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Questions tagged [ships]

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Astute-class submarine nose module shape

The nose module features a continuous ridge running along it's side. The rest of the hull has the typical "cigar" shape as other sub designs. (Q1) Does the "ridge" have a proper ...
Ionkz's user avatar
  • 21
1 vote
1 answer
112 views

Keel Attachment

In Technik Museum Speyer I have seen strange attachments to the keel of Rescue Ship John T. Essberger. What is their purpose? Are they anyhow related to hydrodynamics? They are quite small compared to ...
banterCZ's user avatar
  • 113
1 vote
1 answer
94 views

Why do high speed boats have 2 speed transmission?

For example in this link you can see a 2 speed gearbox for a high speed boat http://www.coanracing.com/custom-block2/transmissions.html/xtreme-marine-transmission.html , what even is the purpose of ...
Timothy Scherer's user avatar
0 votes
0 answers
67 views

Wooden Sailing Ships - Why The Drag Pieces of Common Logs Were Shaped like Sections of a Circle?

I was reading the website What is the difference between a nautical mile and a knot?, and it said The common log was a rope with knots at regular intervals, attached to a piece of wood shaped like a ...
MeltedStatementRecognizing's user avatar
0 votes
1 answer
57 views

Which type of aircraft carrier is more cost-effective and more reliable in the long run? [closed]

All of the >100,000 tonnes US aircraft carriers are nuclear-powered. On the other hand, all Chinese and British aircraft carriers are conventional powered. Which type of aircraft carrier is more ...
user366312's user avatar
1 vote
4 answers
1k views

Ship Stability And Overturning Moment

Here a ship that is tilted due an external force . the buoyancy and weight force will create an overturning couple that will rotate the ship in the clockwise direction. Now, the moment equation was ...
Jesse Flynn's user avatar
0 votes
2 answers
578 views

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? ...
user avatar
0 votes
4 answers
196 views

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 ...
CrystallizedRefresher's user avatar
0 votes
0 answers
82 views

Does somebody know what this piece of equipment is?

I got this equipment from a sailor, I have no idea what this is. Does anyone know?
Neill's user avatar
  • 1
0 votes
2 answers
599 views

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 ...
user57467's user avatar
  • 281
0 votes
1 answer
172 views

Ship Longtitudinal Centre of Gravity Position

This question is designed to get help from someone (with some important important questions), so that I can get an understanding on why I cannot quite get the correct answer for this question ...
Rob Wilkinson's user avatar
2 votes
2 answers
309 views

How are ships stacked ontop of other ships?

As shown at this skeptics SE post, there are ships that carry other ships as cargo, etc... My question: how are the ships stacked onto the flat bed ship? Is there some kind of specialized crane that ...
Daddy Kropotkin's user avatar
3 votes
2 answers
697 views

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-...
FluidCode's user avatar
2 votes
1 answer
207 views

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 ...
Lucen's user avatar
  • 23
2 votes
0 answers
69 views

How to move a stuck 400m cargo ship? [closed]

I am definitely not the captain of the Evergreen what is currently stuck in the Suez Canal: https://www.google.com/search?q=Evergreen+Suez+Canal But from an engineering point of view, what would be ...
SutoTi's user avatar
  • 21
3 votes
4 answers
2k views

Why one big cargo ship is more efficient than 10 or 100 smaller ships?

Given the fact that small container ships are easier to manufacture than big container ships.. then why is it considered better to build bigger ships instead of many smaller ships? And to see why ...
AIon's user avatar
  • 157
1 vote
0 answers
89 views

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 ...
swayz zywas's user avatar
2 votes
2 answers
681 views

Why are Chinese aircraft carriers conventionally powered? [closed]

China has nuclear-powered submarines, which means China is able to manufacture portable nuclear power-plants. Then, why is the latest Chinese aircraft carrier Shandong conventionally powered?
user366312's user avatar
10 votes
5 answers
1k views

Can a riverboat tack upriver?

Note: This question originally appeared on the Physics site (see here) and was closed for being off-topic. Whoops! If ships at sea can tack in a zigzaggy pattern by converting backwards force from the ...
Palbitt's user avatar
  • 239
2 votes
2 answers
301 views

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 ...
Rob Wilkinson's user avatar
1 vote
1 answer
2k views

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 ...
Superman.Lopez's user avatar
2 votes
1 answer
3k views

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 ...
Loid Thanead's user avatar
-1 votes
1 answer
84 views

Describe the replacement flow of water at the stern of a large ship

What is the flow path of water immediately at the stern of a large, deep draft ship (like a container ship 250+m long for example)? Does it fill in the area displaced by the hull from all sides ...
Mark's user avatar
  • 1
1 vote
0 answers
312 views

How to find Ship Transverse Metacentic Height

I did a Civil Engineering course some years ago and from my textbook I had this question. I found that a very interesting question, but unfortunately I haven't been able to find a solution to this. I ...
Rob Wilkinson's user avatar
1 vote
2 answers
896 views

Why not build container ships from plastic?

This may sound crazy but bear with me. I was thinking about why cargo ships are built from such heavy material as steel, while smaller boats are often made of plastics. I know cargo ships carry a lot ...
kramer65's user avatar
  • 113
2 votes
0 answers
103 views

Regarding the ITTC Guidelines for Ship CFD applications

I was reading through the ITTC – Recommended Procedures and Guidelines - Practical Guidelines for Ship CFD Applications (https://ittc.info/media/4196/75-03-02-03.pdf) document and this little thing ...
ASPVL's user avatar
  • 21
1 vote
1 answer
2k views

Why don't modern warships still use cannons?

This question is about a technical aspect of naval warfare, and I think that this site is the closest fit. History would have been my next guess. In the TV show “The Last Ship” the protagonists have ...
Martin Ueding's user avatar
1 vote
3 answers
679 views

Why are aircraft carriers so expensive to build? [closed]

The aircraft carrier USS Nimitz cost \$4.5bn. The cruise ship Allure of the Seas cost \$1.2bn. Why is the difference so huge?
user avatar
2 votes
2 answers
2k views

Thrust generated by a ship

While reading about airplane engines on the internet, it is common to find figures of their thrust, in kilo Newton. However, in the case of ships and naval vessels, when talking about the engine, the ...
Harsha's user avatar
  • 123
4 votes
0 answers
126 views

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. ...
Airsick's user avatar
  • 41
9 votes
1 answer
880 views

What kind of ship is this?

I've recently been on Rügen and I have seen this: Does anybody have an idea what this is? (To give Google a chance: A ship with four "towers" made out of steel on it. They looks a bit like high-...
Martin Thoma's user avatar
4 votes
1 answer
820 views

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 ...
Escoce's user avatar
  • 141
24 votes
2 answers
6k views

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 ...
aroth's user avatar
  • 343