Which statement about displacement hulls is true?

Which statement about displacement hulls is true?

• A. Displacement hulls do not displace water at rest.
• B. All boats are displacement hulls when at rest because the boat displaces water in order to float.
• C. Displacement hulls plane easily at high speed.
• D. Displacement hulls are the same as planing hulls.

Answer: (B)

Understanding buoyancy is the key. A boat floats because it displaces a volume of water equal in weight to the hull. That means, regardless of hull design, the hull must displace water to stay afloat, even when not moving. So the idea that all boats are displacement hulls when at rest captures this fundamental buoyancy principle: floating relies on displacing water to balance the boat’s weight. The other statements aren’t correct because a displacement hull does displace water even when stationary, displacement hulls don’t plane easily at high speed, and displacement hulls are not the same as planing hulls, which rise up and skim on the water at speed.

Understanding buoyancy is the key. A boat floats because it displaces a volume of water equal in weight to the hull. That means, regardless of hull design, the hull must displace water to stay afloat, even when not moving. So the idea that all boats are displacement hulls when at rest captures this fundamental buoyancy principle: floating relies on displacing water to balance the boat’s weight. The other statements aren’t correct because a displacement hull does displace water even when stationary, displacement hulls don’t plane easily at high speed, and displacement hulls are not the same as planing hulls, which rise up and skim on the water at speed.