The Ship Model Forum

Michael,

I agree that the cylinders do appear rather small diameter, relative to what you see in later steam engines such as locomotives and marine engines.

However, the small diameter cylinders would operate OK, but they wouldn't generate as much thrust as a larger diameter cylinder with the same steam pressure. Larger diameter cylinders require a greater steam supply (larger boiler, more fuel, etc.). Some of the very early steam engines used small diameter long stroke cylinders. The gearing mechanism creates a lot of mechanical advantage, so small diameter cylinders might work.

Do you know the rotation rate of the Monitor turret? If so, using the gear tooth ratios of the gear system you can calculate the speed the steam cylinders must have operated. From this you can calculate the approximate volume of steam consumed for a given cylinder diameter and length. Is anything known about the pressure or volume of steam produced by the boilers?

Phil

_________________
A collision at sea will ruin your entire day. Aristotle

Here is a photograph of an original Ericsson drawing taken by Adam Winger at the Stevens library. Even with the browning of the 150-year old paper, it is substantially easier to read than the much reduced version of this drawing reproduced in Peterkin's book. This design was drawn by John Ericsson in the fall of 1861. It is kind of a thrill to read the penciled notes made in his hand. This is a photo and not a scan, and the lines may deviate a little, but it is a fairly reliable source document.

The bore and stoke are 16 inches and 12 inches respectively. This is my opinion, based on overlaying CAD lines on the pencil lines and making measurements. The port cylinder has been mirrored into the clear. The cylinder wall dimension reads out as 0.73 inches. I take this to mean 3/4 inches.

Note that the 16 inch stroke and 12 inch bore dimensions are consistent with those used in the next generations of Ericsson monitors, as documented in the Scientific American article referenced above.

Phil, you are right, I have noticed on antique steam tractors that small cylinders can be very potent. (We had a J.I. Case steam tractor one year at our 4th of July parade. It had a steam whistle you could hear for about 8 miles.)

In the case of the USS Monitor, however, I think we can safely extract and rely upon the bore dimensions as depicted in the surviving drawings. On this basis, it looks like the bore diameter was 12 inches.

That early attempt at CAD noted above, with its tiny cyinders, was intended as a schematic representation. The cylinders are out of scale; the gear wheel spokes are wrong; the engine frames are not realistic; and the connecting rod from one cylinder is, oddly, mounted on the axle of the crankshaft. The problem is, that (Intergraph?) drawing is one of the only CAD references to this chunk of machinery, so that its several departures from scale have tended to be reproduced without question by later artists. I think maybe I can see its influence, for example, in the CAD model commissioned by NOVA.

Excellent work Michael,
I'm looking forward to seeing all this come together.

Dean

This is really quite amazing. I love the idea that you will have a working model of the ship when this is all done! Are you planning to do any animations?

Michael,
It seems like there haven't been posts since the summer. How is the work coming? I can provide you with the rotation speed of the turret if that is helpful. I have to look it up, but I have it somewhere. You'll be surprised at how fast it could go
FJD

fjducoin@bellsouth.net

As a follow-up for those interested in the Peterkin book, there has been a new development:

The Internet Archive has digitized "Drawings of the U.S.S. Monitor : a catalog and technical analysis" by Capt. Ernest W Peterkin, USNR (Ret.) using the copy from the State Library of North Carolina, Government & Heritage Library:

http://www.archive.org/details/drawingsofussmon00pete

I'm not entirely sure, but looks as if this was done as part of a larger effort by the State Library of North Carolina to digitize their holdings: http://www.archive.org/details/statelib ... thcarolina

So for those of us wanting to get a look at Peterkin's collection of Montior drawings but without access to the book, this may be a good alternative. The PDF is a bit slow to page through (typical for a scanned/imaged book) but seems to be legible, at least as far as the text itself is concerned.

I copied the Monitor drawings book in PDF format. When I page through I notice that the drawings appear in two stages - first the drawing appears and then it changes. In most cases it seems to become more detailed, but in some cases the drawing disappears on the second pass. Paging back and then returning to the drawing doesn't make it appear again.

Anyone else see this problem?

