# Rowing an oil tanker **URL:** \ **Category:** Factual Questions\ **Created:** [April 2, 2002, 8:30am UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359 "2002-04-02T08:30:19Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![bryanmaguire](https://avatars.discourse-cdn.com/v4/letter/b/d07c76/32.png) [@bryanmaguire](https://boards.straightdope.com/u/bryanmaguire)\ **Post date:** [April 2, 2002, 8:30am UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/1 "2002-04-02T08:30:19Z")
I was watching waterworld again last night (its going to a cult classic, just you mark my words) and the scene where they start rowing the Exxon Valdez ala a roman galley got me thinking. Would it really be possible to row an oil tanker in the manner shown? Assuming the oars were properly anchored and sufficiently strong to take the strain. How many people would you need? ---
**Author:** ![Milton\_De\_La\_Warre](https://avatars.discourse-cdn.com/v4/letter/m/e480ec/32.png) [@Milton\_De\_La\_Warre](https://boards.straightdope.com/u/Milton_De_La_Warre)\ **Post date:** [April 2, 2002, 12:07pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/2 "2002-04-02T12:07:57Z")
I don’t have the final answer, but… Empty tanker or full? The weight difference is immense. Stopping and steering it would be at least as difficult as getting it into motion. Getting it into motion would be the most difficult part. Once underway, the momentum would tend to be of some assistance to the crew of rowers. Some engineering type may correct me, but I would think it more mechanically efficient if the crew expended its efforts on somehow working cranks to turn the ship’s propeller manually. I also opine here that the effects of the wind and currents on the huge hull would be greater than a crew of rowers could overcome. The shp would likely go where it wanted to, and the crew would spend their efforts in attempts to counteract this. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [April 2, 2002, 12:27pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/3 "2002-04-02T12:27:27Z")
What **JCHeckler** said. It would be more efficient to try and turn the screw, and with something that large, wind and wave are an enormous drag - sorta like _Waterworld_ itself. ---
**Author:** ![bryanmaguire](https://avatars.discourse-cdn.com/v4/letter/b/d07c76/32.png) [@bryanmaguire](https://boards.straightdope.com/u/bryanmaguire)\ **Post date:** [April 2, 2002, 12:40pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/4 "2002-04-02T12:40:58Z")
If i remember correctly it was nearly empty. They were down to their last 4’9" of crude oil. You’re probably right that turning the screw would be easier but in the film they rowed so thats what I’m interested in. ---
**Author:** ![Popup](https://avatars.discourse-cdn.com/v4/letter/p/94ad74/32.png) [@Popup](https://boards.straightdope.com/u/Popup)\ **Post date:** [April 2, 2002, 2:57pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/5 "2002-04-02T14:57:12Z")
I have to go against the current here - so to speak. I think it’s easier for a small amount of people to row a large boat using oars. At low speed it is a relatively efficient way of transfering power. If the waterline is manned with people with oars they can probably put in about 500W each (for a short time) and almost all of that power would be transfered into moving water. (Remember that rowing uses almost all muscle groups) The alternative would probably have involved some kind of stationary bikes with the pedals connected through the gearbox. Then you will be faced with the losses in the gearbox which will probably be enormous if it hasn’t been properly lubricated and maintained. Then the propeller will churn the water in only one location, which will create more eddy-currents than a continuous waterline-full of oars. I believe that would be counter-productive. If you manage to overcome the problems with the gearbox, and have an infinite supply of material, time and would-be oarsmen it would no doubt be favourable to fill the entire hull of the ship with pedaling people, but assuming normal apocalyptical conditions I’d go for the low-tech oars. NB I haven’t seen the film, so I’ve got no idea how they did it. I’m only saying that I’d cut holes just above the waterline and put loads of oarsmen all-over. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [April 2, 2002, 3:48pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/6 "2002-04-02T15:48:46Z")
Actually human muscles work better when they are moving. Pushing a very slow-moving oar of a galley is not an efficient use of muscles. On a bicycle, the optimal cadence (pedal spinning speed) is thought to be around 80 to 90 rpm. Any slower or faster and you lose efficiency. Gasoline engines are like that too - not much torque at very low rpm, and redlining it isn’t very efficient either. Also oars need to be lifted out of the water and moved back for the next stroke. Additional energy losses there. As for the OP, one person can row a boat, say, 10 ft long and 3 ft wide? The Valdez is about 100 times longer and 50 times wider. If the resistance is proportional to the area (which I am not at all sure about), then you need 5000 people to move the Valdez. I’m sure someone with better knowledge of fluid dynamics will jump in and give a more valid estimate. ---
