Beer is heavy.
Five gallons of beer in a glass carboy is very heavy. At about 8.3 pounds per gallon, plus 10 to 15 pounds for the carboy, the total comes out north of 50 pounds.
Dropping a glass carboy full of beer would not be a fun experience. First there is the mess. Then there is the expense of ingredients, carboy, and the wasted time you spent brewing. And finally, there is the risk of severe personal injury. There are numerous horror stories on the internet about people cutting themselves on broken glass carboys.
Given all of that, it seems prudent to take some precautions. This is especially true since these heavy glass containers are often wet and slippery at the times they need to be moved.
Luckily there is a good, commonly-available, and inexpensive solution: the Brew Hauler. It is a carrying sling made of nylon webbing that gives you two perfect handles for securely lifting and carrying a full carboy. This is incredibly helpful when lifting it in and out of a chest freezer.
The only complaint I have with the design of the Brew Hauler is that it sags. (If you look closely at the picture from Austin Homebrew, they had to use tape to keep it in place.) I was never able to tighten the top strap enough so that it would stay on its own. Even if I were able to, I would have to redo it each time I moved it to a different size of carboy. I have to admit that this is a relatively minor complaint. However, when it sags, it makes it easier for the straps that support the bottom of the carboy to shift. This could result in the carboy slipping out from between those straps if care is not taken to realign them before lifting.
My solution was to add a bungee cord to the top strap. This keeps the brew hauler snugly in place around the carboy. The materials are simple. All you need is one 24" bungee cord and four hose clamps. Any style of hose clamp that is about the right size should work just fine.
I used Oetiker style clamps because I had them lying around. They are stainless steel, which means they won't rust if they get wet with spilled beer or condensation. They are rather permanent once crimped, and there are no sharp edges or protrusions that could get caught on something. One of the clamps and the crimping tool are pictured below.
Step 1: Cut the hooks off of the bungee cord. They are not necessary and would just be in the way. Then singe the ends of the nylon sheath around the bungee cord's core with a match or lighter. This is just to prevent the cut ends from fraying or unraveling.
Step 2: Clamp one end of the bungee cord to the non-adjustable side of the buckle on the top strap. See the picture below. I used two clamps, which may be overkill, but I am confident that the bungee cord isn't going anywhere.
Step 3: Pull the bungee cord through each of the loops on the handles and lower straps. This is just like putting a belt on through belt-loops.
Step 4: Clamp the other end of the bungee cord to the strap on the adjustable side of the buckle. The only semi-tricky part is to make sure that the bungee cord is placed correctly. With the bungee cord completely relaxed, there needs to be 3 to 4 inches of slack in the webbing between the two sets of clamps. This way, when the webbing is pulled tight, the bungee cord is forced to stretch and maintain tension.
This end also shouldn't be clamped too close to the buckle. There needs to be enough adjustment to pull the webbing tight around the smallest diameter carboy on which it will be used. As you can see below, I left a couple extra inches just in case. There are two clamps on this end as well; one is covered by the loop on the nylon strap. You can also see the singed end of the bungee cord in this picture.
For me, this has made a good product even better. I ended up buying and modifying a second Brew Hauler so that I have one for each carboy when doing two batches at the same time. It was annoying to remove the Brew Hauler from the carboy after it was in the chest freezer and then try to put it back on later when it was time to rack the beer. These are great things to have around, and I highly recommend getting a couple.