Scientific Anglers Sonar Stillwater Seamless Density Sink 1 / Sink 3 Fly Line
The Scientific Anglers Sonar Stillwater Seamless Density Sink 1 / Sink 3 is designed to get beneath surface chop while maintaining a straight, direct connection to your flies. Its blended-density construction combines a slower sinking running line with a faster Sink 3 head, helping the entire line descend smoothly rather than hinging between different sections.
- Sink 1 / Sink 3 blended-density sinking line
- Seamless Density technology for a smooth transition between sink rates
- 45 ft head length
- Overweighted by two line sizes
- Designed for multiple flies and long leaders
- Textured hang markers at 10 ft and 20 ft
| Feature | Detail |
|---|---|
| Line Type | Sink 1 / Sink 3 blended-density |
| Length | 45 ft |
| Construction | Seamless Density technology |
| Hang Markers | At 10 ft and 20 ft |
| Weighted Design | Overweighted by two line sizes |
| Use Case | Multiple flies, long leaders |
FAQ
How does the blended-density construction improve line performance?
The blended-density construction combines a slower sinking running line with a faster Sink 3 head, allowing the entire line to descend smoothly without hinging between sections.
What is the length of the fly line?
The line has a 45 ft head length.
Are there any markers to help with line positioning?
Yes, textured hang markers are located at 10 ft and 20 ft along the line.


Warren Hughes –
This line performs well in choppy waters. The seamless transition between sink rates keeps the line straight and helps flies reach the target without bouncing. The textured markers make it easy to find the right section when setting up.
Sam Buckland –
I’ve used it with multiple flies and long leaders. The overweighted design helps keep the line stable, and the blend between Sink 1 and Sink 3 feels natural during casting.
Natalie Mackenzie –
The 10 ft and 20 ft markers are very helpful for adjusting line tension. I noticed less line hinging compared to standard sinking lines, which improves accuracy in stillwater conditions.