**Author:** ![Shortie](https://avatars.discourse-cdn.com/v4/letter/s/ecd19e/32.png) [@Shortie](https://boards.straightdope.com/u/Shortie)\ **Post date:** [April 2, 2002, 5:25pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/7 "2002-04-02T17:25:29Z")
> [@](#): > > \*Originally posted by Popup \* > **I have to go against the current here - so to speak. I think it’s easier for a small amount of people to row a large boat using oars. At low speed it is a relatively efficient way of transfering power. If the waterline is manned with people with oars they can probably put in about 500W each (for a short time) and almost all of that power would be transfered into moving water. (Remember that rowing uses almost all muscle groups)** Not galley-style rowing, there it’s arms and backs only. The efficiency is hence actually pretty poor. I suppose you could try and put in sliding seats to use the legs, but with oars that big, that many people, and all the gunk inside the ship I really wouldn’t like to try it. I’m not sure the idea of moving it by muscle power is at all practical, but maybe some kind of paddle wheel set up and treadmills to power them might work. (You could stick with the original screw or use bikes, but that’s more complicated) ---
**Author:** ![Sofa\_King](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@Sofa\_King](https://boards.straightdope.com/u/Sofa_King)\ **Post date:** [April 2, 2002, 6:16pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/8 "2002-04-02T18:16:25Z")
I think that in nautical terminology, when you’re talking about oars of the size proposed to propel an oil tanker, they are called _sweeps_. I don’t know exactly how large the longest historical sweeps were, but I do know that some frigates were outfitted with them in the Napoleonic wars. In July of 1812 the becalmed U.S.S. _Constitution_ was [nearly overtaken](http://www3.teleplex.net/timonier/shiplogs/log04.html) by two pursuing British frigates, one of which was employing sweeps. I’m not sure about this, but I think the standard 32-gun frigate was the largest seagoing vessel ever to be regularly outfitted with sweeps. They’re pretty big ships, but you could probably mount one as a hood ornament on an oil tanker. Anyway, I thought that mentioning the terminology might help some of you in your searching. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [April 2, 2002, 6:45pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/9 "2002-04-02T18:45:44Z")
I cannot see any practical way to row a tanker but I’l give some related information. To begin with we have to assume _absolute_ calm. And i do mean _absolute_ as the slightest breeze or current would make the task absolutely impossible. In the days of sail, when a ship was becalmed just a few miles from its destination port the standard procedure was to put down the boat, fill it with men, and tow the ship. Figures are difficult to give but you would need anywhere between 8 to 20 men in one or two boats to tow the ship at under a knot. The job was backbreaking. Compare the displacement and you get an idea of what it might take to move a tanker. Note that the power required is related to speed so if _any_ speed would do, then one person could theoretically move a tanker. In practice, the slightest breeze or current would make it impossible even for a large group. ---
**Author:** ![racer72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/racer72/32/3075_2.png) [@racer72](https://boards.straightdope.com/u/racer72)\ **Post date:** [April 2, 2002, 7:26pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/10 "2002-04-02T19:26:22Z")
All ships are rated by how much water they displace in weight. A ship like the Exxon Valdez dispaces around 115 metric tons of water empty. To row the EV, you would need enough strength in the rowers to offset the weight first. An average rower could probably row approximately 500 pounds for one hour before becoming overly tired. You would require 230,000 rowers to move the EV. I served on the USS Sperry, a submarine tender when I was in the Navy, it displaced a modest 24 metric tons and the output from the single screw was rated at 32 ton/hours. This gave the ship a top speed of a whopping 18 mph for short periods of time. Even back in the times of the Vikings when oar power was common, ships have very little displacement to offset the drag of the water. And a long ship back then might be 75 feet long. In real life, if would be impossible to row a ship like the EV. ---
**Author:** ![David\_Simmons](https://avatars.discourse-cdn.com/v4/letter/d/9de053/32.png) [@David\_Simmons](https://boards.straightdope.com/u/David_Simmons)\ **Post date:** [April 2, 2002, 7:42pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/11 "2002-04-02T19:42:02Z")
> [@](#): > > \*Originally posted by bryanmaguire \* > \*\*I was watching waterworld again last night (its going to a cult classic, just you mark my words) and the scene where they start rowing the Exxon Valdez ala a roman galley got me thinking. Would it really be possible to row an oil tanker in the manner shown? Assuming the oars were properly anchored and sufficiently strong to take the strain. How many people would you need? \*\* I suppose you could go downwind and with the current pretty well. ---
**Author:** ![justinh](https://avatars.discourse-cdn.com/v4/letter/j/9fc29f/32.png) [@justinh](https://boards.straightdope.com/u/justinh)\ **Post date:** [April 2, 2002, 8:56pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/12 "2002-04-02T20:56:47Z")
what is warping ? as in “At 7 AM got out a kedge and warped the ship ahead. At 8 AM calm, employed warping and towing the ship ahead” ---
