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Topic review - USS Monitor turret drive machinery
Author Message
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Beautiful! Many thanks, Cliff!
Post Posted: Tue Nov 17, 2020 7:42 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Michael, about the Hamilton clock - I don't know if you're aware of it already, but there is a manual for it available here:

Manual for overhaul, repair and handling of Hamilton ship chronometer with parts catalog
Post Posted: Sat Nov 14, 2020 10:05 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Hello Rich,

Hooray and Congratulations! Here is the definitive and ultimate work on the USS Monitor engine, the new Gold Standard.

A few years ago someone in our community – Devin or perhaps Adam Winger – remarked to me that for this book, you had been sifting through the McCord collection of original USS Monitor drawings at the Stevens Institute archives in New Jersey. This is one of many key resources, but I realized then that this book would be a blockbuster, the ultimate reference.

Thank you for creating it, and thank you for your infinite patience in researching and CADing this book. Can’t wait to pore over it!

All best, Michael

For readers not yet familiar with Rich and his work, here are some links. The third one has more detail about Rich, and some photos of his shop as well. mcg.

USS Monitor engine model

Oct 17 presentation ... ine-model/

Post Posted: Sun Dec 08, 2019 12:40 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Very nice work!

Post Posted: Fri Dec 06, 2019 12:47 am
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Michael, I have finished drawing the entire engine of the USS Monitor.
A little over a month ago, I gave two Lectures at The Mariners Museum in Newport News VA and then donated 2 hard copies
of the book which is titled "Drawings of the U.S.S. Monitor's Engine " They also received a PDF Version.
I am working on getting them on the web - so stay tuned.
Had to go to school to learn CAD and it took 2 1/2 years to do this and is 309 pages
So here is the cover of the book and one of the internal drawings.
I do not intend to make any more hard cover books, and the PDF's are for 11 x 17 sheet size to show details I am still working on the "text" book which will describe the engine and it's functions and that will be a hard cover marketed by the Museum

Front Cover -Monitor- Copy.JPG
Front Cover -Monitor- Copy.JPG [ 131.71 KiB | Viewed 1838 times ]
Exploded View- Monitor.JPG
Exploded View- Monitor.JPG [ 151.73 KiB | Viewed 1838 times ]
Post Posted: Thu Dec 05, 2019 9:50 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Paged through this entire collection — excellent drawings of a 30 foot whaleboat, including a table of offsets and a sail plan. Might have application to other 1896 epoch ships as well. Nice to find good detail on a small boat. Also some good SIDE views of a Hotchkiss 6 pdr. Thank you Cliff.
Post Posted: Thu Aug 15, 2019 9:00 am
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Drawings going up for the Monitor USS Terror:* ... Sort%20asc

A few with turret details, such as but I don't see any of the turret engine.
Post Posted: Mon Jun 03, 2019 8:59 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Michael, Great work! PM sent...
Post Posted: Tue May 14, 2019 10:28 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Thank you Phil, this is a helpful precis on what to look for. The table of offsets would be an especially wonderful find. With the drawings I have I could probably make a model by hand sculpting it, but it would be pure guesswork without at least a central bulkhead. The USS Cinncinnati was a beautiful little ship but it had a "torpedo boat stern," one of those design features that is easier to render with sandpaper than with CAD. Michael
Post Posted: Tue May 07, 2019 1:40 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
The most likely collection of drawings to have the hull lines would be for the initial ship of the class. Any drawings for subsequent ships in the class would only include changes from the original design. For example, for the 27 ships of the Cleveland class and the subsequent missile conversions there are seven sets of drawings (about 12,000 individual drawings) in the Archives. However, only the drawings for the first ship, the USS Cleveland CL-55, have any drawings of the hull.

The Table of Offsets (if it exists) is much better than the hull lines drawings. The table gives the numeric dimensions of the hull that were actually used in the ways to build the hull. Often the basic Table of Offsets is included on one of the hull line drawings, but sometimes it is found in the "mold loft offsets" in papers included with the drawings.

