The force that is at work is gravity. If you are thinking of bouyancy, it is not a force.
The heavier the boat is loaded, the deeper in the water the boat will float.
by making a boat and that way a boat can float anytime in water
anything you want that can float. You can be creative.
Without gravity, a boat wouldn't be able to float on water, so yes, gravity allows a boat to float (as well as sink into) water. A boat floats from buoyancy force. The buoyancy force is from the volume of water it displaces with it's shape below the water. The buoyancy force is equal to the volume of water it displaces multiplied by 62.4 lbs. per cubic foot (the density of water). So if the boat displaces 20 cubic feet of water with it's hull or shape it can hold 20 x 62.4 = 1248 lbs. of self weight plus cargo. Obviously there should be a factor of safety on that. In summary, a boat needs two things to float on water: Gravity and buoyancy force. Gravity keeps the boat on the water in the first place, but the buoyancy force is the actual thing that keeps the boat afloat. Technically, it is the buoyancy force that allows a boat to float, but if you want to get really technical, it is gravity in the first place that allows a boat to float on water.
Put it on a boat?
The key to make a boat float is that the boat should weigh less (or have less mass) than the water it displaces.
I can make a iron nail float. Simply melt some lead and the iron will float on top of the lead. Your question seems to be with regard to how do Boats float and the answer is Bouyancy. The Boat displaces a volume of water and if the weight of the displaced water is less than the weight of the boat, the boat will float.
round
fowlled it into a sail boat.
make it into shape of a boat
no design matters. it is the force of water resistance and upthrust that are level that allows any boat to float