Washington Navy Yard cannons show extensive corrosion

[cannonmn]

The historic bronze cannons at the Washington Navy Yard show the most extensive bronze disease damage I've seen in a single collection. Most of the weapons are somewhere between moderately and severely impacted. Every weapon I checked at the Washington Navy Yard last week showed evidence of bronze disease. On many, the given names of the weapons are no longer legible; you have to read the sign or look up the names as they were recorded some years ago when they were still legible. All other marks on the diseased weapons are similarly degraded.

I made some calls and wound up with a name and phone number of the person responsible for that area, then left a voicemail since the phone was not answered. I'll follow up on that if there's no response after a reasonable time.

Here's a link to a slideshow of paired photos taken last week, one of a weapon overall, and the other of an area impacted by bronze disease. The numbers "No. __" in the titles of each pair of photos correspond to the Navy's description of these guns, cached from the Naval Historical Center's website.

Slideshow of damaged cannons:

http://tinyurl.com/5bypam

The link below goes to the cached webpage giving the Navy's descriptions of the guns in Leutze Park, Washington Navy Yard.

What should be done about this?

I'm sure smarter people will come up with something better some day, but if I were asked right now what could be done immediately, I'd say:

a. Get the weapons out of the sun and rain immediately.

b. Assess them to see which would benefit most from cleaning, stabilization, and application of microcrystalline wax.

c. Treat the cannons in priority order established in step b, as funding is available.

d. Re-assess ultimate display/storage location to optimize security/stability/public access/interpretation.


Navy's descriptions of guns in Leutze Park

http://64.233.169.104/search?q=cache:VL ... cd=1&gl=us

[R. C. Hubbard Jr]

cannonmn,
not wanting to sound stupid, but What is bronze Disease? Does it refer to the leaching of the coper ect?
Bob Hubard

[cannonmn]

Bronze disease has appearance of dull very light colored powdery surface, light green with valleys sometimes filled in with white s__t. It happens a lot as has been mentioned in areas with available carbon compounds in the air, and moisture is a catylist for it. It commonly afflicts ancient Roman coins, so most of what is known about it and its removal and prevention comes from coin collectors and dealers.

Another person told me that the CO2 and H2O react to form carbonic acid which settles out with dew or rain, called "acid rain." The acid rain of the east damages cannon, statues, and apparently lakes and forests. However, objects not exposed to dew or rain can also get b.d., it just is a slower process I guess.

It has been a while since I read up on it, but google "bronze disease" and there's a bunch of info.

The corrosion product is I think CuCo3 which rain washes it off onto the concrete foundations for the cannons and stains them green.

Smooth, shiny, dark patina: Good!

Dull, powdery, light green or turquoise surface: May be bronze disease!

Any bronze cannon that has a sandpaper-like surface almost certainly has or has had B.D.

All the bright-green bronze guns in the National Parks suffer from bronze disease if they have a dull, powdery-green surface. If they are shiny, they are probably stable for the time being, but will start to degrade over time. Any such shiny cannon should be waxed if it is going to be left outside. Cannons with bronze disease should be moved indoors until they can be stabilized and preserved. Cleaning the corrosion products off, stabilizing the surface, then applying hot microcrystalline wax is normally what is done with public statues etc. The m.c. wax gets down into pores and cracks better than other coatings, I'm told.

[Mike w/ 34th]

"Bronze disease" is also known as "chronic adrenal insufficiency".

Apparently, the new usage of the term was invented by some coin collector who's never heard of "verdegris".

[cannonmn]

never heard of "verdegris".

Thanks that's an intesting point. After I read that, I looked into Verdegris a little. The first 6 pages of google when I put in "verdegris" all either involved fake patination of metals, or a blue-green color with that name. A few entries talked about mythical goddess with the same name. There was nothing in those hundreds of hits about bronze disease. I grew up right after WWII, and often heard the term "verdegris" used for corrosion on brass such as Army belt buckles.

[cannonmn]

http://www.go2gbo.com/forums/index.php?topic=148160.0

[cannonmn]

I need to correct one thing I wrote above. The cannons I'm concerned about are being corroded by a combination of acid rain and direct sunlight. I've noticed that cannons that were painted or that were in the shade were in much better condition than those that were in direct sunlight. I incorrectly identified the problem as "bronze disease" but I'm a little smarter now.

