The boat was drifting to fast for your chosen line.in a case like that a DI 3-5 or even 7 is needed to fish over the front ang get control of your line,even a DI 7 fished with a big wind will only be fishing about 1-2' down.because of the speed of the retrieve.
And remember if the boat is drifting at 5mph you will have to retieve at least at 6mph to have good contact with your flies.
Backdrifting or trawling is an option to a casual angler, but is not allowed in competitions.It will also fish your flies very high in the water.
The waves were 2-3' high off the Seat, what made you pick a slow inter.It was not even going to get below the wave troughs. On Sat ,I fished a DI 3 but then changed to a DI 5 and started catching.
Jim