Phil

_________________
A collision at sea will ruin your entire day. Aristotle

Hmm. Which pages do you see that happen on? Also, which pdf viewer are you using?

I've not been able to look through the whole thing yet - it scrolls very slowly on my machine - but if there are problems with the pdf we could try reporting back to the Internet Archive.

I'm downloading what looks to be the original image data from the contents listed under the All Files link - it's a lot bigger than the pdf, but it may have the individual images representing the misbehaving pages in the pdf.

OK, looks like the best quality images to be had are here (cropped and rotated versions of the original scan images):

http://ia600708.us.archive.org/11/items ... te_jp2.zip

I think they're jpeg2000 images - at any rate, Imagemagick (http://www.imagemagick.org/script/index.php) can convert these to other formats (the tool mogrify is particularly useful for batch image conversion.)

What a super find, Starseeker. It is great that Peterkin is finally being made available again. When you think about the work and scholarship he poured into that book, it is fitting that it is back in circulation, online, in time for the Monitor’s 150th anniversary year.

DuCoin, the project is still progressing. Here is a sketch of the H-frame Ericsson used to support the central spur and pinion. It is a 3D composite from 2 different 2D source drawings. The top view (and dominant dimensions) came from the Stevens collection, the side view came from the Mariners’ Museum. There was a thrust bearing in the middle of the H-frame crossmember. The exact structure of the crankcase is still up in the air. I am thinking it will solve itself as I add other components in and around it.

Great find Starseeker, thanks for the link.

Michael,
Good to see you back on this, it's really a great looking project and I'm looking forward to more.


Dean

starseeker,

Adobe Reader 10.1.2

I don't remember which pages - I just scrolled down into the part of the document with the drawings and paged through for a while.

Phil

_________________
A collision at sea will ruin your entire day. Aristotle

Michael,
Glad to see you are still at work on this, it is an amazing project. I am sure you are aware, but I wanted to mention, that the Mariners' Museum has a full set of full size copy negatives from the Steven's Institute. They can scan these at full size. This is not as good as the originals, which are awesome, but amazing in their detail and information. These are not cheap to get, but sometimes invaluable. They will do this on paper, or send a digital scan. The cost for a digital scan always could be divided among a few interested people.

I will be doing a presentation on the control of the ship and the turret on March 10th at Mariners, during the 150th anniversary of the Battle of Hampton Roads. See http://www.battleofhamptonroads.com/

Would you mind if I used some of your images to demonstrate the turret engines? Of course I would give you full credit for your fantastic work.

Thanks for considering this.

Fran

Hello Francis,

Yes, of course you are welcome to anything here. Note that the V-twin engine is from the USS Monadnock, not the USS Monitor, though I think it is a reasonable approximation. Also please credit Starseeker for finding detailed drawings of the Monadnock turret engines in the National Archives, a crucial bit of research. I will send you an email to the address in your post above. Thank you for your interest. Best, MIchael

DrPR:
Hmm. Not quite sure what's going on, but I'm also seeing occasional glitches. So far, the jp2 originals all seem to be OK though. I'm playing around with options to produce a better PDF, but on the whole that's looking to be tricky and take a while...

Since the book itself is a product of the North Carolina state government and (according to the statement at archive.org) not subject to copyright as far as NC is concerned, it may be that the best way to go long term is to re-typeset a version of the book to put online that will consist of real text + images rather than scanned pages. At almost 600 pages that's a bit of a monumental task, but I have a feeling the images of the drawings themselves will be big enough without adding images-as-text to the equation... and the scholarship is certainly worth preserving in the most usable form we can manage.

I'll poke around with approaches to achieve a good output... there are two or three possibilties I can think of, all unfortunately rather labor intensive. In the meantime, at least we have the jpeg2000 images.

Francis:
Neat looking conference! In case the original source drawing of the Monadnock turret engine Michael mentioned is of interest, I've uploaded a downsized version here which hopefully will be clear enough and small enough for use in slides: http://bzflag.bz/~starseeker/National_A ... engine.png (Cliff Yapp = starseeker, bty.)

