Why don’t ships look like fish? We often hear about the advantages of human designs inspired by nature. Common wisdom believes that natural evolution had centuries to perfect vessel design. We should be wise to take advantage of that, right?
Well, ships are different. They do not look like fish, for two very good reasons.
Fish use a really impressive swimming technique. This is not a simple doggy paddle. Watch the details revealed by a researcher who simulated the hydrodynamics of a fish swimming.
Figure 2‑1: CFD of Fish Swimming
Did you see the flow patterns from that fish simulation? Incredibly complicated! The entire fix body articulated and bent for those motions. We cannot bend the entire hull of a ship; that motion is just too complicated to reproduce with a mechanical vessel. We can’t build with flexible cartilage and muscles. The mechanical world requires stiff steel, hydraulics, and bearings.
Ships do not look like fish, because boats are built different than fish.
Boats are more like swans. Boats “swim” on the water surface. Fish swim under the water. If you want a fair comparison, ask why boats don’t look like swans. And actually, they do look a little like swans. (Figure 3‑1)
Figure 3‑1: Swan Body Versus VLCC Hull
The swan in this picture has a gently rounded bow and stern. Compare that to a very large crude carrier (VLCC), which also has a gently rounded bow and stern. The only difference is that we stretched the middle to make it long. Some of the details look slightly different, but the main concept is still the same.
Boats are not fish, or swans. They are better! Evolution works because it results from generations of trial and error to optimize for a specific environment or niche. Ships have done the same thing. Humans designed ships for more generations than I can count. Each generation improved on the previous one and worked for greater optimization. Our ships evolved too, we just have a different niche from nature.