Let's run through some fundamental friction hitches that every arborist would know, or at least should know. These friction hitches will help your progression if you're starting out in the industry.
English Prusik
Other names: Standard / common prusik, prusik hitch
Use: DdRT only
Pros: Very safe, easy to use and recognise
Cons: Can be slow for access and maneuvering in the tree, have to add a micro pulley to progress capture (lots of sit-back), have to body thrust
Obviously, we can't start off with fundamental friction hitches without mentioning the English Prusik. The English Prusik is tied with a loop of cord joined with a Double Fisherman's. A general guideline for the length, is about from your hand to your elbow to get the right size loop for your body.
So the English Prusik is very much used as a double rope technique climbing hitch. The reason for that is, if you're trying to use this on single line, it won't work very well and isn't suited for use with the rope wrench.
Start with a double wrap of the prusik. That's usually what it takes to hold about 80 kg of body weight. Use a wider-topped carabiner, for example, a D-shaped, a pear-shaped, or a HMS carabiner because everything can fit into the one carabiner.
Ascending on the English Prusik is hard work but the pros of that are every time you ascend with the body thrust method, you end up capturing your progress each time.
It's a very basic knot: to go up, you pull down, body thrust your hips and then progress the knot. And to come down, you literally put your hand above the knot and pull down.
To help ascent, butt your feet up against the trunk, lift your hips inline with your shoulders and then slide the prusik knot up to capture the progress.
It's a lot of work doing this and it's slow but this is very much a fundamental knot of the industry. Now to come down as I said, just put your hands above the prusik and pull down slightly.
So the trouble with the prusik is if you're limb walking with this hitch, it means that when you're coming in from the limb you have to keep body thrusting (or that similar technique) but you can add a micro pulley to the system, for example, a swing cheek pulley. This pulley will help with progression on this hitch. Install the pulley onto the rope underneath the prusik and add it into that HMS or pear-shaped carabiner. This will allow you to pull on the tail of the rope when limb walking in from a branch, to progress the prusik knot. The only downside of using these micro pulleys is you have a large distance of sit back, but it's a helpful piece of kit if you're just on an English Prusik or a blake's hitch just to make your life a little bit easier for limb walking back into the tree.
Asymmetrical Prusik (Schwabisch Hitch) & Distel Hitch
Other names: The asymmetrical prusik is also known as a Schwabisch prusik
Use: DdRT or SRT
Pros: safe, natural progression to eye2eye prusiks with improved upwards advancement, easy to learn, fairly beginner-friendly
Cons: sticky and lots of friction
A natural progression from moving on from the English Prusik is to move on to eye-to-eye hitches and one of the most sensible options is a reliable knot that doesn't slip on sit back. So the first prusik that comes to mind is the asymmetrical prusik, which is also known as a Schwabisch.
The asymmetrical prusik is really similar to the Distel hitch because they're tied similarly and have similar properties.
An asymmetrical prusik is similar to the English Prusik but you have all the wraps on one side, adjust friction by adding or removing wraps. To turn the asymmetrical prusik into a Distel, all you do is take the bottom wrap slacken it off and pass it on the opposite side of the rope and around the other way and then it means that the legs exit in opposite directions. And if that looks familiar to you, the Distel is essentially a clove hitch with stacked wraps just on one side.
One of the ideal pulleys to use with this is obviously the hitch climber pulley, so this gets added underneath of your knot. And with the hitch climber pulley, you've obviously got three points of attachment. The benefit of using the Distel and the Schwabish system over the English prusik is you can haul yourself up and then get progress capture with multiple pulls on the climbing line exiting the pulley. You can take multiple pulls with your arms to be able to start accessing but it is said that three pulls is probably the limit (to minimise the drop). So take the pulls on the rope above your Distel hitch, hold on to the progress with one arm and then you can just feed it through with the other hand and just make sure the knot locks off. Repeat that process for accessing the tree and then make sure it locks off each time.
These are faster knots than the English prusik depending on how you tie them and they can definitely be more reliable than say the faster knots like a VT (Valdotain Tresse) but this is a great progression to getting into like the faster eye-to-eye style knots.
Knut
Similar to a Happy hitch
Pros: Quicker than Distel, adjustable but still reliable, reliable knot on SRT (on sitback), shorter knot than VT (for SRT)
Cons: Not as quick as the VT, because it’s short you have less distance between fully open and fully closed.
So the next knot we're going to mention is a knut (not to be confused with the Knute hitch). This is a really good progression on from the Distel and the Schwabisch and the reason for that is it's a fast knot but it's still reliable enough that when you sit back, so long as it's tied properly, it's not going to be too quick and too slippy like the VT. And this is a really good knot for SRT and moving on to the rope wrench as well.
Similar to the Schwabisch and the Distel, this works perfectly on the hitch climber pulley and my personal favourite is 11.7 mm rope with 10 mm Armor Pruss. It makes for a really good reliable knot but also a fast knot for maneuvering around the tree. The cool thing about the Knut is climbers can make it adjustable with how fast you can go. This is done with the half hitch at the bottom. Release it to it's lowest point, so there is a lot of rope distance for slack to release these coils. Or if you shuffle the half hitch up to the coils, it reduces the amount of leg that the coils can release. For me, I always used to find the half hitch would creep but that's a really cool little adjustment for the knut.
Tying this for SRT work is obviously the same as double rope tying but the great thing about this knot is, one, it's a very reliable knot and two, in comparison to something like the VT, it's a short knot which means that it's not going to come into contact with your rope wrench which sits not too far above the knot.
VT (Valdotain Tresse)
Other names: Incorrectly known as French Prusik (which is a Machard)
Pros: very quick, once a decent amount of rope weight is underneath it will generally self tend very well if the rope & hitch are clean.
Cons: too fast for beginners, can cause the rope to twist (hockle), can stretch out making it possibly harder to reach (be voided / contact the rope wrench), more likely to creep
The last and final introductory friction hitch, or fundamental friction hitch, is going to be the VT (Valdotain Tresse) which is really commonly used.
When the VT is loaded up, usually a wrap and braid will drop down which stretches the knot out quite a long distance and sometimes comes into contact with the bottom of the rope wrench.
This is a great knot on double rope. It's a fast knot, so if you're looking to do big swings and reliably open up the knot, the VT is great for that. So with SRT, it is also a good knot and many people will use it. For me, I wanted something more reliable like the Knut and the reason being is, on SRT, when you're ascending and then wanting to sit back it can slip easier than others and I like having a knot which will reliably grab when you sit back.
The VT when the hitch cord is brand new brand is great, but can creep a lot quicker after it's had a little bit of wear. The other thing with the VT, when you're talking about SRT, is it's a lot longer knot and it is kind-of exacerbated when tied with 8 mm hitch cord. As I clip on a rope wrench with the VT, especially when you load it up, the knot is long. And then as you climb the distance between the top of the knot and the rope wrench can get pretty close, especially when the wrench collapses and then this is fully extended. So they can get a bit bound up together.
Conclusion
So we've run through a few fundamental friction hitches, going from the English prusik to the Schwabisch and the Distel to the knut and the VT and giving you a bit of a look at them on double rope and then on single line. Hopefully, this was helpful.