If you are interested in the hull plating the Table of Sight Edges (in the mold loft offsets data) gives the numeric positions of the edges of the hull plating. This is far more accurate than trying to estimate the three dimensional curved edges of individual plates from flat two dimensional drawings.

I don't know when these tables started to be used, so they might not exist for ships built in the 1800s.

Post Posted: Wed Apr 17, 2019 2:11 am
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Thank you Cliff. I signed up for the Archive Catalog emailings.

In the USS Monitor library I found and purchased a small packet of drawings for the USS Cincinnati. As you know it was a fast cruiser from the epoch of the Spanish American war. Here is a link:

The drawings I received, however, did not include the ship's lines. Great idea to look for the lines of her sister ship. As for the marine chronometer, maybe there is an archive category for ships' instruments. Clearly I will have to visit the archives and learn more about how they are organized. Thanks again for your help, Cliff. Michael
Post Posted: Tue Apr 16, 2019 9:36 am
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
That sounds like it's probably this one:

Looks like only 2 drawings from that group are online, neither of which pertain directly to the ship itself. That may mean that there either aren't many in that group, or just that the majority of the drawings weren't "low hanging fruit" for scanning purposes. The other likely source for potentially useful drawings would be the other ship from that class, the USS Raleigh ( but it doesn't look like any of those are online yet.

The Hamilton drawings might be in there somewhere, but that's a small enough detail that the warehouse scene from Indiana Jones is probably not a bad mental image - they'd most likely be in some sort of contracting records, or part of a ship's drawing set, or...

One thing that might be worth trying (and also asking about the possibility of email notifications of new search results) would be to inquire at the NARA's History Hub website: - the NARA archivists are active in the forum, and I've gotten a number of very helpful responses.
Post Posted: Tue Apr 02, 2019 9:17 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Thanks for the information about the archives, Cliff. I have been intrigued by a cruiser from the late 19th century, the USS Cincinnati. Since they are by now well past “C”, maybe there are fresh scans.

Re this USS Monitor project, and to coin a phrase, it ain’t over ‘til the fat lady sings....!

There is another set of drawings I would like to hunt down. In 1941, Hamilton (the watch company) received a Navy contract to manufacture marine chronometers for US warships. Their chronometer was designated the Hamilton Model 21. There are usually one or two on ebay — they are highly prized and vastly expensive. Here is one: ... Swrblb~t9u

They had a special escapement mechanism that was uncanny in its accuracy. It would be fun to see the drawings and try to figure out why it was so good. And to do a 3d CAD version, of course, starting with access to dimensioned drawings. Michael
Post Posted: Tue Apr 02, 2019 9:01 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
No arrangement - I usually just periodically search the NARA ARC using their advanced search ( for engineering drawings in RG 19 with no keywords, and (so far at least) the default ordering of the search results if you don't give it a keyword seems to be the most recently added/updated entries in the catalog.

My understanding is the NARA staff are gradually working their way through scanning the ship drawings (so far, the ones stored flat since they're easier to deal with.) I've noticed a roughly alphabetical progression of new drawings over the months, but it looks like this grouping is the first one they hit that was from a monitor ship.

Any new work on the Monitor CAD model, or has it pretty much reached its finished state?

Post Posted: Mon Apr 01, 2019 7:55 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Hello Cliff,
These are really interesting. The date I noticed was 1896.

Do you have (or does there exist) an arrangement with the archives that alerts you by email when a keyword like “monitor” is associated with a fresh scan or update?

Post Posted: Fri Mar 22, 2019 5:43 am
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
I noticed that the NARA has posted a number of scans for the USS Puritan, which was a Monitor class ship:

Rather later vintage than the original Monitor of course, but perhaps some of the details will still be informative.
Post Posted: Sun Mar 03, 2019 4:42 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Thank you Michael for the info !
I looked at Scientific American in 1861 and 62, but not 1863, so I have to do that
I haven't dropped Devin a note yet.
Life has been extremely complicated since my post last month and delayed my response, but this is not the place for that.
Sorry if I mislead you on the condenser, there was only one, but the exhaust manifold had TWO pipes, which meant they had to have a "Y " pipe feeding the condenser.
I need to visit the National Archives in Washington DC to follow up on the drawings if available.
I am working with the Mariners Museum on publishing a book about the Monitor's Engine. Taking a Solidworks Class to help me in that venture !

