In theory no matter how much you heel gravity will not let the keel come out of the water in theory.
What is monohull. Monohulls are boats that have one hull. A monohull boat is the typical design that most people imagine when thinking of a boat. A vessel such as a sailboat with a single hull compare multihull.
The movement is very different in itself. A multihull substitutes its breadth or beam for the monohulls heavy keel. The Monohull or single-hull boat is the most popular boat design today.
Instead of a keel it has two canting ballasted T-foils to provide righting moment and the ability to self-right the boat in the event of a capsize. The monohull or single-hull boat is perhaps the most common boat design in use today. Catamarans on the other hand have two hulls.
The new AC75 will be a fully flying monohull. The single-hull boat is called a monohull while boats with two hulls are known as catamarans and three-hulled or tri-hulled boats are known as a trimaran. Monohulls have a keel underneath their hulls which is generally very heavy made of lead.
Multihulls can develop an unpleasant motion in a big sea Upwind most cruising multihulls wont point like a monohull with a deeper keel and when it gets lumpy and fresh the motion can become distinctly unpleasant. Even when powered up a cat or tri will rarely heel more than 5-10 degrees before its time to reef. Monohulls heel upwind and when the wind is on the beam while catamarans stay flat but pitch upwind.
A monohull has just the one hull and displaces its volume in water. For the uninitiated the boats draft refers to how deep the boats hull sits within the water. Downwind cats feel like a house gliding on the ocean at speed while monos roll from side to side.