# how high should oil prices get for sea shipping to switch to coal? can this realistically happen? **URL:** \ **Category:** Factual Questions\ **Created:** [December 19, 2009, 10:48pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894 "2009-12-19T22:48:41Z")\ **Posts on this page:** 16\ **Page:** 2
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [December 21, 2009, 2:45am UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/21 "2009-12-21T02:45:16Z")
> [@OtakuLoki](#): > > Ignoring any problems with pollution controls, I think that the biggest thing to look at is the difference between the maintenance and manning costs of a steam plant vs. a diesel plant. > > **Snipe 70E** has already pointed out that there are many diesel plants that are operated without anyone in the engineroom - the computer monitors the operation of the diesel, and flags any unusual conditions for the bridge watch to have investigated. I suspect this means that a ship running on a diesel plant can get away with having one, or maybe two, trained diesel mechanics, to handle any minor problems might come up during a voyage. (Major problems are going to be beyond the means of shipboard repair, anyways.) Which makes for a fairly cheap payroll associated with propulsion. Maintenance costs for a diesel plant are similarly relatively cheap: there is some wear and tear on the moving parts, but having a good lube oil system going keeps the moving parts lubricated, cleaned, and cooled. Some of the contaminants in the fuel can be pretty active, but again AIUI most fuel oil these days is refined to minimize the sulfur content, which was the big corrosive contaminant I’d heard about back in the day. > > With a steam plant your manning goes up considerably. For a quick comparison of how a steam plant can multiply manning considerations, consider two old USN cruiser classes: [USS _Ticonderoga_ class](http://en.wikipedia.org/wiki/Ticonderoga_class_cruiser), which uses gas turbine power plants vs. [USS _Virginia_ class](http://en.wikipedia.org/wiki/Virginia_class_cruiser), which used nuclear fired steam plants. I can’t claim that they are exact duplicates except for their power plants, but they’re a pretty good match in size, mission, and armament. The _Tico_s had a crew (per Wikipedia) of under 400 men; the _Virginia_s had a crew of just under 600 men. That’s a 50% increase. I’m not going to claim that _all_ of those extra warm bodies were in the engineering department, but I believe that most of them were either there, or added to other departments to support the extra crew loading that the expanded engineering department required. And that’s comparing to gas turbine plants, which are more complex and require closer monitoring than a civilian diesel does. > > Aboard _Virginia_ we had a watch team any time the steam plant was in operation (and this is ignoring anyone whose duty was solely for reactor-only operations) that numbered about a dozen. Now you can’t make a complete comparison between civilian manning and naval manning: Naval plants run with more bodies because that’s the best way to deal with unforeseen situations. So, cut that in half for a civilian plant, and we’re still talking about having five or six people on duty at all times in your steam plant. To cover three shifts, that means you’ve replaced that single or two diesel mechanics with eighteen people, plus at least one extra cook, expanded crew quarters, greater food costs, and other hidden increases, just to accommodate your larger crew. Look at the M/V _[Maersk Alabama](http://en.wikipedia.org/wiki/MV_Maersk_Alabama)_ (a diesel merchant ship I could name off the top of my head) as standard - she has a _total_ crew of 21. You’re nearly doubling your crew size to switch to steam. That’s going to really cause a jump in overhead costs. > > Then there’s maintenance. Steam is a nasty bitch to deal with. It cuts metal, as well as other substances. It also means that your surfaces are all going to be covered in moisture, which is a great medium to promote corrosion. Even with a properly conditioned steam plant corrosion and wear are constant battles, requiring a lot more maintenance than a diesel plant does. Let even a little contamination get into your steam plant and the corrosion rates go through the roof. Which leads to the whole safety issue: steam kills. Diesel plants can be deadly, no question about that, but you don’t hear about diesel plants blowing up and cooking their whole crews. Steam explosions are a lot more common than any one wants to think about. I was active duty when the [_Iwo Jima_ LPH-2](http://en.wikipedia.org/wiki/USS_Iwo_Jima_%28LPH-2%29#Catastrophic_Boiler_Accident) cooked a whole watch standing crew. On the one hand, you can say that the accident was the result of a botched valve replacement, but the potential for that sort of disaster was there with the steam plant which required the more complex and more frequent maintenance than a similar diesel plant would have needed. > > Also touching upon maintenance is that fueling a coal fired boiler plant is going to be more complex than fueling an oil-based boiler plant, let alone a oil-based diesel plant. At the very least you’ll have to have hoppers, conveyor systems, and means to control the coal from shifting at the ship rolls in heavy seas, and to balance the load as coal is burned. In the old days this was often done manually, but that would even further jump up the manning requirements mentioned above. > > The old coal fired steam liners, freighters and tramps have a rosy, and romantic, image these days. You can get me waxing nostalgic about them very easily. But compared to a modern diesel plant they were very expensive to operate. And that, not any environmental regulation, is going to be what keeps them in the past. There is a low of good info here,. On an oil fired merchant steam ship each watch will have a watch officer (a third or second assistant engineer), an oiler, and a fireman. Aa complete black gang crew. Chief, 1st, 2nd two 3rds, three oilers,three firemen, and maybe two wipers plus a possable day third. Total maybe 14 to16. Go coal now add three to six strokers, and posabbly two more wipers (coal dust to clean. Coal bunkers take up a lot move volume than oil tanks. Now to be able to transefer that coal requires large equipment taking up more room. which means less cargo. then there is the handling of ash. If not more personel to handle it more hours. Long time shince I shipped but I believe the Snipes on a modern ship number under 10. To retro fit a ship. Wow. To convert from diesel to steam would take maybe a year of yard time. the other choice would be to convert the main engines to blast injection (Diesel planed on running his engines on coal). that would mean tearing the engines apart. New heads, new cam shaft, new injectors, less Hp from the same engines. It would never be the smart thing to do. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [December 21, 2009, 5:24pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/22 "2009-12-21T17:24:34Z")
What about an electric ship? Coal- or nuclear-fired power plants at the points of origin, possibly used to charge interchangeable batteries (since presumably charging fixed batteries would take something like weeks). I assume that the weight of a battery pack that would be required to power a ship would be significantly lower than the weight of however many tons of diesel fuel or coal would be required. I also assume that an electric motor (or, more likely, several hundred electric motors) would be inherently more efficient and more reliable than either a diesel engine or a coal-fired steam turbine. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [December 21, 2009, 5:27pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/23 "2009-12-21T17:27:42Z")
> [@Really\_Not\_All\_That\_Bright](#): > > I assume that the weight of a battery pack that would be required to power a ship would be significantly lower than the weight of however many tons of diesel fuel or coal would be required. That’s a really bad assumption. The energy density of even the best batteries is far, far lower than Diesel fuel. This is one of the reasons that electric cars aren’t commonplace. ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [December 21, 2009, 5:30pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/24 "2009-12-21T17:30:07Z")
> [@Really\_Not\_All\_That\_Bright](#): > > What about an electric ship? […] > > I assume that the weight of a battery pack that would be required to power a ship would be significantly lower than the weight of however many tons of diesel fuel or coal would be required. Why would you assume that? One of the practical disadvantages of of electric cars v. comventional gasoline or diesel vehicles is that the energy density of a battery pack is far les than that of a tankfull of fuel, and teh batteries weigh far more. Marine applications would have similar disadvantages, only writ much larger. ETA: what **beowulff** said. ---
