The Ship Model Forum

Thank you for this compliment Phil. Coming from you it means a lot to me. Michael

Monitor solid model: Dave Crop at the Mariners Museum suggested I contact you. I'm modeling the hull in Autocad and / or Rhino 4. I have hydrostatics and stability data worked up and ship motions in waves data as well that I can share.
Best Regards

Sean Kery Vice Chairman SNAME Marine Forensics Committee

Hello Sean,

Welcome to the forum!

I looked up the SNAME site and noticed your recent paper listed. Looks like truly fascinating work.

https://www.navalengineers.org/flagship ... 1-7-12.pdf

It will be great to learn more about it. Glad you found us! Do you have any screen shots you might post of your model?

best, Michael

Here is a photo of the USS Monitor's two side-by-side boilers. The photo has been flipped upside down because the wreck is upside-down. The shot was taken from from aft, looking forward. Following is the Rhino3D representation of the starboard boiler. This is a conventional marine boiler called a "Scotch" boiler, discussed in detail here.

http://en.wikipedia.org/wiki/Scotch_marine_boiler

The steam pipe is visible peeking out from behind the chimney. Steam presssure was just 40 psi.

The CAD sketch is based on drawings in Peterkin.

Michael

Great work, Michael. I'm glad to see you are back at work on the Monitor.

I won't ask if the house remodeling is done, because it seems it is a never ending project.

Phil

Thanks Phil. The renovation is finished, finally.

Here are two open views of the boiler installation, one from above the engine room and from below the galley. Each boiler was 8 feet wide and 9 feet tall, not counting the chimney. Only one wooden deck beam is shown, the one capping the central bulkhead. The rest are turned off for visibility. In the third image the deck beams are restored. The chimneys exhaust vertically to the deck between the last two aft deck beams shown. The fourth image shows the machinery in the context of a roughed-in hull. The side plates flanking the boilers are the walls of the coal bunkers. Michael

Michael,

Great work on this. Really well done. Do you have plans on doing the entire engine? I've been exchanging emails with Rich Carlstedt (builder of the Monitor working model engine) and he asked if you'd still been working on this. I know he's going to do a book on the Monitor's engine, and he may be in the market for someone to do a 3D CAD representation for him.

Keep up the awesome work!

-Devin

Awesome work Michael, it looks fantastic!

Have you had a chance to check out any of those free renderers for Rhino? I'm asking because if you ever get around to adding some textures to this, it would put it over the top, way over.

-Dean

Many thanks, Devin and Dean. Mainly I am still focused on the part of the ship that is still underwater, chiefly the galley and bulkhead areas. Tne new Rhino 5.0 has a minimal rendering capability built into it -- I will have to teach myself how to use it as a first step. Here is a view facing aft toward the boiler installation. The curved panels are the walls of the coal bunkers. The bunkers were filled from a series of manholes (scuttles) set into the armored deck.

There are two slightly raised catwalks running alongside the boilers from the galley back to the engine room. I think these catwalks have to be elevated to gain enough width to walk along comfortably. These catwalks are elevated about a foot above the galley's deck. In the conjectural drawing shown, the width of the walkway is about 32 inches, narrowing to 22 at the stanchions. Might have to sidle past those. Note that the boilers were lagged, that is, insulated with layers of wood and iron. Touching the side of the boiler was not hazardous.

Woo - hoo, more activity on the Monitor Model! Lookin good!

I can't quite tell - are those the new (well, old) style spur gear upgrades tucked away in there?

Nice idea Dean - given the quality of this model, feeding it (with some good textures) through a raytracer would produce images so good it would almost be eerie. Combining such images with better scans of the source drawings (not all of them obviously, just the ones with the best/useful information) would make a very compelling engineering handbook for the Monitor - Peterkin 2.0!

Gah - I just realized all of my old links to resources on bzflag are broken. In case newcomers to the thread want to scope them out, here are the corrected links:

Improved PDF of Peterkin book from archive.org:
http://brlcad.org/~starseeker/USS_Monit ... onitor.pdf

Monadock engine turret detailed drawing (scaled and full size):
http://brlcad.org/~starseeker/National_ ... engine.png
http://brlcad.org/~starseeker/National_ ... ngines.png

As long as I'm making sure links are current, here are the links to PDFs of the first two volumes of Project CHEESEBOX (apparently no one has made a PDF of volume 3, but I believe the first two volumes contain most of the period information):
http://handle.dtic.mil/100.2/ADA033069
http://handle.dtic.mil/100.2/ADA033070

Hello Cliff,

The Camanche style gear set was introduced here:

viewtopic.php?p=509143#p509143

Yes, the T-spoked gears are permanently installed now. The old gears are scrap. Now that we have boilers, the next steps are to connect steam lines to the turret engines, and to fill in the control and safety valves. Michael

Micheal

That's incredible work. It's really coming together. Can't wait to see the fully piped steam system.

