A Boater's Guide to Carabiners
Carabiners are such an ubiquitous and important fundamental of boating life, unfortunately in the boating world we spend far too little time discussing their use and implementation. Many boaters climb as well and it is important to note that although rope work, anchors, fundamentals of force, and implementation of equipment has many parallels; applying every principal of climbing to boating paints an inaccurate picture of what the focus is on the water.
Parts of a Carabiner
This makes the whole system work. There are 2 major styles of carabiner gates locking and non-locking. There are a couple major styles of non-locking carabiners; wire gate and solid gate.
Unlike climbing where non locking carabiners are often used, in boating a non-locking carabiner is the devil. Given the number of impacts that occur on the river, the constantly shifting gear, and sometimes flying people; there is no place on a boat for a non-locking demon carabiner. The potential to fly into a carabiner during a surf or a flip, then getting your PFD caught in it, only to hold you underwater, or against a rock is just too much of a risk.
Locking carabiners are exponentially more safe, effective, and common amongst boaters. There are 2 major styles of locking carabiner that are available (they go by many names): manual locking and auto locking.
Auto locking carabiners are very common; however they tend to be expensive. Most boaters opt for only one of these carabiners. It is most commonly seen attached to a flip line since that item is used on a constant basis by rafters. With the frequency that the flip line is used most boaters prefer to use something quick and convenient that does not require a boater to fiddle with both hands.
The manual locking carabiner is the most common type of carabiner you will find amongst river folk. The biggest advantages are that this carabiner is cheap, gets the job done, and will not just flop open. Most climbers will advocate for lighter gear since they are constantly working against gravity. River folk rarely have to worry about whether a couple of ounces in carabiners will slow them down since the whole goal is to go down.
One critical downside to the gate function of carabiners is grime. Rivers contain sediment that works it way into the smallest places including the precious gates on your carabiners. We recommend, at a minimum, once a month double checking the function of your carabiners, cleaning grime and lubricating the gates. Ideally you will be doing a cursory check of your gear before and after each trip to ensure proper function.
There is one other new style to note and that is the magnetic locking carabiner. This is also not a recommended type for the following reasons. 1. Magnets can easy pop open under the sudden forces encountered in boating. 2. if it is a ferrous magnet it will rust and degrade. 3. Magnets will suck up tons of magnetic sediment from the river and it will impair their function.
The spine is the workhorse of the carabiner. This section bears the brunt of the load. Manufacturers tend to strip material out of this section when they are attempting to reduce weight. It is worth taking the time to look into beefier carabiners. Pulling a wrapped boat of any kind off of rocks or out of trees places a tremendous amount of stress on your gear. Carabiners are exposed to a lot of force through these stresses so check carefully for cracks during your inspections and consider retiring them after high stress work (see strength rating below)
The nose comes in a couple basic types the keyhole style and the hook style. The key hole has become the new dominant style of nose. A 2015 study on carabiner tensile strength showed in interesting pattern of hook nose carabiners failing along the spine, while keyhole carabiners experienced "keyhole blowout" in the gate. This interesting point of note is that the keyhole locking carabiners also showed increased elasticity thus allowing the carabiner to hold longer under constant stress while deforming the metal.
The major axis is where most of the force to the carabiner will be applied.
Users should take care to avoid loading carabiners across this axis at all costs. The strength rating across this axis is typically 1/3 of the major axis' KN rating.
This is my ol' pappy's classic biner. Tough tested and well respected. These carabiners unfortunately often find themselves in the repertoire of boaters. Old school climbers and boaters attempt to repurpose their gear or gift it to new young guides. The gesture is nice, but it is sort of akin to using previously used toilet paper. Thanks but no thanks.
There is a lot of fancy new carabiner technology out there, but this one is the boater's go to. Asymmetric carabiners may be where it is at for climbing, but as a boater it is not weight or fancy features that are the most concern. Low profile and ease of use are what we thrive on. In your typical river rescue scenario you will have numerous people with different levels of experience chiming in about boats wrapped, people swimming, lines in the water, why Brian is 30 feet up in a tree, and how that girl on the wrapped boat had her hair catch on fire...also has anyone seen that random kayaker we picked up at put in. This picture may not be completely representative of a typical river rescue, but it is represented of what happens on scene. it is a chaotic mess and you don't need to throw pear-shaped magnetic locking carabiners into the mix while you are working with ropes. Just keep it simple.
This is a pretty cool thing for keeping your ATC in place while belaying...one problem. You are not belaying anyone and nobody has an ATC. Unless you are doing some serious expedition boating through some sketch high altitude creeks and you need to belay it is best to leave this carabiner on your climbing rack. Like my ol' pappy used to say "Boy, pears are for eat'n".
This nifty carabiner style is renown throughout the climbing world. I have a few. They are great for belaying and on my alpine rack... but they work really well on a flip line for extra leverage or having a wide gate to quickly clip on to things. This is about as far as it goes though. It is a good piece of equipment to have one of on a flip line for fast one handed use especially with an auto locking carabiner. Also, auto locking designs generally are pretty asymmetric.
Materials and Weight
Steel - These monster strength carabiners are great for industrial use, but they really have no place on the river. With all the water their propensity to rust and degrade will make this carabiner last on your list.
Aluminum - This is your go to. These carabiners don't rust, but they can corrode if left in wet gear for too long and not cleaned. This will eventually weaken them to the point of not being usable.
How much carabiner do I need? This can be a tricky question. First we need to look at the difference between industrial vs. recreational carabiners.
Industrial carabiners are rated for a load with the breaking point being up to twice the max working load. These carabiners are used in applications from towing and aviation, to mining and shipping. Recreational carabiners are designed to break at the listed load rating. This creates a very different precedent. The margin for error is a lot lower, but it is not like we are trying to lift a Humvee with a sky crane.
Now it is time for the physics lesson. It is important to understand what a kilonewton of force is. The basic equation is Force = mass x acceleration. This means that force is a dynamic rating, not static weight. Generally under the force of gravity 1 kilonewton = ~225 lbs.
Thus the carabiner pictured above would break under a static load of approximately 6975 lbs. This is important to note since a wrapped boat can easily fill up with 500 gallons of water. the water alone in a wrapped boat could be at or nearly 4000 lbs. Add any gear in the boat, the boat itself, and the force of pulling against the river and you could easily get a standard z-rig to the point of blowing out carabiners and sending shrapnel into your well-meaning meaning buddies assisting with a wrap.
What our teams use
Rafting Magazine expedition teams typically prefer to have 2 manual locking D carabiners available per person on the trip. In most settings this will allow them to have several working carabiners and a couple spares if the trip is big enough. They typically use carabiners with a minimum rating of 25 KN and preferably 31 KN. They feel that this provides a safe margin of error given the worst wraps imaginable. Additionally they bring along 1 flip line with an auto locking carabiner each.
In any case this article is no replacement for training and certification with a skilled whitewater professional. With all equipment you should carefully evaluate the needs of your trip, your skills, your boating group, and any other factors that might play into your next proposed river trip. Boating safely and wisely falls to your own discretion and due diligence.