Boatnerd Discussion Forum

by **Guest** » July 2, 2020, 8:31 am

There is indeed a considerable increase in fuel consumption at the top end of the speed range for the ship, almost double for the last 1 or 2 knots. Therefore to save fuel and so on it is often advisable to operate at a lower speed. However that doesn't explain why they are taking the scenic route around Lake Superior - the weather forecast is fine. The extra miles steaming will eat up most if not all of the fuel saved by running more slowly. I wonder why they don't just sail on down at their most economic speed and then go to anchor or tie up and shut the engines down completely.

by **Guest** » June 29, 2020, 2:26 pm

Are ships designed with power and hull forms to have something like a an optimum cruising speed? Wouldn't this be the balance between of going too slow a ship would cover less of a distance in comparison to its fuel burn and going too fast would increase fuel burn and lower range? I know aircraft are built to such design parameters and I believe cars are also, but I'm not sure about ships.

by **Guest** » June 29, 2020, 2:17 pm

Guest wrote:I wonder if they need pellets on demand rather than stockpiling, cause the most sense still would be to deliver the X amount of pellets the contract calls for then layup

There may be some question as too the amount of pellets that will be needed due to fluctuating demand. Putting a ship into layup and then returning it to service can be an expensive process.

by **navarch** » June 29, 2020, 10:50 am

Bob wrote:Even though the cort is running checked down on its runs lately to save fuel aren’t they using more fuel with the longer route that they have been running instead of taking the shorter route running checked down. I realize they are trying to extend the trip so they can keep running. Sorry to keep beating this thread to death but just curious to the thought process here.

The speed fuel/curve for ships is not linear but exponential (that is, at higher speeds it takes a lot more fuel to go an extra one mph than it would to go an extra one mph at lower speeds). So even a small reduction in speed could easily makeup for the extra trip time, especially if the vessel would have to end up waiting at the dock to load/unload if arriving early. Additionally, as one other poster/crew mentioned, they took one or more engines offline which saves fuel as well as wear and tear on engines.

by **Guest** » June 29, 2020, 9:10 am

I wonder if they need pellets on demand rather than stockpiling, cause the most sense still would be to deliver the X amount of pellets the contract calls for then layup

by **Guest** » June 29, 2020, 7:44 am

Bob wrote:Even though the cort is running checked down on its runs lately to save fuel aren’t they using more fuel with the longer route that they have been running instead of taking the shorter route running checked down. I realize they are trying to extend the trip so they can keep running. Sorry to keep beating this thread to death but just curious to the thought process here.

Here is a simplistic explanation, and something I did yesterday when I found out we would have a four hour delay at the loading dock:

120 miles to get to the loading dock. At 12 mph burning 400 gph we would consume 4000 gals of fuel.
I took one of the two engines offline and made 9 mph. So it took 13.3 hrs to get to the dock burning 200 gph. Burned 2660 gals of fuel and saved 1340 @ $2 a gallon, or saved the company $2680.
Didn't have the expense of a two hour crew call out for tying up early either!

by **GuestfromEU** » June 29, 2020, 6:26 am

Bob wrote:Even though the cort is running checked down on its runs lately to save fuel aren’t they using more fuel with the longer route that they have been running instead of taking the shorter route running checked down. I realize they are trying to extend the trip so they can keep running. Sorry to keep beating this thread to death but just curious to the thought process here.

Fuel consumption is not a linear ratio to speed.

For example, at 12 knots, fuel consumption could be 26 MT/day.

At 6 knots, it is not half (13 MT/day), but possibly 8 or 9 MT/day.

Likewise, at 13 knots, fuel consumption could increase to 30 MT/day.

