I gather that you will scull (row) rather than paddle the boat.
Back in the latter 60s, I had a real single scull, a racing single. On the 6-7' wave issue, you must mean tug or barge waves on the Cumberland. I had some big waves from Chris Craft on the Charles, and I had no trouble with them. Seldom did water come over the decks, and it never came into the cockpit area. But I did know enough to put my boat at an angle to the wakes so that they would pass in a way that the boat wasn't sitting at right angles to a single, tall wave.
"Real" racing singles are about 27' long, with round hulls a bit over a foot wide. One sits on rather than in the hulls. Balance and support to keep one from falling over are provided by the sculls (oars) which act like active pontoons.
Your craft is more like a S&G canoe, though narrow at 26". If there were no boat wakes or other wavy complications, the only possible problem I could see is that, if you are rowing as hard as you can, the hull might try to rise up at the bow as if to "plane." My suggestions: move the seat forward a bit, and don't row as hard as you can. A real racing single, because of its cutting bow and rounded cross section, doesn't rise much under effort.
The other issue is how your hull will perform in response to forces from the side, from strong currents under you or propagated waves reaching you. You have flat surfaces under and alongside of your design. You have sharp chines. The issue with flat surfaces is that they are vulnerable to water forces, more so than convex or rounded surfaces. Rising wave forces from under you will tend to toss the boat. Forces impinging on the sides will tend to roll the boat and slap it sideways. This is in comparison to "canoes" that have more arched or rounded bottoms and softer chines.
The effect of sharp chines is (for me) hard to predict. Current belief in my circles (whitewater paddlers) is that sharp chines actually allow a boat to be "looser", to skate across the surface of green (fast moving) wave surfaces. But this depends partly on how deep the chines are sitting. I think your chines might be less vulnerable than more rounded chines on some of my ww boats. But I can't guarantee it. If you row across a whirlpool typed current, be prepared to use those sculls (oars) for support, lest the cross currents grab the boat and throw it in an unexpected way.
I only flipped my single scull once in several years of training and competition. The ends of a competition single are sealed, all the way to the centermost eight feet or so. But I was not able to re-enter, and had to swim it to shore on a sewage-filled Charles River.
It will be interesting to hear how your design behaves under the strong pulses of force provided by long sculls on outriggers. It's easier to imagine how it would behave if paddles like a canoe or a kayak. I look forward to your reports.
