Below we list the four most essential handling tips.
Tip 1: Do not exceed the ROV Cable’s bend radius
The first tip may seem obvious, but it is a very important one. Never go below the minimum bend radius!
Sharp and/or double bends are real ROV cable killers. Therefore, the cable should never be subjected to bend radii below the minimum recommended radius. During extreme bending the inner- / bedding sheath, outer sheath and subcomponents will be severely stressed and may be damaged.
Tip 2: Do not exceed the maximum workload of subsea equipment
In addition to the previous point, the ROV cable must never be loaded above the maximum workload. The ROV cable is constructed with a specific workload in mind; the material and components are designed accordingly. However, if you load the ROV cable with more weight, it stretches too much. Overstretch is a notorious cable killer.
Additionally, loops or kinks will eventually damage the ROV cable irreversibly, especially in combination with overstretching. When the cable is pulled or stretched, the loops will reduce in size until the cable bends to such a sharp angle it cannot recover. Therefore, the ROV cable must be straight without twists or loops for optimal life expectancy and minimal downtime.
Read more about stretching and rotating here
Tip 3: Prevent overheating of your ROV equipment
The following important tip has to do with temperature-related issues, often caused by cable length. Subsea ROV cables are manufactured to work underwater. Seawater will cool the cables while operating at full power. However, if the cable is too long, there will be a large segment left on the winch while operating at shallow depths. Operating the ROV at full power with multiple layers of cable wrapped around the winch can cause the cable to overheat. DeRegt calculates the heat generated on the winch with a verified thermal FEA model.
Overheating on the winch is an example of how vital the fit-for-purpose factor is. The function of the ROV cable is to operate at certain depths. Therefore, besides designing the cable for the maximum depth, it is also important to know the minimum operating depth in order to verify that the cable will not overheat.
Tip 4: Treat your subsea equipment like you treat your car
The last essential tip for handling your subsea equipment: ask for help if you have any doubts about the well-being of your subsea equipment!
This is no different from how you would handle other valuables, like your car. If something doesn't look like it should or you hear a distinctive noise, you don't ignore it. Instead, you take a picture and contact the garage to have your car checked out.
It would be best if you did the same thing with your subsea equipment. In the case of ROV equipment, you contact the supplier at hand instead of the garage.
Not every supplier deals with this similarly, but as a "strategic partner" DeRegt likes to go the extra mile. For example, we offer field service. One of our field engineers boards your vessel to fix the problem and minimize the downtime of your ROV cable.
The connection between lifespan, downtime and other design considerations
In this blog, various tips are discussed to ensure your ROV’s lifespan is as long as possible and downtime is kept to a minimum. Life expectancy and downtime are important design considerations when manufacturing an ROV cable.
Other important design considerations are Function, Power Distribution and Budget. All of these impact each other and the final design to great extent. Are you curious about the other important design considerations and their impact on your ROV Cable? Download our free Webinar On-Demand here:
With all other questions about your cabling needs, you can contact my colleagues or me here. Our experts are always happy to create a Custom Cable Design for your specific project or explain more about life expectancy, minimizing downtime and other design criteria for your optimal ROV Cable.
