Maintenance & REPAIR Take Care of Your Umbilicals And They’ll Take Care of You

By Chris Gabel of Ocean Eye, Inc.

reetings fellow divers. This issue, I thought that an appropriate subject Gwould be umbilicals. If you had the fortunate experience to attend Underwater Intervention 2008 in New Orleans (for more on the 2009 event, visit underwaterinterven- tion.com), you would have seen a plethora of choices when it comes to umbilical design. Our goal here is to cover some of the design aspects of the present day commercial umbili- cal and go over some basic maintenance.

UMBILICALS 101 First, I think it would be prudent to go back to basics. According to the US Navy’s umbilical manual, which is available for download at www.supsalv.org, the um- bilicals consist of at least a .375-inch inner diamter (ID) gas hose, a .25-inch ID pneumofathometer hose, a communica- tions cable, and a strengthening member. It also mentions that the communications cable and strengthening member may be a single integrated unit. Now some of you out there may be think- ing about the new .25-inch hose that’s being talked about and tested for shallower water diving. As of this writing, I have not heard that the .25-inch type is being approved for civilian use, although there are undoubt- edly people testing that configuration out for themselves. There are currently two configurations for the .25-inch hose that I know of. One consists of just using the .25-inch breathing hose for shallow depths and the other uses a small air cylinder with an attached first stage. That assembly is attached directly to . For more information or questions on the .25-inch breathing hose, a good reference would be to contact Mike Ward at Dive Lab. For this article, I am going to refer to the cur- rent .375-inch standard.

YOU SAY TOMATO... There are several different ways that the umbilicals can be physically put together. The first is the straight, or non-twisted, umbilical. Umbilical spool from Umbilicals International. This is a common set up where the pneumo 16 www.adc-int.org • www.underwater.com May•June 2008 Diving Equipment & Maintenance line, communication line, breathing air expensive, but if you’re planning on div- line, and strengthening member are laid ing contaminated water, then this is more out and taped together. The strengthen- of the configuration for you. ing member is assembled so that strain is on the strengthening member line and FITTINGS not on the rest of the assembly. The fittings come in two flavors. The Taping occurs every 18 to 24 inches. tried and true brass fittings are the most The US Navy suggests using Polyken or common, at least on the East coast. The (Below) At right is a standard twisted umbilical. duct tape. You can also use color codes other option is stainless steel. The price On the left is a twisted setup with an anti-foul, if you wish. That way topside can more of raw materials has made stainless steel abrasion-resistant outer guard. readily tell the length of the umbilical one of the big buzzwords in the industry. over the side. The price of stainless and brass has be- Another set up is the twisted umbili- come close to identical, therefore making cal. This is where all of your umbilical stainless a viable alternative. members are twisted to create one unit. You also have the option of using This is more common on commercially “reusable” fittings. Although the theory manufactured umbilicals. of reusable fittings is sound, I’ve heard There are also variations on the mixed reviews in practice. You need twisted theme, such as a twisted umbili- to use your own best judgment on the cal with an anti-foul, abrasion-resistant question of single-use versus multi-use guard. One design looks a lot like the old fittings. Chinese finger torture toy. It consists of You should always visually check your a cross weave pattern of material. This fitting before and after each dive, as well material can run the entire length of um- as having them pull-tested at least annu- bilical or be limited to 50 or so feet from ally. The US Navy describes their test as: the diver to topside. “Using appropriate rigging components, Another variation has all of the um- attach the hose to a lifting device and to a bilical members encased. In this instance, 200-pound dead .” the entire umbilical is encased in a flex- ible material that will get cut, scraped, or HOW TO INSPECT IT chemically attacked first before sacrific- Like your tires or anything else made Stainless-steel fittings ing the internal members. It’s a bit more of rubber or rubber-like material, there is

18 www.adc-int.org • www.underwater.com May•June 2008 Diving Equipment & Maintenance This entire umbilical is encased in a flexible material that will protect the internal components from getting cut, scraped, or chemically attacked. This is the setup to use for .

a finite life expectancy. The US Navy states are not your friends! Run the Simple Green and water solu- a maximum umbilical life of 12 years. That For you tenders out there, zapping your tion through the air line for a while. When number is a guideline and not gospel. diver is not for fun and sport. Divers, treat- you think it’s clean, use the same process in There are a lot of variables that can ing your tender to a cocktail now and then the second can, but that should only contain determine the life of the umbilical. For can help avoid submerged discomfort, as clean potable water. This step washes the instance, exposure to chemicals can be a well. Make sure that all power lines are in detergent and water mixture out, so the air factor in the life of the materials that make good working condition and free from deep line should be allowed to drain outside the up the umbilical. cuts, abrasions, and defects. Make sure that can. Then, voilá, you have a much cleaner A pre-dive visual inspection is always the diver end is waterproof and secured air line. The same process can be used on your friend. You should inspect the umbili- properly. your pneumofathometer. cal for damage, bulges, swelling, cuts, and abrasions. If you think something doesn’t HOW TO CLEAN IT ANNUAL PULL & TESTS look right, then the equipment should be I’m not sure how many of you out there Your umbilical needs to be inspected sidelined until further inspection can be clean your umbilicals at least once a year. annually. What does that mean exactly? completed. I’ve seen that some organizations consider Well, that means that the umbilical should You should have your umbilicals pres- cleaning the umbilical blowing the hose be pressure tested to 1.5 times the working sure checked at least annually. I say annu- down. That, my friends, is not a thorough pressure. That also means that the fitting ally for any of the major inspections, but cleaning. It’s getting most of the inspects should be pull-tested, preferably using a that also depends on use. Some commercial and particulate matter out, but not cleaning 200-pound dead weight. outfits should have their umbilicals in- the inside from nastiness such as oils. Also, the umbilical should be cleaned spected quarterly – or more often than that Basically, you can make a great cleaning and thoroughly visually inspected. I would – depending on application and frequency system consisting of a couple of garbage have the annual inspection completed by of use. Again, this is a matter of personal cans (clean and unused) and a submers- trained professionals. That may be someone judgment. ible pump from the hardware store. You’re on your staff or a technician at a reputable Any electrical lines (for example com- going to be running some water through it, service center. After all, munications cable, welding line, light and not putting out a fire, so it doesn’t need to it’s your life depending on the rubber tube camera cables, etc.) must be waterproof. be more powerful than a decent steady flow. to the surface. That translates to true underwater cable My suggestion would be to take one can I would like to thank Erich Vargas of with appropriately installed waterproof and put in fresh water mixed with a mild Umbilicals International for some of the ends. detergent such as Simple Green. Put the pictures used in this article. Remember, I have to say it like that because of some umbilical in the can, attaching one end to dive safe. UW of the rigs that I’ve seen out there. A Wal- the pump. The other end can either be set Email your commercial diving equip- Mart lamp cord with liquid tape doesn’t inside the can or allowed to drain, your ment maintenance or repair questions to count. Be smart: duct tape and tractor lights choice. Chris at [email protected]. 20 www.adc-int.org • www.underwater.com May•June 2008