Erickson built monitors for Russia and Sweden..and a South American country (??)
The Swedish monitor called the SOLVE'

It was smaller than the USS Monitor and only carried a single gun
I am Swedish and had a relative check it out for me as I do not read/write Swedish and the Swedish Marine museum did not understand my requests.
My cousin told me they gutted the original engine and used the ship as a barge before it was placed in the museum.
They also have no drawings or details of the original installation, even though John Ericsson is a real hero over there.

Post Posted: Mon Oct 16, 2017 5:10 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Hello Rich, welcome to the forum. That's interesting about the dual condensers, I had not known that.

Here are some Passaic type links pulled together from past posts and other collections.
This is the cover of Ian Marshall's book of watercolors, Ironclads and Paddlers. There is an excellent narrative journal written by a sailor on the USS Nahant, here: ... 0872497615

In the Scientific American for December 12, 1863, on page 372, there is a long article entitled "The Monitors". This volume of the Scientific American (V9) can be downloaded as a pdf from Google Books. The article is dense with specifications and dimensions for the original USS Monitor and for the nine Passaic class monitors that followed it.

I was surprised to learn that the Czar built ten Passaic class monitors for the Russian navy, beginning in 1865, following the American plans. Presumeably this was under a licensing agreement from Ericsson.

Re the turret drive, I agree the V-twin engine was essentially the same as that of the original monitor. The drive configuration was quite different because, as you point out, the turrret axis was like a tree supporting the pilothouse, and the turret had to rotate around this fixed tree.

A diagram is posted here:


And here is a photo of the same general type of system aboard the Camanche:


The reversing engine drives a crown gear that rotates in the plane of the lower deck, and is a little hard to see in this photo. It is geared to the vertical shaft at right, which ascends through the ceiling to drive the turret via a large diameter gear mounted below turret floor.

Finally, here is a link to Devin's expert model of the USS Weehawken:

best, Michael
Post Posted: Sun Sep 17, 2017 4:27 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
Cliff and Michael
I just joined your Forum, but thought I would poke in on this .
Yes, the Passaic was the next Monitor built after the famous battle on March 9, 1862
It was the same-yet different. The hull design was changed( rounded) and was bigger and most notably, the Captain and Helm were moved to the top of the turret .
You might say that it was the first Super Structure & Bridge ship
The engine was close to the Monitor's design, except for the Exhaust/Condenser piping ( 2 instead of 1 )which required a different porting on the engine.
The Monitor had an Asymmetrical Engine and the Passaic had a Symmetrical Engine design.
It took well over 7 months (as I recall) for the Passic to be built, far more time than the Monitor's 100 days
The Passaic first met up with the Monitor in Washington Navel yard on Christmas day 1862 and of course, the Monitor was lost a week later on Dec 31 when it went on a mission.

I suspect the turret drive was the same.
I can't get the link to display your Passaic Battery Drawing, but suspect it is the one in the National Archives file with a 3-3-32 number on it.

It has been fabulous to follow the comments and drawings here...thanks fellows !
Post Posted: Wed Sep 13, 2017 10:25 pm
  Post subject:  Re: USS Monitor turret drive machinery  Reply with quote
My pleasure :-).

I've had a chance to check out a few more drawings at the NARA and stumbled across this drawing from the Passaic class ships (which appear to be the design that immediately followed the Monitor):

It's undated unfortunately, and it documents the "Battery Engine" rather than mentioning the turret, but the style of the text and look of the drawing make me wonder if it might date to the civil war period.

Also, if Wikipedia has it right ( ) the civil war ironclad Passaic was in service in one form or another until late 1898. That may indicate that the following drawing also pertains to the same ship, although it's not immediately clear what alterations were made over the years that would be reflected in the drawing:

There may or may not be any useful info in these, but I thought I'd mention them in case :-).

Post Posted: Fri Feb 03, 2017 9:22 pm

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