Those are not numbers for the Stewart J. Cort - they are only examples. The only value which is "fixed" is fuel consumption in grams per kilowatt-hour or brake horsepower-hour.

by **Bob** » June 28, 2020, 11:46 pm

Even though the cort is running checked down on its runs lately to save fuel aren’t they using more fuel with the longer route that they have been running instead of taking the shorter route running checked down. I realize they are trying to extend the trip so they can keep running. Sorry to keep beating this thread to death but just curious to the thought process here.

by **Guest** » June 23, 2020, 2:00 pm

Sure can tell not much is happening at this point in the season when this subject, which has a reasonable explanation, garners so much attention! I remember living through the dark days of the 1980s and the current level of ship traffic (US & Canadian) surely reminds me of those times. Hopefully some of those laid up ships and their crews will return to work soon.

by **Bob** » June 22, 2020, 11:14 pm

Stands to reason that the cort is taking her time as they pulled the burns harbor off of the run from superior to burns harbor and she has done about 4 trips from two harbors to Indiana Harbor, so they must be pretty full of pellets at burns which is why the cort has been dragging her feet so she can keep running instead of going into layup. I see the James r barker is doing a load from Duluth to burns harbor which seems a little unusual as the loads to burns come out of superior or occasionally two harbors.

by **GuestfromEU** » June 21, 2020, 9:15 pm

RogerKYS wrote:Guest is correct

"Not sure how many times it has to be answered that they're running in economy mode. If she runs at full speed, there aren't going to be pellets for her, and she's just going to end up laying up early. Mittal is trying to fulfill the full season of charter."

They are steaming at slow speed, or eco speed, to reduce fuel consumption. This also increases round trip time, allowing for loading and delivery of cargo at greater intervals. Nothing unusual. This has been done for 15+ years with ocean-going container ships and oil tankers. Often it can be more economical to sail several ships this way compared to fewer ships at full speed. Both Mittal and Interlake have an interest in reducing operating costs, with fuel being the one aspect both parties can control.

by **Mr Link** » June 21, 2020, 9:10 pm

I think they call it "slow steaming" on the oceans.

by **BigRiver** » June 21, 2020, 9:00 pm

Guest is correct

"Not sure how many times it has to be answered that they're running in economy mode. If she runs at full speed, there aren't going to be pellets for her, and she's just going to end up laying up early. Mittal is trying to fulfill the full season of charter."

by **Guest** » June 21, 2020, 8:59 pm

Denny wrote:As of 2:45 p.m. on June 21st, the Cort is way up in Lake Superior and running on a very odd and strange course again headed downbound. Sure can’t figure this one out?

Not sure how many times it has to be answered that they're running in economy mode. If she runs at full speed, there aren't going to be pellets for her, and she's just going to end up laying up early. Mittal is trying to fulfill the full season of charter.

by **Guest** » June 21, 2020, 8:24 pm

Darryl wrote:The loading dock in Superior gets ore from two taconite plants that are not doing a whole lot right now. That has to be put into the equation.

Probably loading off the stockpile. Shouldn't have anything to do with the speed and course of the Cort.

by **Denny** » June 21, 2020, 1:54 pm

As of 2:45 p.m. on June 21st, the Cort is way up in Lake Superior and running on a very odd and strange course again headed downbound. Sure can’t figure this one out?

by **Darryl** » June 21, 2020, 11:52 am

The loading dock in Superior gets ore from two taconite plants that are not doing a whole lot right now. That has to be put into the equation.

by **Guest** » June 20, 2020, 1:15 pm

Blast furnace "D" is in operation, but blast furnace "C" was placed into a two-week maintenance period starting April 17. Anyone know if this is still continuing?

by **hausen** » June 20, 2020, 10:33 am

Bob wrote:What is going on with the cort? Once again she’s hugging the north shore and going 6.2 knots,very odd as there’s no weather and all the other ships are in the middle of the lake.

She's been running slow and taking near-shore routes for weeks. Seems like it must be a conscious decision to balance fuel consumption and the number of trips she has to make this season to meet cargo carriage requirements.

by **Guest** » June 20, 2020, 9:54 am

guest wrote:my guess is that there is a problem of some sort aboard that the coast guard or possibly the office has required them to stay within a certain distance from shore and use a reduced speed. Most likely problem would be a mechanical but who knows.

If there was a problem with a ship that required it to stay within a certain distance of shore its more likely it would have received at least temporary repairs before leaving port or would have headed to a shipyard rather than continue to operate in a seemingly normal fashion with the exception of running at a reduced speed over a more lengthy course. If there was a serious issue that required interaction with the Coast Guard I doubt the Cort would have been allowed to load a cargo. This is more likely just a way to increase the voyage time to prevent the ship being put into layup due to soft demand. Remember the Cort only unloads at one port so there may also be some scheduling or mechanical issues at Burns Harbor that is prompting this situation. I think people are starting to read too much into this.

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