Thank you Fritz. The piping is actually pretty interesting. Steam exhausted from main engines was cooled off and, for the most part, converted back to feedwater in the condenser. However, steam from the turret engines appears to have been exhausted directly to the air, through a small port in the deck near the stern. Michael

Here is a test fit of the two safety valves. The valves are mounted above the main steam lines out of the boilers. Each valve is intended to limit steam pressure in the boilers at 40 psi, maximum. The 6-inch blowoff pipe running between the two valves is to be connected to an exhaust line

The lead cubes weighting the valves are putting about 210 lbs of downforce on each lever. Each seated valve, assuming a 40 psi boiler pressure, produces an upward effort on the lever arm of 784 lbs. The length of the lever arm, measured from the fulcrum to the weight, is 15.86 inches. A 15.5 inch value is reported in Peterkin as the distance from the valve center to the weight, but re-calculation of the lever's properties suggests about 15.5 inches is actually the full length of the lever arm. This is a good thing because a longer lever would not easily fit in the tight available space. Here is one of the two valves seen from below: The position of the weight, straight aft of the valve, is conjectural, but it is the only way it can be made to fit in the available space without rotating it off-axis. Note that in an emergency, if you needed extra horsepower, you could probably tie down the safety valves with a loop of cable over the lever arm and under the steam output pipe. Here is the mechanism with the outer castings turned off:The part of the valve exposed to steam is 5 inches in diameter.
Seen from below the valve seat casting looks like this: The valve bodies and pipes are based on a beautiful formally drafted, fully dimensioned drawing in the Stevens collection. The weight and its hanger were done from formal drawings reproduced in Peterkin. The rocker arm and its linkage, however, are CADed from a doodle, hand drawn in pencil on the formal drawing of the valves. It is an ancient doodle, possibly done in a hurry by Ericsson or McCord. The centers and dimensions can be relied upon, but the style or 19th century "look" of this external mechanism is just a guess on my part. For examples of contemporary safety valves I used photos of English Great Western locomotives from the 1850s-60s.

The safety valves protrude up between the deck beams, and a concern was whether or not the weights would clear the forward face of the aft deck beam. It worked out okay, as shown here.

Immediately aft of the safety valve for each boiler is a main steam valve, in draft form in here: Michael

This main steam valve, one of two, was opened and closed from the engine room with a handwheel and jackscrew..

These many valves and pipes are secured with rings of nuts and bolts. By good luck, a new free plug-in for Rhino3D has recently been published that generates nuts and bolts of all common sizes. It is called BoltGen and it is wonderful, but the fully threaded bolts really seem to hog memory. Accordingly I have been using faux bolts like these.The nuts are made by the boolean treatment of a whole bolt and a nut. It results in the single closed surface shown here at left. Only a few threads show, so it seems more economical of memory to use this technique. The boltheads are also cut away from the bolts, and the centerpoint dot is used to position and array (in rings) the whole assembly. Michael

Michael,

Beautiful work! Following your posts has almost been like excavating the real Monitor and putting together the pieces.

Threads are a problem. If you have only one or two bolts the gain in file size, increase in renderting time, etc. are acceptable. If you have thousands of nuts, bolts and screws the file size becomes impractical.

Phil

Awesome! Great to see work continuing on this.

I agree - internal, normally invisible threads are going to be a major resource hog for something like this, and aren't strictly necessary. That's the kind of thing that might be better handled by assigning some kind of attribute flag to the surfaces that would be threaded in reality, then using a procedural tool to recreate them "on the fly" if some application like FEM stress/strain analysis needed the actual threads. For semi-transparent rendering situations a rendering shader is probably a viable option, if that ever comes up...

Crossing my fingers that someday you can publish a book about all of this - really impressive work!

CY

Thank you Phil and Cliff for your encouragement, and for amplifying on the high memory cost of all these threads. The jackscrews for opening the valves are in plain view, so they they have to be included, but for the bolts, I am only using a few visible threads. It adds up, though. For these two main steam and safety valve assemblies, I used 236 hex heads. This is an example of why it is difficult to go back to physical modeling. In CAD, we can do 20 of these hex heads at one click. Having completed one single valve assembly, we can do the whole of the second, mirror image assembly with one click. On the workbench...

The basic steam system for the turret engine is beginning to emerge. Before I drew this I had wrongly guessed that the fitting behind the big T-tube was a control valve for the turrret engines. It is just another juncture with a ring of bolts. This suggests there is probably a valve to start and stop the turret engines in the galley.

Here is a pictorial of the completed main steam and safety valve system and some of the piping. Top view shows how the valvework is notched between two deck beams and between the smokebox chimneys. Michael

Went back inside the main steam valve to complete the head mechanism. Looks like this: The shaft and the valve head are two distinct components, as indicated in this image by the slight gap between them. The rotating mushroom at the end of the shaft is captured by a cap: Normally I probably would not work out the interior of the valve, but I am going to use this one to create from scratch a similar valve mounted inside the galley. This new valve was used to open up the turret engines to live steam. There seems to be no documentation for this valve, so I will manufacture a conjectural model.