Questions tagged [marine-engineering]
The marine-engineering tag has no usage guidance.
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Why do cruise ship owners not declare their ships’ displacement?
Trying to find the displacement for a cruise ship on the Internet is extremely difficult. Generally it’s not given or if it is then it’s confused with gross tonnage which is something entirely ...
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With respects to the North Channel (Irish Channel), has a causeway ever been proposed for a crossing?
Former UK Prime Minister, Boris Johnson raised the issue of a bridge between Scotland and Northern Ireland; his impromptu estimate of £15 billion was probably a little wide of the mark.
The issues are ...
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What is the name of this power connector used in the USS Yorktown?
I found this in the USS Yorktown aircraft carrier (it’s open for public tours)
I know it’s a 3 phase connector of some kind, but what type of plug connects to it? Is it a nationwide standard or ...
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Finding a gear supplier for a contra rotating boat propellor [closed]
I’m the new propulsion engineer in a solar boat team (something like this https://energyboatchallenge.com/en/home-english/, solar class). This year I have to design and build a contra rotating ...
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How do you generate a wave scatter plot showing the probability of occurrence of sea states?
I need to generate a wave scatter plot(Hs,Tp) showing the probability of occurrence of sea states using a wave climate record sampled every 3 hours a day for a whole year. Does anyone know how to do ...
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Benefits of twin-in/single-out propulsion
I've seen, in some marine engine project guides, arrangements where you have two medium-speed engines coupled to one propeller through a gearbox instead of one larger engine running that propeller. I'...
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Power requirements for a 50,000 TEU container ship
I understand that this may be incredibly vague, but based on current container ships, does anyone have an idea of how much power a 50,000 TEU (TwentyFoot Equivalent Unit) container ship might require?
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Can a design where syringes draw and push water to manipulate buoyancy be classified as a buoyancy engine?
Beginner question here:
So my partner and I are trying to design a buoyancy engine where a motor operates a ball screw that draws and pushes syringes in order to draw and push water in the syringes(...
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Why aren't there many ships with transom bows?
Transom basically is a flat aft, usually vertical. It reinforces the structure, adds deck area, and because that the flat part is above the waterline, no fluid dynamic is hurt.
The extra deck area is ...
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How to calculate the force required to tip a floating dock
If I have the following I'd like to determine how wide the base of a floating dock would need to be to prevent tipping under certain weather conditions (wind & waves)
I'd like to build a modular ...
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How much longer could Titanic have remained afloat if it had gotten rid of its anchor and chain right after hitting the iceberg?
I am wondering how much longer the RMS Titanic could have remained afloat if the crew had allowed the ship's anchor and anchor chain to fall to the bottom of the ocean immediately after the ship had ...
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Disposition of the generators on the shipwrecked Costa Concordia
Recently I have been reading about the shipwreck of the Costa Concordia, unfortunately what I read is not online, so I have no links, but it raised a lot of questions.
A rock hit by the ship tore a 50-...
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Computation of the moment of restoring forces for a floating vessel
Some slides associated to the book Handbook of Marine Craft Hydrodynamics and Motion Control (2021 edition) are provided by the author of the book here.
At page 12 of the slides for Chapter 4, the ...
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How do cracks form on a ship's hull?
The oil spill in Mauritius would be caused by cracks in the hull. How can this happen? Is it possible to be caused solely by rough weather?
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What is the best practice for ensuring the best possible connection between a battery cable and a battery terminal
I've seen a number of opinions on conductive gels to ensure the best conductivity between battery terminals and battery cables. I'm interested in knowing an expert's opinion on the matter. I'm ...
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Auxiliary engines on cargo vessels, what types are used for what purpose?
On large cargo ships (dry bulk carriers, or tankers) there are main and auxiliary engines. Auxiliary engines can be internal or external combustion (generators vs boilers) and generate electricity to ...
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What are the 'poles' off the side off this aircraft carrier's flight deck?
Looking at a model of the HMS Ark Royal I found myself intrigued by the prominent 'poles' lining the flight deck. Some investigation on Google reveals that they can apparently be lowered to lay ...
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How the design of ship help to survive in the water
I have seen bigg cargo, and other ships, and I like their structure very much., a question come sin my that why the ship structure is like this.
Can anyone explain what was reason for this. I am not ...
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What is it about the cabin electrical supply on cruise ships that makes surge protectors dangerous?
Surge protectors are banned on cruise ships, and so are confiscated during boarding. Extension cords and cube taps etc. are discouraged, but not banned.
I'm asking specifically about surge protector ...
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Is the metacentric height independent of heel angle?
when the sides of a pontoon are verticle, BM(distance between center of buoyancy and metacenter) is given by I/V
As well as for a small angle that expression is true. But when the heel angle ...
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Will this water jet propulsion system design produce any forward thrust?
I am interested in building a very basic water jet propulsion system for a toy boat. Before I build it, I would like to know from a conceptual standpoint if this design of a water jet propulsion ...
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Finding phase velocity for froude number scaling
So I am calculating phase velocity of a wave for Froude number scaling for model testing of a boat. I got data from Lloyd's Rules saying for the specific sea area I did $H_s=3.6\text{ m}$ and $T_z=6.8\...
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Sea waves: Having trouble visualizing the difference between group celerity and celerity
What I know, if I'm not mistaken, is that group celerity is the speed at which the energy is transferred and celerity is the speed of the waves themselves.
Since sea waves basically transfer energy ...
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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 ...
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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:
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Preheating Diesel before injection?
Significant amount of heat is lost from an engine by various means, so to recoup the energy, is it possible to increase efficiency via heating of diesel fuel prior to injection using waste engine heat ...
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Detergency and dispersancy
Abstract:The detergency property in oil comes from a chemical additive called detergent which has a property of preventing the deposition of carbon deposits and wash it away.
There is also this ...
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Boat Hull Drag in Shallow Water
I paddle several different types of small craft in the ocean and bays near my home. One phenomenon I've observed is beyond my understanding of drag on a narrow displacement hull. When paddling in ...
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How does a cable-laying ship retrieve a partly-laid cable?
I was reading an article in the press this week about a project to lay an undersea cable across the Tasman Sea. The ship had had to return to port for repairs and return to complete the job later.
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Hydrogen in submarines: "keep below 8%" rule of thumb?
In the book "Against the Tide: Rickover's Leadership Principles and the Rise of the Nuclear Navy", Rear Admiral Dave Oliver (Ret.) narrates some of his experiences in the USS George Washington Carver, ...
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How Big can Hydrofoils get?
Is there a limit to the size of ships that can have hydrofoils (would an aircraft carrier work)? Would there be cavitation if the load was high enough, and to what extent would using larger foils help,...
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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 ...
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What mechanism in the radar that enables the switch between transmission and reception?
I think there is a mechanism that switches off the transmitter in order to turn on the receiver in the antenna. Do you know the technical terms by which this is done?
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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 ...
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How to divert solids from a downward vertical pipe
I am an electronics engineer trying to build one small underwater mechanical device (about 12 cubic cm) as part of a personal automation project. I have figured out the electronics for this, but I am ...
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Below what Froude number can I neglect wave-making resistance on a vessel?
I want to do some very simplified drag calculations on a vessel. My hope was that calculating the skin-friction resistance would be enough to get a good estimate of the surge resistance.
Because wave-...
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