The Scientific Anglers SONAR Saltwater Intermediate Fly Line is the line that closes the gap between a floating line and a full sinking line — and in saltwater fly fishing, that gap is where some of the most productive fishing happens. The clear slow-sinking head cuts through the surface film and gets your fly just below the chop, eliminating the drag and surface disturbance that spooks fish on calm flats while keeping the fly in the strike zone longer than a floating line can. At 1.25 inches per second, it sinks slowly enough to fish shallow flats without hanging up, but fast enough to stay below the surface and out of the wind. From bonefish and permit on the flats to redfish in the marsh and tarpon in the backcountry, the SONAR Intermediate gives you a presentation advantage that fish can't see and can't refuse.
When to Fish an Intermediate Line in Saltwater
Most saltwater fly anglers default to a floating line — and for good reason. But there are conditions where an intermediate is the better tool. When wind chop is breaking up the surface and creating drag on a floating line, an intermediate cuts through and maintains a cleaner connection to the fly. When fish are cruising just below the surface and a floating line's shadow or surface disturbance is putting them down, a clear intermediate head is effectively invisible. When you're fishing a crab or shrimp pattern that needs to sink naturally rather than being pulled across the surface, an intermediate lets the fly behave the way the real thing does.
The SONAR Saltwater Intermediate is engineered specifically for tropical saltwater conditions. Tropi-Core technology keeps the core supple and the coating from stiffening in the heat — a critical feature for lines that spend their lives in the sun on a flats skiff. The clear head provides maximum stealth in the gin-clear water where bonefish, permit, and tailing redfish live.
Scientific Anglers SONAR Saltwater Intermediate – Features
- Clear slow-sinking head — near-invisible in clear saltwater, eliminates surface disturbance and line shadow
- 1.25 ips sink rate (Intermediate) — gets flies just below the surface without hanging up on shallow flats
- Tropi-Core technology — keeps the core supple and coating flexible in tropical heat and direct sun
- Engineered for saltwater — salt-resistant coating and construction built for repeated saltwater use
- Weight-forward taper — loads quickly for fast presentations to moving fish
- Available in WF-7-I through WF-12-I — covers the full range of saltwater fly fishing applications
Line Weight Guide for Saltwater Fly Fishing
- WF-7-I — bonefish in light wind, smaller permit, snook in calm conditions
- WF-8-I — all-around bonefish and redfish line, moderate wind conditions
- WF-9-I — redfish, larger bonefish, permit, windy flats conditions
- WF-10-I — permit, large redfish, juvenile tarpon, heavy wind
- WF-11-I — tarpon, large permit, heavy flies in strong wind
- WF-12-I — large tarpon, big flies, the most demanding saltwater conditions
Scientific Anglers SONAR Saltwater Intermediate Specs
- Sink Rate: 1.25 ips (Intermediate)
- Head: Clear sinking
- Taper: Weight-forward (WF)
- Line Weights: WF-7-I, WF-8-I, WF-9-I, WF-10-I, WF-11-I, WF-12-I
- Technology: Tropi-Core
- SA ID: SA SONAR SWTI WF X I (X = line weight)
- Best for: Bonefish, redfish, permit, tarpon, snook, saltwater flats fishing, tropical fly fishing, backcountry fishing