By James Lapenta
Most people need to add weight when diving. That’s just a fact of the activity. How that weight is added can take several forms. Whether in the form of lead on a belt or in integrated pockets, by using steel cylinders instead of aluminum, or with a BC that doesn’t have a lot of unnecessary padding and makes use of a steel or aluminum plate.
As important as the weight itself is how that load is distributed. The distribution includes placement and, in some cases, making use of two or more systems to ensure safety, comfort, and proper trim. There is no reliable way to estimate how much weight someone needs or where to put it. The only way to ensure adequate weighting and placement is to get in the water. Anyone who says differently is a magician or a liar.
There are “rules of thumb” to be found in just about every training program. Ten percent of body weight plus xx for a 5mm suit, 7mm suit, etc. is one that seems to crop up from time to time. All of these are no more than a WAG. For those who don’t know the term, a WAG is a Wild Assed Guess. Once in a great while, an instructor and diver will get very lucky, and one of these will come very close to working. The problem is that too many divers and instructors latch onto this as proof that the method works and use it for everyone.
This is why you will often see students where this method was used, yoyoing through the water, having difficulty maintaining trim, plowing up the bottom, or racing to the surface in an uncontrolled ascent. Managing the load means none of this has to happen. That management starts with an instructor that understands proper weighting and trim, while not being too lazy or rushed to do it.
Working on getting your weights correct is not difficult or time-consuming. With the proper instructor or mentor and a pool or pool-like conditions, anyone can get their weighting and trim very close to ideal in a couple of hours. Those who have been told that proper weighting and weight distribution takes many dives and days or even weeks or practice have been misled. Either intentionally or just because the instructor is unable or unwilling to do the job right.
A recreational diver should never be overweighted to the point that they can’t swim their gear up from depth in the event their BC fails. This is known as diving a balanced rig. There is a misconception that diving a balanced rig does not allow for ditchable lead. This is not the case. It merely means that the diver is only carrying the amount of weight necessary. They should not be planted on the bottom to keep control over them as some instructors seem to feel.
Too much lead increases the chance of a runaway ascent as the diver rises in the water column. Boyle’s Law explains how this happens. No diver should accept being handed an amount of lead and hear something along the lines of “this should be enough to get the job done” or other such nonsense. A proper class will do frequent checks during the pool sessions and on checkouts between dives to ensure the diver only carries the amount of lead they actually need. Not what is convenient for the instructor.
Once you have the correct amount of weight, it’s time to decide where it should go. I feel that once you get to a certain amount, ballast should be spread out between two or more systems. Not all in one device such as a BC or weight belt.
The loss of any portion of it should not result in a rapid ascent. For myself, once I get above 10 lbs, I put some of it on a belt with individual pockets, some in the form of steel cylinders, a portion in pockets on the cam bands if diving a single tank or even bolted to the plate of my backplate and wing. Since I’m carrying only what I need, on the off chance I do need to drop lead to get or stay positive, I can do it in small increments. I could still jettison my belt and would if absolutely necessary, but I’m not worried about an accidental loss causing a problem.
The benefit of distribution also allows you to move the lead to the places it’s needed. The most significant air spaces in the body are the lungs. Many divers need lead over them to help achieve horizontal trim. Sadly this seems to be lost on the majority of BC manufacturers when deciding where to put “trim pockets.” A word to BC designers – the kidney area is not where the lungs are located. By utilizing a steel plate or pockets on the upper cam band, along with moving the cylinder up, divers can get weight over the lungs that will help them to stay horizontal.
Moving lead up on the body also helps to counter what I call “heavy leg syndrome” that is the result of the large dense muscles of the legs, lack of fat on them, and to a degree – heavy fins. When you combine these, the result is often that the diver is swimming at a 45-degree head – up angle. Getting some of the added ballast higher up will aid in countering this. It still does not excuse poor technique, but it will help.
I go into detail on the way I weight students in SCUBA: A Practical Guide for the New Diver in a way that an instructor is not needed for the competent diver to do it. It takes a buddy pair willing to pay attention to detail and a little time. Not to say that an instructor won’t speed up the process. A good one will. A bad one will result in frustration. You can’t teach what you don’t know or practice yourself.
About James Lapenta
James Lapenta from Canonsburg, Pennsylvania, a Diver, dive Instructor, Author and owner of UDM Aquatic Services has been diving since 2004.
He is a Scuba Educators Instructor # 204, SDI/TDI Instructor # 16810, CMAS 2 Star Instructor # USAF0012000204
For more on basic skills and education pick up a copy of either of my books