Final answer:
Boats are most protected at angles where wave diffraction is minimal inside the harbor, usually at angles closer to the original wave direction. To determine the exact angle of protection, wave diffraction principles need to be considered, although the area directly behind the opening experiences the least wave energy.
Step-by-step explanation:
When a breakwater with a 50.0-m-wide opening is approached by ocean waves that have a 20.0-m wavelength, diffraction occurs. The boats inside the harbor will be most protected against wave action at the angles where the wave diffracts the least. This typically happens at smaller angles closer to the original direction of the wave. However, the exact angle at which the boats are most protected can be calculated by applying the principles of wave diffraction, which involves understanding how waves bend around obstacles and spread out after passing through openings.
For the scenario provided, if waves approach the opening of the breakwater straight on, the angle of max protection would relate to where the wave energy is diffused minimally inside the harbor. Ideally, boats would want to be positioned at angles or areas within the harbor where wave energy and thus wave action is significantly reduced.
In practice, the specific angle of protection can be complex to determine without additional information, such as the shape and depth of the harbor, which can influence the wave patterns. Nonetheless, the general principle is that waves will diffract or bend at the opening, and the inside area directly behind the opening will experience the least direct wave energy, providing a safer zone for boats.