**Author:** ![OtakuLoki](https://avatars.discourse-cdn.com/v4/letter/o/ac8455/32.png) [@OtakuLoki](https://boards.straightdope.com/u/OtakuLoki)\ **Post date:** [December 21, 2009, 5:37pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/25 "2009-12-21T17:37:47Z")
> [@Really\_Not\_All\_That\_Bright](#): > > What about an electric ship? Coal- or nuclear-fired power plants at the points of origin, possibly used to charge interchangeable batteries (since presumably charging fixed batteries would take something like weeks). > > I assume that the weight of a battery pack that would be required to power a ship would be significantly lower than the weight of however many tons of diesel fuel or coal would be required. I also assume that an electric motor (or, more likely, several hundred electric motors) would be inherently more efficient and more reliable than either a diesel engine or a coal-fired steam turbine. To offer some more supporting evidence: If this battery pack idea were feasible I think it would be one of the technologies being experimented with for advanced AIP\* plants for coastal submarines. AFAIK none of the AIP boats being built or considered are talking about being electric with external power generation. Now, the fuel cell plants that are currently in production may have the power density to replace a diesel plant, I don’t know the details of any of those plants, so I can’t speak to them. Having said that, I suspect that what’s acceptable for a relatively inexpensive submarine may well prove to be too much of a capital investment for a cargo hauler. Military ideas of cheap aren’t often shared by civilian accountants. \*Air Independent Propulsion or Plant ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [December 21, 2009, 5:39pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/26 "2009-12-21T17:39:08Z")
> [@beowulff](#): > > That’s a really bad assumption. > The energy density of even the best batteries is far, far lower than Diesel fuel. This is one of the reasons that electric cars aren’t commonplace. Oh, duh. Didn’t even think of that. What about a hydrogen fuel cell? Plenty of water to work with… ---
**Author:** ![pan1](https://avatars.discourse-cdn.com/v4/letter/p/e495f1/32.png) [@pan1](https://boards.straightdope.com/u/pan1)\ **Post date:** [December 21, 2009, 5:44pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/27 "2009-12-21T17:44:56Z")
> [@Really\_Not\_All\_That\_Bright](#): > > Oh, duh. Didn’t even think of that. > > What about a hydrogen fuel cell? Plenty of water to work with… Or wind power… Odd as it sounds, wind powered ships(sails) may make a comeback before coal does. The technology for sailing has improved quite a bit since steam took over. A weak solar powered engine would keeps ships moving when the wind is lacking. Hydrogen fuel cells still require quite a bit of power to seperate the hydrogen from the water. Water is the exhaust, not the fuel. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [December 21, 2009, 5:55pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/28 "2009-12-21T17:55:57Z")
> [@Really\_Not\_All\_That\_Bright](#): > > What about a hydrogen fuel cell? Plenty of water to work with… Hydrogen made by electrolysis of water is far more expensive than current commercial sources of hydrogen, which is made from natural gas. If I owned a ship with a hydrogen fuel cell, why would I buy your expensive fuel when I can get it cheaper elsewhere? ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [December 21, 2009, 6:46pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/29 "2009-12-21T18:46:07Z")
Well, it comes with a lovely set of steak knives. ---
**Author:** ![Dog80](https://avatars.discourse-cdn.com/v4/letter/d/6bbea6/32.png) [@Dog80](https://boards.straightdope.com/u/Dog80)\ **Post date:** [December 21, 2009, 8:22pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/30 "2009-12-21T20:22:33Z")
Is a gasifier setup more efficient than steam power? Besides with some small scale modifications you can still use the diesel engine with both fuels. ---
**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\ **Post date:** [December 21, 2009, 8:55pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/31 "2009-12-21T20:55:25Z")
In addition to the other disadvantages, coal is dangerous-the dust can explode, and spontaneous combustion can take place in a coal bin. Such incidents happened a lot in the pre-oil age, and quite a few unexplained ship losses were probably caused by coal dust explosions. ---
**Author:** ![Really\_Not\_All\_That\_Bright](https://avatars.discourse-cdn.com/v4/letter/r/e8c25b/32.png) [@Really\_Not\_All\_That\_Bright](https://boards.straightdope.com/u/Really_Not_All_That_Bright)\ **Post date:** [December 21, 2009, 9:08pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/32 "2009-12-21T21:08:33Z")
You don’t think diesel explodes? That’s how combustion works. ---
