Marine Definition and 63 Threads

This privately held company developed a technology to extract H from methanol stored onboard marine craft, then the H can be used in a fuel cell for power. I assume the reason for a H fuel cell vs a direct methanol fuel cell (DMFC) in a marine vessel is that direct methanol cannot deliver large...

For my internship I have to test and certify a Marine diesel engine. We are trying to run a few tests in our workshop, but this obviously means we can't use the sea or a river as cooling. We bought an IBC tank, which can hold a 1000 liters of water. The water from the tank will be running...

My dad has been asking about some speakers for his boat, something that will move a bit of air, not too big though. I'm thinking 1x12. He also wants it bluetooth and powered externally, so it doesn't drain the boat battery. So I'm thinking 1x12 speaker in a small box that can fit inside the...

I've seen these devices on shores as well as on ships , like a horizontal tube rotating slowly around it;'s axis. Now from what I know it's a type of radar, and unlike phased array it rotates it's beam physically by means of using a motor to rotate the antenna itself , what I want to know is...

I have a "first cousin, twice removed" who died in the Pacific theater of World War 2. He died on September 18, 1942. He was buried in Honolulu, Hawaii. He lived in Chicago, IL when he entered the service, so apparently the US Military did not bring bodies of killed soldiers back home in WW2. He...

Right, I'm ambitious about joining the Indian Navy via Graduate entry scheme or at least some private companies like Maersk. But recently a relative who took Diploma in Marine Engineering said that the industry is flooded and it's currently unemployable. He said 4th Engineers are being fired...

I attempt the solution on the attachment. The answer is 0.344 litre. Do I change 7L to m, so it is 0.007 cubic meters

I recently came back from a cruise on MS Eurodam. The ship was equipped with two 17.6 MW Azipod propulsion systems. The captain explained a bit about them in a Q&A session, and I researched a bit more because I'm curious as an engineer. I'm sharing it here on PF for the benefit of other...

Hello, I am looking to change my major to become a marine biologist. As I view the different programs that are out there I have come into a couple of conflicts I was hoping you guys could help me with. The first being I have the option to either major in biology and get a masters in marine...

I"m a big fan of the KISS principle in engineering. I'm also a boater. I just found something I wanted to share. It is a permanent magnet motor in which the propeller itself is the rotor. The video hints that it works with simple reversals of polarity similar to a stepper motor. That...

Hi, In some marine isolated electrical systems I saw that only one phase insulation resistace is monitored. Why? If something happens on other phases I will have no information about that or...? Regards!

Hey there! I'm an IT guy and found this forum through searching on replacing UPS batteries with deep cycle 12v marine batteries. The reason I was looking is I happen to have 4 spare Compaq rack mount UPSs with dead batteries taking up space in my basement. I was thinking of putting in a backup...

What is the current habitat range of Turritopsis dohrnii or the "immortal" jellyfish? I know that there are multiple species of the Turritopsis genus and that the species dohrnii have recently increased its range by ballast water spread. What is the current range of the exact species dohrnii?

The battery post is moving up and down. It doesn't seem to want to come all the way out. Will the battery still perform properly or is it damaged? Can it be repaired? Pictures attached.Thanks in advance.

Hello folks! I hope all of you are having a good day. Here is my question: How can I calculate the thrust needed by a marine propeller to move a body of about 120 kg? Also, as long we are talking about marine propeller, our propulsion is in water and not in air, so what about the rpm? Are they...

Hi, I've had a longstanding interest in working at sea. The prospect of working as an engineer at sea is quite an exciting one. I have a degree in mechanical engineering and 2 years (non relevant) experience in design and manufacture in the oil and gas industry. Im just wondering if it's...

I'm in search for a career that is 'earth' related. I also have interests in the ocean. So, my choices come down to; Earth Sciences & Marine Biology / Oceanography. Was looking for a career in the space industry, or renewable energy, but found most of it to be engineering based. And I don't...

I have a some problem about marine propulsion. Assume the 4 engine-fast gunboat is moved by forward two engines. The boat get 10 knots. Then if other Aft two engines operate gradually. You know the boat doesn't get 20 knots speed. What are the reason for that? Explain theoretically? Thanks for...

http://www.bbc.co.uk/news/uk-england-cambridgeshire-34593948 Thank you for your service. RIP. A US Marine Corps pilot has died in an F-18 jet crash, close to an RAF base. The jet came down on farmland in Redmere, near Ely, Cambridgeshire, with the alarm raised at 10:30 BST. The Hornet...

Just came back from diving in Cuba. These are some sort of jellyfish or other invertebrate but I haven't found any reference to it. They have no tentacles, just a round body like a kiwi fruit. Extremely transparent and incredibly fragile. Video...

Hello, I'm looking to try to use a gyroscope to determine the rocking motion (just side to side - not back and forth) of a boat while it is traveling forward or sitting still in the water. Specifically, I'm looking for the boat's angle from vertical and this angle's velocity. Can I do this...

New to the forum, and can't find this info or examples on the web. I'm interested in the possibility of coupling multiple DC brushless motors to a single drive shaft for main propulsion on a 45-50', twin screw boat. Lots of sail boat examples are given, but my interest is in a power...

So I am trying to find the depth of immersion of this particular boat model, which has curvilinear edges (subparabolic edges) on each side. The figure of the pontoon is shown below So now when I place this pontoon in water, the height of the water that rises, called the depth of immersion is...

