Engineering Stack Exchange
Engineering Stack Exchange

Questions tagged [marine-engineering]

33 questions
16
votes
1 answer

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 incompatibility, and would like an answer that…
Ray Butterworth
  • 789
  • 1
  • 6
  • 13
15
votes
5 answers

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
  • 153
  • 1
  • 6
14
votes
4 answers

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-making resistance is very speed dependent, I…
Mika Sundland
  • 596
  • 1
  • 4
  • 18
5
votes
3 answers

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 system will actually produce forward thrust. Please…
user18610
4
votes
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
  • 141
  • 3
4
votes
0 answers

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. This got me wondering: how does the ship secure the…
Airsick
  • 41
  • 1
3
votes
1 answer

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 stuck at one mechanical problem. I want to make…
Praval
  • 31
  • 1
3
votes
2 answers

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-metre gash which cause the flooding of 3 water…
FluidCode
  • 67
  • 7
3
votes
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
  • 131
  • 1
  • 5
3
votes
3 answers

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 in passenger cars similiar to marine diesels?…
Palayil
  • 31
  • 1
  • 2
2
votes
1 answer

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 moment due to the restoration forces (gravity,…
Lucen
  • 23
  • 2
2
votes
1 answer

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 horizontally, presumably to keep them out of the way of…
Loid Thanead
  • 123
  • 3
2
votes
2 answers

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
  • 123
  • 4
2
votes
0 answers

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, SSBN-656, launched in 1966, and in which he was…
David Tonhofer
  • 121
  • 2
1
vote
2 answers

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?
diredragon
  • 21
  • 1
  • 1
  • 3
1
2 3