Questions tagged [naval-engineering]
23 questions
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Why would you launch a large ship by dropping it sideways?
I'm referring to the process shown in this video:
https://youtu.be/Quyr5R1Rbfw?t=20
Or this image from Wikipedia:
In it, a large warship is launched into the water by essentially dropping it sideways down some ramps and off of a pier. The ship…
aroth
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15
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Purpose of spheres and fins on submarine propeller
On a recently launched Russian diesel-electric submarine, the rear propeller has two distinct features. You can see spheres at the base of every propeller blade:
Also, the trailing edge of the shaft has four adjoining fins in line with the axis of…
Rupert Reckless
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4
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1 answer
How to design a reinforced concrete ship keel?
I am building a small ship (or very large sailboat) that will have a concrete ballast at the base of the keel. I am looking to increase the weight of the concrete (lb/ft3), but I also want to maximize the impact resistance of the concrete to resist…
Escoce
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4
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Do ships powered by nuclear reactors use water for shielding?
On a different Stack, I encountered an answer that was making a comparison to nuclear powered naval ships. It was stated that the physical shielding being used was various kinds of metals. This seems... odd to me.
I assume that water is probably…
Ellesedil
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3
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3 answers
X-form and cross-form rudders in underwater control
What are the advantages of using X-form rudders in comparison to cross-form rudders?
Why do some submarines, torpedos and underwater autonomous vehicles use X-stern control?
X-stern:
Cross-form:
mwweb
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3
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1 answer
Do submarines really have cranks for closing leaks?
It's common in submarine movies that when suffering some kind of shock (like a near miss by a torpedo or falling deep into a trench), water will start bursting into the cabin and the crew will run around turning little wheels or cranks to stop the…
Rag
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Longtitudinal Centre of Gravity for Ship Cargo
I did a Civil Engineering course some years ago and this question from my textbook, I have found what seems impossible to get the correct answer of 46.2 m for. By putting this question up I am hoping that I will be able to come to a conclusion on…
Rob Wilkinson
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Why did the Soviet Alfa-class submarines have a titanium hull?
My limited knowledge in engineering tells me:
Titanium is expensive, stronger and heavier than aluminium, lighter and weaker than high yield steel.
The most significant advantage of titanium is the good strength to weight ratio.
In case of…
Martin
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2
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1 answer
Name of a keel between the bilge keel and the main keel
I'm working on a seaplane and find myself doubting about the specific nautical term for a keel placed between the bilge keel and the main keel. This might be a bit academic in nature since I have a working way of naming it, but I'd rather take the…
AEhere supports Monica
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Hydrofoil for skeg-hung rudder with forward centre-of-effort
I am trying to see how much I can reduce the torque on a rudder post by changing the foil shape. I think I need a rudder with a centre-of-effort further ahead than average but I don't know what rudder series to use.
Balancing the rudder (in a spade…
avs
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Maneuverability calculation of a catamaran ship with azimuth thruster?
In a competition about ship prototype performance, my team decided to make a small catamaran ship with azimuth thrusters. This competition was originally about speed contest but due to COVID-19 it was replaced with report, video, and presentation…
swayz zywas
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vote
2 answers
Wire bearings on actuators on military ships
While reading about the Korvette K130 Braunschweig class of corvettes for the German navy, I noticed that almost all of the weapon systems are held in what I'd call a wire bearing.
I'd like to know what its actual designation and its purpose…
Richard Neumann
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How can I calculate the buoyant force on an object without knowing in advance the amount of water displaced?
Suppose I know the mass and volume of an object, as well as its exact shape and density distribution as a function of space (x,y,z). Without submerging it to determine the amount of water displaced, how can I determine the buoyant force? Is there…
Paul
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Why are aircraft carriers so expensive to build?
The aircraft carrier USS Nimitz cost \$4.5bn. The cruise ship Allure of the Seas cost \$1.2bn. Why is the difference so huge?
user11311
1
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1 answer
Would a Flettner rotor make sense for an ocean cruising trawler?
A Flettner rotor can be used to provide propulsion for ship from the wind.
Would it make sense to fit a Flettner rotor to a full displacement expedition trawler in the 55-70 foot class like a Nordhavn or Bering? These vessels are deep draft ships…
Wallace Park
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