Age of Sail May Not Be Dead

[Doodles]

Who would have predicted this turnabout?

Mish's Global Economic Trend Analysis: Slow Speed Ahead: Cargo Ships Travel Slower Today Than 130 Years Ago

[maxingout]

Slower speeds are a great idea and a sensible way to instantly save large amounts of fuel.

I remember years ago when we had the first fuel crisis that highway speeds were dropped to 55 miles per hour. It created an instant savings in energy costs all around.

I don't understand why the speed limit on cars and trucks is 70 to 75 mph, when you could have a massive and instant saving on energy costs by dropping the speed limit to 55.

I don't think that most people really are interested in being "green" as they zip by at seventy miles per hour.

Even if you are driving a fuel efficient vehicle, you still save the environment by driving 55 mph.

I am glad to hear that shipping is making this move. I wish the same thing would happen with cars.

[TaoJones]

As I remember it, Dave, it was the trucking industry that lobbied hard for raising the speed limits back up to 70 / 75 mph (or no limit at all in certain parts of the West) because the fuel / energy savings from driving at a maximum of 55mph was trivial compared to the greater costs incurred as a result of the extra time required to deliver goods at slower speeds. Shippers of cargo via the oceans and seas might be expected to make that same argument.

Not mentioned in your analysis was the reduction in deaths from auto accidents when the limit was lowered to 55 (double nickels in the truckers parlance). It's conceivable to me that slower speeds for cargo vessels could also save lives on the water, as the running-down of slower vessels by the behemoths could, potentially, decrease.

Of course, if they're not keeping watch now, it's unlikely they'll be any more attentive at reduced speeds, and it's the lack of looking out for others that is the primary reason smaller craft are run down, not just the speed.

TaoJones

[Healer52]

People still drive 70 or 75 these days, where the limit is 55. All it does is generate revenue for government. Same back in the 70's. The numbers on lives saved are pretty suspect, as are the numbers on fuel economy.

[yotphix]

The numbers on lives saved are pretty suspect, as are the numbers on fuel economy.

???Are you serious? Do the math. You will use less fuel travelling at 55 than you will at 70. The force of wind increases exponentially with speed. More of the energy that you are using will go into defeating moving air aside to let you through as you go faster. Nothing suspect about that.

I can't speak to the numbers on lives saved or lost but the same truths would apply with respect the the force of your head contacting hard things at higher speeds.

[Ex-Calif]

I just did an LA to SFo drive. If you ain't going 80 you are a moving speed bump...

[Drew13440]

The 55 mile an hour speed limit was imposed in the '70's during the oil crisis. On American interstate highways, it had virtually no impact on safety. Automobiles, generally, are most fuel efficient at about 30 mph. Efficiency is reduced marginally to about 55 mph, above which fuel efficiency drops dramatically. It may be a little better with modern engines, but the 55 limit was meant to save fuel and that's it.

Congress repealed the 55 limit in the 1990's when gasoline was below a dollar a gallon. When the government decrees that responsible use of any commodity is no longer necessary, invest in that commodity - the price is going up!

The shippers are under pressure right now and will do what they must to keep costs down. It's great, environmentally, but don't hold your breath when demand for their services (and prices) go back up.

FWIW, I figured out for myself that easing the throttle has a huge impact on fuel usage. I hate motoring, but so what if I'm out there a little longer?

[yotphix]

I work on a big motor yacht and if we fill our tanks with diesel, approx 5000gal, we can 'cruise' about 400 NM at 18 knots. When we run at 10 knots we can stretch that to over 1000 NM. On a trip from California to Florida we get there sooner since we don't have to stop (and clear in) for fuel so often. In fact, we might not get there at all if we burn it fast since there aren't necessarily fueling facilities at every little harbour in central america.

[Drew13440]

There you have it, yotphix! Slow down, go further, cheaper.

[David_Old_Jersey]

Originally Posted by Drew13440

There you have it, yotphix! Slow down, go further, cheaper.

In Afghanistan the average vehicle speed is under 55. When you include the Donkeys.

But it was the same in the West. back in the 14th Century. It was also nice and green back then - that's what things are like living in a medieval economy.

I'm voting for staying in the 21st Century

[anjou]

The roads in the UK are so clogged up its a luxury to travel at the legal limit

[Tallswede]

Modern automobiles are much more efficient than the ones we were driving back when the 55mph limit was imposed. With over-drive transmissions cars now get better mph @ 55-60 mph than at 40 where their engines are lugging and transmissions are dropping out of overdrive. Boats are much like the older cars. the "gearing" or prop pitch is set for efficiency at a certain speed. Trying to push it too fast causes too much drag or too much revving and fuel mileage goes down.

Kevin

[Drew13440]

Cars don't get "better" mileage at 60 mph relative to 40. The marginal drop has improved, sure, but physics is physics, still. The time/cost/environmental return at moderate speed has not changed that much. Read OP's link.

[Tallswede]

My vehichles do get better at 60 because they will not stay in O.D. at 40 mph. Many cars with auto trannies are this way. You can't just go by theoretical physics, you have to look at real world applications just like any other situation. I suppose, if you had a perfectly level or slightly downhill road all the time with no weather interferance you might do it. I did read the OP and it was what piqued my interest. I found a website last year called www.cleanmpg.com and have learned a great deal about driving to maximize mpg. I applied this to a recent 3500 mile road trip and amazed myself at the mpg I was able to get in my Dodge Magnum.

Kevin

[Drew13440]

Tallswede, I said 30, not 40 when I started. And there is no way in heck your vehicle is getting "better" mileage at 60 than 40. You've likely got smaller transmission gear wheels than were standard in '70's vehicles, so you're doing better at high speed than we use to. Physics is what it is, even today.

So,