[cannonmn]

5 August 2008
Rear Adm. Patrick J. Lorge
Commandant, Naval District Washington
1411 Parsons Ave SE, Suite 200,
Washington Navy Yard, D.C., 20374-5001

Dear Admiral,
Sir, I need to bring an important matter to your attention. I’m an amateur historian with a special interest in antique artillery pieces. Leutze Park near your quarters contains some of the rarest and most valuable trophy cannons in this country.

This summer I visited several major military museums in the US, and photographed the bronze artillery pieces on display. My tour included Fort Ticonderoga, NY, Watervliet Arsenal NY, Fort McNair, DC, the Washington Navy Yard, and the US Naval Academy. I’ve been studying these old cannons for the past 30 years and have a pretty good eye for the relative condition of the pieces I’m looking at. I have to tell you that the guns in Leutze Park seem to be in poorer average condition than those at any other place I visited. When I contacted the Naval Historical Center about this matter, they told me I should write to you.

When I got to the Navy Yard about two weeks ago, I was shocked at the decrepit condition of the bronze guns and howitzers in Leutze Park. Many of the guns have had their beautiful and informative engraved markings partially or largely removed by corrosion. When I first looked at them around 1980, to the best of my recollection almost all of the given names engraved on banners on the chases of the guns were completely legible. Now many are illegible if not completely erased by atmospheric corrosion. The engraved royal coats of arms have faded almost completely on some of the Spanish guns. If you need solid proof of what has happened and the timeframe in which it has occurred, perhaps the Naval Photographic Center has some older photographs you could use for comparison.

I recommend you have a professional bronze conservator assess the situation and make recommendations, then go from there. I’d make it a priority to stop the ongoing damage as soon as possible even if it involves moving all of the guns indoors until their condition and need for treatment can be assessed. If I can be of any assistance, please let me know. If you request funding to address the issue and don’t obtain it, I’ll see if I can get some private sector assistance for the project.

Very Respectfully,

John L. Morris

[RaiderANV]

Thinking that'll make a great section for the Washington Times. They'd run with it. Leaving them outdoors will destroy them but we think that's best until we can preverve them. They've only been waiting a few decades, what's a few more gonna matter. Then turn down funds to take care of the job. Yeah,,,,I'd send it all to the newspaper.

[cannonmn]

A few posts back I posted a letter the Navy sent me, which said they weren't going to do anything to get the detertiorating bronze cannons out of the weather, and some rationale.

I spent yesterday afternoon at the Washington Navy Yard and in the Navy Museum so I could check the facts they gave me.

Here are some of the points they made in their letter, and what I found:

They (the bronze cannons) do show the wear and tear of their past use and their age. Many date back to the 1600's. Some were damaged in battle. Some were retrieved from sunken ships.

What I found: One cannon dates back to the 1600's, a Spanish gun dated 1686. There are some undated howitzers but none of them look pre-1700 to me.

I found no evidence of any battle damage on any of the bronze cannons, and I looked each one over carefully.

I examined the detailed writeups about the cannons that appear on their website, and read all of the signs carefully. None of what I read mentioned any shipwreck recoveries. Perhaps they have additional information they aren't revealing about these guns, I don't know.

Placing them in the National Museum of the U.S. Navy would displace other parts of our Navy's history.

I looked all around the entire indoor museum. There's a very large open area near the front of the museum, a small portion of which would easily accommodate the guns. The large open area is sometimes used for receptions etc. so I'll leave that one alone since they do have a use for it.

At the rear of the museum is a large area where a bathyscape takes up a lot of room on the right side facing the rear of the museum. On the left side, there isn't much at this time, a few ship models, a few empty display cases, etc. There are two very large replica naval guns on carriages. I measured the area that was completely open in that part of the museum, and got 45 by 48 feet, or 2160 square feet. That would be much more than what would be required to store all of the cannons in the park. I guess the Navy would have to find some other place to store their empty display cases and replica cannons, so maybe that's their objection. Anyway, go figure. Here are some pictures of the spacious rear section of the museum.