Trying to picture this channel. Is it high on either side? If so, and there's enough depth, hugging the windward shore will shelter your boat from the wind somewhat. Might mean you can head in a straight line. My last marina had high rocky jetties on either side of the channel. You could definitely feel the difference in the force of the wind at high tide and low tide (14 foot tidal exchange).
I've had similar problems motoring in waves with a 9.9 on my C-27. I will never try that again; way safer to sail. However, how were you getting waves in a 15-yard-wide channel with the wind perpendicular to the channel? Were they refracting around a corner or something? In my experience in a narrow channel, even with wind, the water is usually pretty flat.
Got a lat/lon of this channel?
1972 Catalina 27