**Author:** ![mlees](https://avatars.discourse-cdn.com/v4/letter/m/ba8739/32.png) [@mlees](https://boards.straightdope.com/u/mlees)\ **Post date:** [December 21, 2009, 9:52pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/33 "2009-12-21T21:52:08Z")
On the subject of steam-to-electric ships (turboelectric), the US Navy played around with that in the twenties: > **[History and Technology - Turboelectric Drive in American Capital Ships -...](http://www.navweaps.com/index_tech/tech-038.php)** > [@](#): > > Turboelectric drive was a unique and elegant solution to the propulsion and range problems faced by the US Navy in the 1920s and 1930s. It performed well, and permitted a minute form of subdivision that rendered ships fitted with it highly resistant to torpedo damage. On the whole, it was a success and a good investment, abandoned only because of the cost in weight and money in an environment of Treaty limitations and later in an environment in which no limits mattered. The whole article is more detailed, but I don’t want to quote enmasse. But note that this was an oil fired ship design, generating electricity to turn the props, not a coal design. I presume using coal would involve more precious ship space and weight, all of which translates to money on a commercial ship. ---
**Author:** ![gazpacho](https://avatars.discourse-cdn.com/v4/letter/g/6f9a4e/32.png) [@gazpacho](https://boards.straightdope.com/u/gazpacho)\ **Post date:** [December 21, 2009, 10:07pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/34 "2009-12-21T22:07:50Z")
> [@Really\_Not\_All\_That\_Bright](#): > > You don’t think diesel explodes? That’s how combustion works. You have to go to a fair amount of work to get it to explode. You have to vaporize it and get the air vapor mixture hot. It is easier to handle diesel in a way that vapors don’t build up. Dust is a hazard even for things that are not burnt for heat. Dust suppression is a be issue with handling grain. ---
**Author:** ![Snnipe\_70E](https://avatars.discourse-cdn.com/v4/letter/s/b5a626/32.png) [@Snnipe\_70E](https://boards.straightdope.com/u/Snnipe_70E)\ **Post date:** [December 22, 2009, 2:51am UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/35 "2009-12-22T02:51:52Z")
> [@Dog80](#): > > Is a gasifier setup more efficient than steam power? Besides with some small scale modifications you can still use the diesel engine with both fuels. The modifications would not be small. Coal does not pump. Cargo space would have to be converted to coal bunkers. Arcameties screws from the new fuel bunkers would have to be installed. Means of handeling the ash would have to be added. and on a diesel large blast injection air compressors would have to be added. The engine would have to be bare boned to change the camshaft. New heads on each cylinder mounted. And there would be much more. ---
**Author:** ![Princhester](https://avatars.discourse-cdn.com/v4/letter/p/3e96dc/32.png) [@Princhester](https://boards.straightdope.com/u/Princhester)\ **Post date:** [December 22, 2009, 12:36pm UTC](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894/36 "2009-12-22T12:36:12Z")
To add some information to the speculation, there were four modern (early 70’s) coal fired ships on the Gladstone - Weipa run in Qld for about 30 years, just retiring. (the River Embley, the River Boyne, the Endeavour River and the Fitzroy River). They were all about 50,000 GRT. By the end of their life they had crews of 19, which is no more than on oil fired ships. They were very reliable. They had fully automatic engine rooms and were UMS (Unmanned Machinery Space) certified. So much for speculation above. They were purpose built and yes they did have to have a larger space dedicated to a coal bunker. Their range was short by comparison to oil fired vessels otherwise comparable. They were built at the time oil prices were high. They were also (very importantly) built in the knowledge they would be servicing ports that (as it happened) were also coal ports so that coal was cheap and available. They needed dedicated bunkering wharves for reasons others have outlined. So modern efficient coal fired vessels are possible. At least based on what I know they are not as flexible as oil fired vessels. The broader economic questions I will leave to others. [Previous page](https://boards.straightdope.com/t/how-high-should-oil-prices-get-for-sea-shipping-to-switch-to-coal-can-this-realistically-happen/521894.md?page=1)