What the arbor knot does and when to use it
The arbor knot is a small, reliable loop that attaches fishing line to a reel spool. You tie it at the very start of spooling, before any other line goes on. The knot holds tight under the weight of line and the pull of a fish, and it won't slip or unravel once you've set it.
Use the arbor knot whenever you're putting fresh line on a spinning reel, baitcaster, or fly reel. It's also useful for attaching rope to a post or anchor point on a boat. The knot works because it creates a loop around the spool that tightens as tension increases — the harder you pull, the more secure it becomes.
The arbor knot is not the same as a loop knot for connecting two lines or tying a lure. It's specifically designed to grip a cylindrical object like a reel spool, and it's one of the first things a fishing person learns because you need it every time you re-spool.
Key Takeaways
- The arbor knot creates a fixed loop that tightens under tension, making it ideal for securing line to a reel spool.
- You tie it before spooling any other line, and it should sit flush against the spool with no gaps or twists.
- The knot works on spinning reels, baitcasters, and fly reels, and also holds rope to posts or boat cleats.
- A properly tied arbor knot will not slip, even under the full weight of a loaded reel or a fighting fish.
How to tie the arbor knot step by step
Start with the end of your fishing line or rope in hand. Wrap the line around the spool one full turn, going around the cylinder so the line crosses itself. You now have a loop around the spool with the working end (the end you're holding) on top.
Take the working end and tie a simple overhand knot around the standing line — the part that's already wrapped around the spool. Pull it snug but not tight yet. You should see a small loop sitting on top of the larger loop around the spool.
Now tie a second overhand knot in the working end, about an inch or two away from the first knot. This second knot acts as a stopper and prevents the first knot from sliding off the end of the line. Tighten this stopper knot completely.
Hold the standing line and pull it steadily. The first overhand knot will slide down and cinch tight around the spool. Once it's snug, trim the short working end close to the stopper knot. The arbor knot is now set and ready for spooling.
Common mistakes that weaken the knot
The most frequent error is tying the first overhand knot too loosely or not pulling it tight enough when you cinch it down. If there's slack in that first knot, it won't grip the spool evenly, and the line can slip under load. Always pull the standing line with steady, firm pressure until the knot is completely snug against the spool.
Another mistake is forgetting the stopper knot or tying it too close to the first knot. The stopper knot must be separate and far enough away that it can't accidentally slide into the first knot. If the two knots merge, the whole thing can unravel.
Some people wrap the line around the spool more than once before tying the overhand knot, thinking it will hold better. It won't — one wrap is enough, and extra wraps just waste line and create bulk. The knot's strength comes from the cinching action, not from multiple passes.
Finally, don't trim the working end too short. Leave at least a quarter-inch of line beyond the stopper knot so you have something to grip if you ever need to untie it. Cutting it flush makes the knot harder to undo and can cause the stopper knot to slip.
Arbor knot on different types of reels
On a spinning reel, the arbor knot sits on the spool shaft and should be positioned so the line comes off cleanly when you cast. Make sure the knot is centered on the spool and not twisted to one side. The line should lay flat against the spool as you begin spooling, with no gaps between wraps.
A baitcaster spool is smaller and more precise, so the arbor knot needs to be tied even more carefully. The knot should sit exactly on the spool shaft with no wobble. If it's off-center, the line will wind unevenly and can cause backlashes or uneven tension across the spool.
On a fly reel, the arbor knot is tied the same way, but the spool is often larger and the line thinner. Take extra care that the knot is tight and centered. Fly line is expensive, so you want that first knot to be absolutely secure before you start spooling.
For boat rope or dock lines, the arbor knot works just as well around a cleat or post as it does around a reel spool. The principle is identical — the loop tightens under tension. Just make sure the standing line is the part you're holding steady, not the working end.
Testing your arbor knot before you spool
Before you load the reel with line, give the arbor knot a hard pull to make sure it holds. Grab the standing line and pull with real force — the knot should not slip at all. If it moves or loosens, untie it and start over. It's much easier to fix now than after you've spooled fifty yards of line.
Look at the knot from the side to confirm it's sitting flush against the spool with no twists or gaps. A twisted knot can catch line as you spool and create weak spots. If you see any irregularity, redo it. A few extra minutes now prevents frustration and lost fish later.
Once you're satisfied the knot is solid, you can begin spooling. Keep light tension on the line as it goes on so the wraps are even and the arbor knot stays in place. The knot should not move or rotate as you spool — if it does, stop and check that the stopper knot is holding.
When to replace the arbor knot
You'll retie the arbor knot every time you re-spool your reel, which might be once a season or several times a year depending on how much you fish and whether you change line types. If you switch from monofilament to braided line, for example, you'll want fresh line on the spool, which means a new arbor knot.
If you notice the line slipping on the spool during a fight or while casting, the arbor knot may have loosened. This is rare if the knot was tied correctly, but it can happen if the reel takes a hard impact or if the knot was never fully cinched. In that case, you'll need to re-spool and tie a fresh arbor knot.
Some anglers retie the arbor knot at the start of each season as part of their regular maintenance, even if the line looks fine. This ensures the knot is fresh and secure and gives you a chance to inspect the spool for damage or corrosion.
Frequently Asked Questions
Can I use the arbor knot on a conventional reel?
Yes. The arbor knot works on any reel with a cylindrical spool, including conventional reels, baitcasters, and round reels used in saltwater fishing. The principle is the same — the loop tightens around the spool shaft under tension.
What if the arbor knot keeps slipping?
The knot is probably not cinched tight enough, or the stopper knot is too close to the first knot. Untie it completely and start over, pulling the standing line with steady, firm pressure until the first overhand knot is completely snug against the spool. Make sure the stopper knot is at least an inch away.
Do I need to use the arbor knot if I'm using a backing line?
Yes. The arbor knot still goes on the spool first, and then you tie the backing line to the arbor knot using a different knot, such as an improved clinch knot or an Albright knot. The arbor knot is always the foundation.
Can I tie the arbor knot with braided line?
Yes, though braided line is slipperier than monofilament and requires a slightly firmer pull when you cinch the knot. Make sure the stopper knot is especially secure and pull the standing line with extra pressure to ensure the first knot grips the spool completely.
How much line should I leave on the spool after tying the arbor knot?
Leave at least a quarter-inch of working end beyond the stopper knot so you have something to grip if you need to untie it later. Trim it close, but not flush — a tiny bit of tail makes the knot easier to undo without damaging the line or spool.