Knives are used for cutting. Cutting can be categorized as slicing, chopping, gouging, and chipping. Slicing includes chores such as opening food packages and cutting line, chopping includes cutting through branches and cutting steps in snow and ice, gouging is using the point to remove material using a prying motion, and chipping is using the point to chop.
SAR knives are predominately used for slicing. This is why I have been allowing any knife to qualify during orientations. A very small knife (one to two inch blade) can do most of the SAR slicing chores. It can't realistically do any chopping (too light), gouging (too weak), or chipping (too light and too weak). It will handle 95% of all cutting tasks that we are likely to encounter on a mission but it might be a little inappropriate for tasks such as cutting through a climbing rope.
A larger folding knife with a three to four inch blade is ideal to accomplish all of the SAR slicing functions. I like a knife that has a single blade at least three inches long, has an edge that includes a small serrated section combined with a conventional edge, has some belly (curve) in the conventional edge, and has a sharp point. A light-weight synthetic handle is a plus and a locking blade for safety is a must. Features such as clips and lanyard holes are up to individual taste. The blade steel should be a cutlery-grade steel such as 440 stainless or one of the exotic alloys such as AUS-34. Ceramic blade knives should be avoided as they are too brittle to be dependable. You can purchase a quality knife of this type for $20-$50. If you want a cheaper knife, handyman knifes with these characteristics can be found in building supply stores for $10-$20. Knives that cost under $10 may be suitable but should be carefully selected for quality.
Looking back on my SAR experience, all of my cutting tasks have been handled using one of my single-bladed folding knives. On the other hand, I carry 3-4 knives on SAR missions. The primary knives that I carry are a Benchmade Ascent folding knife and a Victorinox Clasic Swiss Army Knife. These are the same knives I carry in my everyday activities. The Ascent has a three-inch AUS-34 blade with an epoxy coating for weather resistance. It has a hole in the blade for one-handed opening and a pocket clip. The Classic does have a small blade, which is great for trimming nails and cutting line, but I find that the scissors and tweezers are the tools I use on the Classic most. These two knives are the only knives I have needed on SAR missions. I also carry two non-folding knives on SAR missions. One is a CRK Straight KISS that I bought at ESCAPE two years ago. It is intended as a back-up to my Ascent and has never been used but is light enough to throw in the pack and forget it until it is needed. The other knife is a Cold Steel SRK with an epoxy coated six-inch blade.
Before I go on let's discuss the characteristics that a SAR straight knife (non-folding) should have. Personally, I am a fan of straight knives. Straight knives offer many advantages such as ease of use (they are always ready to cut without reconfiguring such as un-folding), strength, and durability. They are clearly the choice for some of the tougher SAR jobs such as chopping branches and small trees to make expedient items such as splints and chopping steps in snow and ice. Larger knives are examples of SAR tools that you might never use but will be glad that you have it should the need arise. I am not advocating that everyone carry a larger straight knife on missions. This class of SAR knives is of limited use on normal missions and should only be carried by someone who is willing to carry a little extra weight "just in case". If you do choose to carry a large knife to cover the chopping, gouging, and chipping chores, it should have a four to six inch blade, be strongly made, and have a stout sheath (preferably of metal or synthetic) for safety. If you carry a straight knife in your pack, make sure that a fall won't drive the point through the sheath and into something important like your rain parka or your back.
No discussion of SAR knives is complete without talking about how to care for your knives. The most important maintenance activity is keeping it sharp. There are many ways to keep a knife sharp such as sharpening stones, sharpening steels, and ceramic rods. There are specialized powered sharpening devices as well. Most SAR knives are best maintained with a sharpening stone or one of the specialized sharpening rods. I use a diamond impregnated ceramic rod with a triangular cross section. This rod has one edge that is very rounded, another that had a slightly curved corner, and a sharp corner. The rounded corners are shaped to sharpen standard serrated edges and work great. The flat surfaces of the rod are used to sharpen the conventional edge of the knife. The most important requirement in sharpening your knife is to keep the angle of the abrasive sharpening surface with respect to the edge constant. This ensures that the edge is restored and not modified or rounded. A sharpening angle of 25 degrees is about right for a general use blade. A blade used for finer cutting may use a 20-degree angle and a chopping blade may use a 30-degree angle. The edge can be course ground to restore it after heavy cutting and a ceramic sharpener can be used to give it a final polish. Your knife should also be kept clean and lubricated.
Next time we will talk about the multi-tool and its SAR applications.