we're able to prevent accidents from occuring.
One of the most important skills in diving is learning how to be aware of your surroundings on a dive. When it comes to a hose failure, you might have small failures that are barely noticeable; or maybe a hose that decides to ‘split’ open. Both of these failures can cause a diver to be in a dangerous situation and possibly panic. Therefore, it is extremely important to prevent these situations from occurring.
This week, while I was brainstorming what to discuss, I decided to replace the hose on my regulator where I had a failure over the weekend. So, my reason for posting this article is over that personal failure I had on a low-pressure hose. Hose failures come in all varieties and styles: high-pressure leaks, low-pressure leaks, rubber cracking, crimp failures, bulging/cuts, splitting/fractures, and some mi-flex hoses might fray.
Before I go on too in-depth with my personal failure, I’d like to give a visual representation of the type of failures as stated above.
high pressure vs. low pressure
As the illustration below shows, the high-pressure hose on the left has a very small orifice compared to the low-pressure hose on the right. If a high-pressure hose is cut open, it will not drain the air as fast as a low-pressure hose. This confuses a lot of people because the high-pressure hose sees pressures up to 3500psi! Well, that small orifice only allows so much air to pass through at once. Even though the pressure is high, the flow of air is restricted. Low-pressure hoses (like 2nd stage hoses, octopus hoses, and inflator hoses) flow a LOT more air, even though the pressure is only 140psi~. This is why all hoses must be streamlined to prevent being cut underwater.
Leaks can occur where these hoses meet the 1st stage, 2nd stage, alternate air source, inflator, gauge, and spool (explained in-depth below).
Rubber cracking is the most common version of a hose failure. This is caused by poor care of a diver’s gear. For example: a diver that does not rinse the salt water off his/her dive gear after the day can run the risk of allowing the rubber to dry-rot. Just like all rubber products, if left in the sun for long periods of time, the UV rays can cause cracking. Simple cracking can be addressed early and hoses can be replaced. If not addressed in time, it can cause small leaks to occur all through the rubber and the possibility of tearing in half. During service, this is addressed to all of our customers.
Crimp failures are another common form of hose failure. This is when the crimps on either end of the low or high pressure hoses start to leak. This occurs with improper care of gear, rather if the crimps experience too much stress from pulling on hoses or improper rinsing. The only fix is to replace the hose. It is very important to have the correct length of hose to prevent this from happening.
bulging and/or cuts
The picture below shows a ‘cut’ or ‘tear’ in a standard rubber SCUBA hose. Sometimes the cuts are not deep enough to cause bulging. However, in this situation, once the 1st stage applies the intermediate pressure of 140psi~, the hose ‘flairs’ out and causes a ‘bulge’. This can be extremely dangerous and can sometimes lead to a rapid air loss (if it were to ‘pop’). Simple assessments and proper observation of a diver’s surroundings underwater can eliminate this from happening.
Just like the name suggests, a fracture is when the hose completely fails and splits into two. 90% of the time this occurs when the internals rot from the inside out. This is because a diver might not service their gear on time. This is not a very common form of hose failure but can be deadly at depths. The picture below is a hose that was from 2004 and hadn’t been serviced/checked out in years.
Mi-Flex hoses are made out of wrapped fibers that can come lose if not properly taken care of. This can happen if it is rubbed against something for a long period of time. Definitely replace these if they start fraying because they are pretty sharp and can get stuck in a finger through a glove. It has happened to me.
While a spool failure is not a hose failure, it can be wrongfully viewed as a crimp leak because the leak comes from the same general area. As illustrated below, the spool is an internal part to allow a gauge to spin freely on the hose for positioning. It has two tiny o-rings on it that can cause leaks. These are less than $10 and can be replaced easily. These are only on high-pressure hoses – if even used. I highly recommend purchasing a couple for a save-a-dive kit.
1st Stage O-Ring Failures
These o-ring failures also are sometimes misdiagnosed as a hose failure when actually it’s a 10 cents o-ring that failed. This o-ring is replaced during the annual or bi-annual 1st stage service and can easily be replaced by a diver. Grab a hand full of high-pressure and low-pressure o-rings for your save-a-dive kit!
Well, back to my story. As stated in the beginning: I had a hose failure last weekend. My hose fell along the ‘bulging/cut’ tier of failures. This is one of the more dangerous failures as it can cause rapid air loss. I was diving with some students in their Open Water certification class. One of my students spotted out that my hose was leaking near the end of our dive. Once we returned to the surface, I tied a knot in that hose so I knew it needed to be replaced and gave that student a thank you and a high-five for being aware of his surroundings! I’m unaware of when this occurred on our dive or if I missed it during my assessments. Either way, it is extremely important to watch your dive buddy at all times and make sure they understand the same thing.
As divers, we all know that a self-assessment check before we enter the water is very important. A quick glance at all your gear for cuts, tears, cracks, and leaks is a cheap way of insurance that can save an accident from happening.
Service it on time!
Simply following your service schedule will eliminate a lot of these failures from happening. Too often do we see divers that try and go over their service period by just a year. If a regulator is left in UV light for too long or saltwater dries inside/out of it just ONCE, it can cause one of these failures to take place. SCUBA Diving equipment is a life-support system and should be serviced in a manufacture’s recommended period.
The buddy check is the most important part of diving. This is our pre-dive check that our buddy will perform on our gear and we will perform on their gear. Treat your buddy inspection as if it was your own personal gear as dive gear is a life-support system. If you or your buddy missed an issue, – in this case, a cut or cracked hose, you are able to abort the dive or replace it with gear in your save-a-dive kit.
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