Line Joining Knots
Tying line to line is critical. And when it's called for (for example, when you have a killer rig on 15-pound test line and you want to attach it to the 20-pound test line on your reel without having to retie the whole rig) you need a really good knot. These knots are tested and reliable for joining two pieces of fishing line.
Blood Knot
A blood knot (Barrel knot) is most usefully employed for joining sections of monofilament nylon line while maintaining a high portion of the line's inherent strength. Other knots used for this purpose can cause a substantial loss of strength. In fly fishing, this serves to build a leader of gradually decreasing diameter with an easy cast fly line attached at the large diameter end and the fly or hook at the small diameter end. The principal drawback to the blood knot is the dexterity required to tie it.
In tying the blood knot, the two lines to be joined are overlapped for 6-8 cm with the short ends of the two lines in opposite directions. The short end of one line is then wrapped 4-6 times around the second line and the remaining portion of the first short end brought back and passed between the lines at the beginning of the wraps. The short end of the second line is then wrapped 4-6 times around the first line and the end of this line brought back and passed through what is now an oval space between the first wrap of each set.
The above method has been called by Stanle Barnes (Anglers' Knots in Gut & Nylon, 2nd ed., 1951) "outcoil", and is contrasted with the method that resembles the finished knot from the start, "incoil". The images here are incorrect to present the finished knot as having its free/"tag" ends go from the center of the knot to the extreme ends; they in fact will immediately coil around the standing parts towards the extreme ends. In fishing line, and in other material if not deliberately set snug and maybe re-set after some initial tensioning, the outcoil form will transform into the incoil form.
The lines are moistened and the wraps tightened by pulling on the long ends of the line. This causes the wraps to tighten and compress, creating 2 short sections of 'barrel', which look much like a 'hangman's knot', that slide together. The short ends of the line are then trimmed close to the wraps, or one of the ends may be left intact to be used for a second fly or lure, called a 'dropper.'
This knot requires five turns of line, with each tag end around the overlapped standing end of line. Make one series of turns and tuck the tag end between the two lines. Then repeat with the second line. You can even tie together lines of different diameter. It's good for tying 15-pound to 20-pound test line but not so great for tying
15-pound to 50-pound test line.
Double Uni-Knot
It's two knots tied back to back, then placed together to form a strong connection. Leave plenty of line at the end of the knot on each piece of line you're joining. The ends help pull the two knots into one. Clip ends short after the double knot is created.
Surgeon's Knot
The surgeon's knot is a simple modification to the reef knot. It adds an extra twist when tying the first throw, forming a Double overhand knot, thus adding friction which makes the knot more secure. This knot is named for the fact that it is commonly used by surgeons in situations where it is important to maintain tension on a suture. Surgeon's knots are used in fly fishing as well as in tying quilts.
This knot makes it easy to join two lines, but one line must be short, since you have to bring the one end through the formed overhand loop. As with other lines, use a lot of overlapping line so that you can pull on all four ends to make it properly tight. Work with both lines together as you tie this, and make sure both loops are the same size to assure a strong knot.
Albright Knot
One of the most reliable knots for tying together two lines of unequal diameter, the Albright works well when you have to tie the 15-pound test line on your rig to the 20-pound test you currently have on your reel spool or when tying monofilament backing to a fly line.