**Author:** ![The\_Flying\_Dutchman](https://avatars.discourse-cdn.com/v4/letter/t/9fc348/32.png) [@The\_Flying\_Dutchman](https://boards.straightdope.com/u/The_Flying_Dutchman)\ **Post date:** [April 2, 2002, 10:07pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/13 "2002-04-02T22:07:48Z")
The lines used to tie yachts to a dock are sometimes called warps. In simple woven fabrics the longitudinal thread is called the **warp** and the transverse threads the **weft** Your quote seems to describe **sailor’s** scenario during calm near port. ---
**Author:** ![hibernicus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hibernicus/32/2802_2.png) [@hibernicus](https://boards.straightdope.com/u/hibernicus)\ **Post date:** [April 2, 2002, 10:09pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/14 "2002-04-02T22:09:58Z")
Warping is a laborious way of moving a ship forward through the ice by hauling on a rope that’s anchored in the ice a short distance ahead. ---
**Author:** ![hibernicus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hibernicus/32/2802_2.png) [@hibernicus](https://boards.straightdope.com/u/hibernicus)\ **Post date:** [April 2, 2002, 10:14pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/15 "2002-04-02T22:14:06Z")
> [@](#): > > \*Originally posted by racer72 \* > **All ships are rated by how much water they displace in weight. A ship like the Exxon Valdez dispaces around 115 metric tons of water empty. To row the EV, you would need enough strength in the rowers to offset the weight first. […] You would require 230,000 rowers to move the EV.** This is absolutely true, if the rowers are trying to move the ship vertically upwards. If, however, they want to move the ship along the surface of the water, they have no weight to overcome, and a single rower will be able to move the ship, albeit imperceptibly slowly. ---
**Author:** ![AndrewL](https://avatars.discourse-cdn.com/v4/letter/a/3d9bf3/32.png) [@AndrewL](https://boards.straightdope.com/u/AndrewL)\ **Post date:** [April 2, 2002, 10:35pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/16 "2002-04-02T22:35:37Z")
> [@](#): > > \*Originally posted by hibernicus \* > \*\* > If, however, they want to move the ship along the surface of the water, they have no weight to overcome, and a single rower will be able to move the ship, albeit imperceptibly slowly. \*\* Assuming there’s no wind and no water currents to deal with, yes. In practice a boat needs a certain level of power so as to not be totally at the mercy of the elements to move it around. The question is whether a handful of men with oars is going to make any meaningful difference to a ship that size against the forces of water and wind currents pushing it around. ---
**Author:** ![Fish\_Cheer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fish_cheer/32/17179_2.png) [@Fish\_Cheer](https://boards.straightdope.com/u/Fish_Cheer)\ **Post date:** [April 2, 2002, 11:53pm UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/17 "2002-04-02T23:53:58Z")
No way. Have you ever had the chance to see the engine room of a reasonably large ship, e.g. a channel ferry? I can’t believe that any group of rowers could ever come close to this “vulgar display of power”. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [April 3, 2002, 12:24am UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/18 "2002-04-03T00:24:41Z")
Quoth **sailor** : > [@](#): > > In the days of sail, when a ship was becalmed just a few miles from its destination port the standard procedure was to put down the boat, fill it with men, and tow the ship. I had understood that the procedure was for the boat to carry an anchor some distance in front of the ship, and drop it. The anchor below the ship was then raised, and the anchor ahead drawn in until the ship was above it, at which point the process would be repeated. Was this an actual procedure, and if so, when would it have been used, versus direct towing? ---
**Author:** ![Tranquilis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tranquilis/32/3639_2.png) [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)\ **Post date:** [April 3, 2002, 12:25am UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/19 "2002-04-03T00:25:09Z")
A “kedge” is an anchor. “Kedging & warping” is the process of hauling an anchor out ahead of the ship by small boat (“cutter”), dropping it, and then winching in the anchor cable (“warping”), pulling the vessel towards the anchor. This is classically done with two kedges at a time, one being warped in whie the other is beeing hauled out ahead of the ship. It’s laborous and slow, used only in desperation. Sweeps could concieveably move the EV, but, as others have noted, only in conditions of absolute calm. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [April 3, 2002, 12:51am UTC](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359/20 "2002-04-03T00:51:35Z")
\>\> All ships are rated by how much water they displace in weight. A ship like the Exxon Valdez dispaces around 115 metric tons of water empty. Ummm, you might want to check your numbers or your units or your sense of numbers and magnitudes… or something. Kedging was, and is, done, among other circumstances, when a boat runs aground and thinks they can get out of that situation that way. I have to admit I have had to do it on my own boat a couple of times. That’s what happens when you’re not paying attention. Kedging only makes sense for a very short distance and when you need great force. It is just not practical to kedge your way for miles. But if you are on a sandbar maybe a short tug will get you off it. [Next page](https://boards.straightdope.com/t/rowing-an-oil-tanker/101359.md?page=2)