Ship bulb: what role does the "growth" play in the bow of the vessel below the waterline

Shipbuilding is an exact science. Therefore, every detail of the ship's hull is important and fulfills the task assigned to it.

At the same time, one can often come across the question on the net: why was it necessary to make a certain “growth” in the bow of the ships below the waterline? What role does it play in the overall design.

This detail, which is present in the bow of some ships, is called the bulb or nasal bulb. The term came to us from French, where it literally translates as "onion".

However, this part of the ship's hull has nothing to do with vegetables. Bulb was created to increase the strength of the elements of the supporting structure, as it takes on part of the load, in the case of ships, reducing wave resistance during movement.

In addition, the aforementioned drag reduction also has an economic effect, since it reduces fuel consumption by about 12-15%. In addition, the speed of the ship also increases.

In this case, it must be added that the above-mentioned advantages of the ship's bulb give the greatest effect when using this design in ships with a hull length along the waterline of at least 15 meters and at maximum speed.

It should be noted that shipbuilding is only one of the brightest examples of the application of this engineering solution. Bulb is also used to strengthen beams, columns, bridge supports, etc.

Comments

[Doctor]

I read this study, I do not know how true.

http://khramushin.narod.ru/Paper/DVO-03-01.html

They offer the following optimal body shape:

[Coward]

The nose with straight hull contours is not good in heavy seas. The nose burrows into the wave. Therefore, camber is made in the bow of modern ships, which allows the ship to “climb” the wave and reduce the impact of water on the hull structure on the forecastle.

[mmaxx]

It all depends on many factors and considerations. They also make a traditional collapse, they also make a nose piercing the waves.

[mmaxx]

I will, but later. And without reading, I'll post my thoughts.
What kind of ship is not clear. Kind of like a container ship. Only for container ships and ferries is high speed important. But here we see a monstrous low-tech construction. Reducing the volume of holds and deck area for containers. It is unlikely that the shipowner will like this for the sake of 1-2 knots of travel. These ships have one feature: the cargo is relatively light, but voluminous. Vessels with littered sides have fundamentally worse stability than ordinary ships with straight sides.
For all other ships (tankers, bulk carriers, etc., etc.), a gain in speed will not give anything at all. They don't need her. Vessels travel at speeds where the main resistance is friction. And here the surface area is greater and the friction is also greater. There are generally 2/3 of the ships, or even more - a cylindrical insert. Sections can be driven in identical beds. Unification in detail is excellent. Very handy for building.
It seems that the authors of the project were inspired by French capital ships of the late XNUMXth century.

[mmaxx]

Well .... Man, of course, a solid candidate of science. But to cut so much nonsense, far-fetched - it must be able to. Apparently, it was necessary to gain the volume of the article. So I put everything in there. Compare the hull of the seaworthy cruiser "Aurora" and the small destroyer, which just broke through the wave ..... And so everything in a row. We also found out that the modern military! shipbuilders have forgotten how to make seaworthy hulls. They would go back to the XNUMXth century. Yes, look at the then armadillos.
Ehehe ... You can concoct an entire article based on the inaccuracies of this article. Based on such prerequisites, I even somehow don’t want to delve into what can be sensible in this article. For example, I learned that the galleys had a bulb ram. I would show you a picture, shtol? And a huge pile of all sorts of inconsistencies, lies and fairy tales hides the essence. And there is no longer any desire to disassemble this essence. For the author does not know elementary things, replacing it with some kind of nonsense.
Well, instead of reading the article, I expressed my opinion.

[Stas157]

. what role plays a "growth" in the bow of the vessel below the waterline

How what? Measure bulbs!