Hi I want to study marine biology. I just want to know how long does it take to study this field

Yes, I know "This is the Physics Forum KimG" BUT, this is science related so I figure it counts. I'm sitting here right now at 10:27 p.m. STILL trying to figure out my Physics homework (Which by the way if half of the reason I joined this Forum in the first place) and thinking to...

A tidal barrage contains an area of of sea of 200km2 and the tidal range 6m at spring tides and 2m at neap tides. What would be the average power output over the year? Any help would be great,

What's the difference between oceanography and marine geology?

I don't venture onto this bit of PF, very often but I thought that someone might have some information on this subject. Out of date distress flares are an embarrassment to sailors. Local waste disposal services don't handle them and even most Coastguards won't touch them. It is sometimes...

Despite the name interceptor, this is marine as in water, not marine as in marine corps. Interceptor plate on a boat is like a horizontal flap (airbrake, alieron, elevator) on an aircraft but is mounted below the water. Usually it's a flat rectangle (not airfoil) that drops down from the bottom...

I was wondering if anyone knew of the potential downsides of using this material to replace a piece of 1/4 low carbon steel that is decaying and is a backing plate inside a hull of a 28 foot sailboat. I would be replacing it with 1/2" G10/FR4 fiberglass board minimum and could go to 3/4 inch if...

Dear sir/ma'am, I am a bachelor of Survey Science and Geomatic student from Malaysia. This is my final year and I have to complete a research, where my research is about to evaluate marine gravity and satellite altimetry data on coastal region. 1. Homework Statement I am in the middle...

On finding pitting on a water tube marine boiler, after inspection, how do i check for its safe operating pressure? Would it be safe to fire it and bring it up to its design pressure as stated by the maker?

Folks, Can anyone recommend any books regarding the argument of we unlikely came from 'adam and eve' (devine intervention) versus evolutionary evidence etc etc Thanks bugatti

What possible type of engineering could I major in that would also allow me to work with marine animals?

Hello! I have found a lot of useful information on this sight since I've been lurking, but I have decided to merge from the shadows to ask a few questions. I have been an active duty Marine Corps Infantryman (MOS 0351 Assaultman) for the past four years. Now, finally at the end of my enlistment...

Hi i am trying to find rated power output for turbine for tidal, and energy capture per cycle i am putting limits to integration T1 and T2 i know i can assume period of 12 hours and 25 mints which is 745 mint for quarter cycle T1 would be 745/4 so T1 is 186.25 but i don't know how cani find...

Click on the right side of the picture to scroll through. http://www.telegraph.co.uk/earth/earthpicturegalleries/7875310/Scientists-discover-new-marine-species-in-the-hidden-depths-of-the-Atlantic-Ocean.html

Need help with understanding with visual diagram how sonic antifouling for marine vessels work.

If this doesn't make your blood boil, you've got something wrong with you. http://www.facebook.com/group.php?gid=355406162379&ref=mf" The money will go to help pay for this cost, and for other families of fallen heroes. Bill O'Reilly promised to pay all of the costs is Mr. Snyder does...

Which is a better choice for a career? Which is more interesting? Which has more scope, both in terms of employement and development as an industry? If none of these, then what about robotech engineering (can I work for a space agency if I go into this field?) or geochemical research...

I wonder how marine life can withstand the enormous pressures at the bottom of the ocean without being crushed. The deepest part of the ocean, the Mariana's trench in the pacific, which is about roughly 30,000 feet deep, does have some rather strange-looking sea life inhabiting it. How do these...

just wonder if there any charts are available on marine species by depth and pref. location, esp. in depths with pressure between 60 and 150 PSI, or approx. over 100 feet

I have wanted to review these ecosystems with other biologists for a while now, usually we just stay on aquarium web sites and just now I found yours. enjoyed reading through the threads and seeing the depth of the discussion, really great place. there is about 10 years dedication into...

Hi... I actually graduated two years ago so maybe it's a little late to be posting this. I've been doing community work since leaving Uni but I miss science. I have a Masters in Marine Science and Management and a BSc in Environmental Biology. My dissertation was on genetics and I have some...

Anyone here into sailing or boating? I haven't left my mooring yet, been testing it at anchor but my new Humminbird 383 insists I'm pointing NE when I'm actually pointing SW. It changes its mind every so often, occasionally it's correct, but seems to return to this position. I've left it...

Is there a noticable diffence in torque required to spin a marine propeller at a constant rpm (say 2000rpm) when under a different water column? (5m vs 35m)

Wreck of renowned British warship found in Channel http://news.yahoo.com/s/ap/20090201/ap_on_bi_ge/shipwreck_discovery Odyssey has an ongoing legal matter with Spain over another wreck that was salvaged, the Spanish galleon Nuestra Senora de las Mercedes y las Animas, which sank off Portugal...

Hi, I'm new to the forums and I'd like to bounce an idea off of someone :biggrin: Although I've got a physics degree, I have successfully managed to forget a lot of it as people tend to do when not practicing, and I was wondering if someone would kindly pick some holes in an idea I've had...

Hi all, In a document, I read the two terms above and it really puzzles me. Please help me to see the difference between the two. Thanks

I was doing some reading on the effects of air blasts from asteroid impacts when I realized that I've never seen any data of the potential effect on marine life. Since sound travels farther and faster in a liquid, wouldn't an asteroid impact in a large ocean (liquid) have a more profound...