If you would like an illustration of the Monadnock to compare the Monitor with (the Monadnock appears to have been a bit more complex?) the line drawing here is the best I have for the purpose: http://bzflag.bz/~starseeker/National_A ... adnock.png

The same folder has larger versions of those images and the directory http://bzflag.bz/~starseeker/National_Archives/full/ has the full sized original scans, but watch out for those as they're pretty large and may run your computer out of memory trying to work with them.

Cliff

DrPR: How does this file behave for you?

http://bzflag.bz/~starseeker/monitor_part1.pdf

It's only the first 90-odd pages and it's a lot bigger, but I seem to get good scrolling behavior here. (File size should be about 90 Megs - if its not that big it's still uploading.)

Cliff,

I paged through it and didn't have any problems.

I have seen similar problems with some patent searches using Google Patents to look at PDFs. I contacted them and they said they were occasionally seeing this problem. When I opened the same patents using the US Patent office search engine I didn't see the problem - using the same Adobe PDF reader.

My guess is that some PDF generating program has a bug.

****

I have scanned several books (up to 800 pages) and other documents using OCR to put the text into Word, and scanned the images into Photoshop where they were saved as JPGs. Then I inserted the JPGs into the Word text and saved the file as a PDF. Actually, I use the CutePDF printer driver to direct printer output (from any program) into a PDF file.

It is a lot of work but the results look great and file sizes are a fraction of what they would be as scanned images. Here are links to some of these files if you want to see what the results look like:

http://www.okieboat.com/GMM.html
http://www.okieboat.com/Official%20ships%20history.html

It took about two months to scan and reassemble the GMM manuals, working 4 to 12 hours a day.

Phil

_________________
A collision at sea will ruin your entire day. Aristotle

Switched from Rhino3d 4.0 to Rhino 5.0 beta. The new software is 64 bit. It really helps make the larger files in this project more manageable.

Today I installed the engine and the gear train, so finally we have an overview of the turret elevating and drive machinery. This would be how it looked under construction, around Thanksgiving, 1861. The point of view is looking forward and up from a vantage point below the ship's galley area. I turned off the steel bulkhead for visibility. The longitudinal metal beam seen above the deck beams is the floor beam of the turret.The height of the engines within the gearbox is fixed by the position of the crankshaft throw. This is a position we can find on good, clear drawings. Here is a glimpse of the two connecting rods, now in place on the crankshaft. I treated the V-twin engine as a "group" and positioned the whole assembly, vertically, using the crank throw, at the left of this image.It was a pleasant surprise to find that the top of the frame of the portside cylinder fit precisely to the bottoms of the overhead deck beams. Bear in mind that we are fitting a USS Monadnock turret engine into the USS Monitor, on the assumption that the two engines are very similar. In fact, the Monadnock engine fit into place very well, perhaps exactly.From the McCord collection, it is clear that the bore and stroke of the Monitor's turret engines were 12" and 16", respectively. Yet in some 1997 CAD illustrations of the turret engine, we find cartoonish cylinders with tiny diameters. I got another clue today about why these artists drew such skinny cylinders. It turns out that if you view the whole assembly from the top, this is what you see:The hole in the engine frame in effect crops our view of the cylinders from above, so that they appear to be long and skinny. If you were working from a murky overhead view, it would be easy to assume the edges of the hole in the frame were the edges of the cylinders. In fact, seen whole from below, the cylinders are robust. They look like this:It was sort of amazing to see how everything fit together without physical interference. I was worried the valve gear, which is all over the place, might be snagged by a gear, but there are no such problems. The system needs bearings next, and framing. Two vertical stanchions flanked the crankcase on either side. Ericsson used them to support the weight amidships of the crankcase, gearbox and spur gear -- and he also used them to form the legs of the galley stove.

That is amazing work - especially that the pieces fit into place without interference. That's quite a testimate to your modeling skills and ability to interpret the original drawings - congratulations!

That quality of modeling makes me think of the "Virtual Apollo" and "Virtual LM" works Scott Sullivan put together some years back - at the rate you're going mcg, you'll be able to publish a "Virtual Monitor" book along the same lines!

Excellent Michael, that looks awesome! You've got to be happy with everything coming together so well, all that hard work is really paying off.

Dean