When two differently shaped objects displace the same volume of water, their surface areas can differ significantly. For example, two cuboids with the same volume, such as a 3x3x3 and a 1x1x27, illustrate this point as they have different surface areas. Water displacement is not directly related to surface area, as demonstrated by comparing a steel-wool pad and a steel sphere of equal volume. The discussion emphasizes that hull shapes in vessels can vary, affecting surface area calculations despite identical water displacement. Ultimately, surface area can be computed from water displacement, but it will not be the same for objects of different shapes.