Why is the Tip of my Floating Fly Line Sinking?


We recently had a customer reach out to us with a fairly common question we receive here at the shop, “Why does the tip on my floating fly line sink in the water?”. It seems counterintuitive that a floating fly line would sink whatsoever, right? After speaking with our Scientific Anglers representative, Jamie Lyle, he gave us some phenomenal information that we wanted to share with the world. Here is the reason that floating fly lines sometimes sink according to Jamie:

“First, what makes them (the tip of your fly line) float is diameter, coating design, and the density of gas-filled micro-balloons in the coating. Welded loops also help as they have increased mass as opposed to lines without a welded loop.

Second, sometimes you just get a line out of production that doesn’t quite perform as expected primarily due to insufficient micro-balloon density. It would seem easy to address this by simply adding more to the coating mix, but there is a tradeoff with line durability if too many micro-balloons are incorporated so it is a careful balance. SA wants these back (defective lines) to understand and correct any production or design issues.

Third, it is common for tips to sink once a leader and hydraulics get involved. A line that floats perfectly in a swimming pool has too little mass, especially in the tip, to overcome river hydraulics if attached to a leader which gets pulled under. Nylon leader materials absorb water and will sink over time, and fluorocarbon simply sinks from the get-go. This means that floating lines commonly don’t float perfectly under fishing conditions. No line manufacturer has solved this and, given the factors noted above, it is a reach that they will. 

That the Andro floats better than the Trout has little to do with the slickness and durability difference between Frequency and Amplitude Smooth lines, but it has a lot to do with the increased diameter and shorter front taper of the Anadro. It’s simply more of a cork on the water.”

- Northern Rockies Scientific Anglers Sales Rep, Jamie Lyle


  • Dave

    Another observation, many have chewed off the PVC coating on the tip of their fly line at the loop. Likely from knots, water does ingress into the fly line at that point. I used to see this a lot guiding in Big Sky.

    Snip off a little and redo your loop. Then use a thick/short piece of mono to use as your leader carrier. This water ingress becomes noticeably more annoying the lighter line weights you go.

  • Vic R

    Interesting – thank you.

    What is the best way to protect the coating? Any of the line dressings perform better than others for floating?

  • Don Gable

    Interesting and informative article.

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