We run on Mercury Outboards!
The Scientific Anglers Frequency Full Sink Fly Line is the best choice for stillwater fly fishing in deeper water where you need to get your fly down to the fish. This Type 6 full sinking fly line sinks at 5-6" per second. Its thin diameter cuts through the wind enhancing the castability of it in the wind. This is a great price on a great fly line.
A tip for fishing sinking fly lines is to use a 3' to 5' section of tippet for a leader. The shorter length will keep the fly down deeper and the short length turns over easily so you don't need a tapered leader.