Since I have been near caisson lighthouses lately and found out last night that there is one in Maine, as well as the ones I saw in Virginia and Maryland, I wondered what other states also have caisson lighthouses?
Derith

Michigan - Rock of Ages
Maine - Lubec Channel
Massachusetts - Butler Flats & Cleveland Ledge

Looking to confirm my memory of Lubec, I discovered the Mass & Mich lights considered to be caisson style.

Dave

Connecticut - Conamicut (Sp?)
New York or New Jersey - Romer Shoals
Maryland - Sandy Point, Baltimore

[This message has been edited by JChidester (edited 07-26-2001).]

Deleware-- Fourteen Foot Bank, Harbor of Refuge

New Jersey--Miah Maull, Ship John Shoal

New York (Long Island) - Orient Point

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Diane

New York - Tarrytown


shirin

Some of the lights mentioned aboved LOOK like caisson lights but are actually pier lights - they are built on top of a pier or breakwater, and do not employ the caisson method of construction.

FWIW,

Dave

Would you post the ones that have already been written that are really caissons?
Derith

Spring Point Ledge ME was built as a caisson light, then rip-rap was added from shore to the light.

Here are some links to pages that describe various LH construction types. The caisson is a very unique method, also used for building bridges. You have to scroll about 3/4 of the way down the CG site to get to caisson. In the NPS site they include a list of caisson lights. Interesting that they include the Harbor of Refuge light as it is built on a breakwater.

Coast Guard Historian

NPS Caisson Page

NPS LH Construction Types

Dave

New York - Cold Spring Harbor
(original location)
Recent photos & coast guard photo with lighthouse on caisson @ http://www.scroope.net/longislandlighthouses/coldspringharbor.htm



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KRISTIN ERIN SCROOPE
kristin@scroope.net
http://www.scroope.net/lighthouses/lhlist.htm

New York - Race Rock
Recent photos & coast guard photo with lighthouse on caisson @ http://www.scroope.net/longislandlighthouses/racerock.htm

Seems there is a publication called "1994 Inventory of Historic LightStations". It has a list of all the caisson lights...anybody have a copy? Seems that some of these that you think are not caissons, really are. Of course, it is out of print and hard to locate one....anyone have an extra one? It would be a great tool to have..interesting info located in the covers.

Derith

The Inventory is out of print and out of date. I've heard from several that there were a number of errors in it.

Candace Clifford who helped put that book out told me that she has been keeping the web site version up to date:

Inventory of Historic Light Stations

http://www.cr.nps.gov/maritime/constype/caisson.htm This page is about Caisson Lights



[This message has been edited by JChidester (edited 07-27-2001).]

[This message has been edited by JChidester (edited 07-27-2001).]

[This message has been edited by JChidester (edited 07-27-2001).]

Read the description of a caisson light - the cylinder goes from the surface of the sea to the floor of the ocean. If a light is built on top of a breakwater it is not likely that there is a cylinder going thru the breakwater to the floor of the ocean/ sea/ bay/ whatever.

John's second link is the same as my second link. The NPS site, as well as the CG site, provide pretty good descriptions of the various construction types used in building lighthouses.

Candace Clifford's listing of lighthouses is an excellent resource, one that I have often used when trying to find information on various lights.

Dave

Here's a definitition I found for "Caisson" http://www.encyclopedia.com/articles/02135.html

Although the above-mentioned definition, sites the traditional method of sinking the rings into a bottom substrate in the water, I also have to disagree with the definintion.

I sometimes use concrete reinforced "caisson" rings in my work just as a support structure for excavation necessary within the confines of the rings. This excavation causes the rings to sink (similarly as they would in the water) into the bottom sediments (where on Long Island you may never hit bedrock though - it's all sandy sediments). So, "caisson" has become a common industry term for the ring itself, rather than the method.

Anyway, my point would be that a "caisson" structure can be utilized outside of its traditional use of being a foundaton sunk into the bottom sediments in the water...It's purpose being the strength of the structure and for stabilization in an otherwise not so stable environment. The rings themselves are called "caissons," more often than the method. So the foundation, can be a "caisson" foundation just being made of a "caisson", regardless of whether the ring foundation is sunk into a substrate above or below the water surface. So, the lighthouses that are on breakwaters or rocks that are also said to be "caisson" lighthouses, very well may be if the foundation is made out of a "caisson" ring.

[This message has been edited by kscroope (edited 07-29-2001).]

More on "Caissons"...

Historic Lighthouse Preservation: History of the Lighthouse Service & Lighthouse Construction
https://osiris.cso.uiuc.edu/denix/Public/ES-Programs/Conservation/Legacy/Lighthous e/lh3.html


[This message has been edited by kscroope (edited 07-29-2001).]

New York - Long Beach Bar "Bug Light" http://scroope.net/longislandlighthouses/longbeachbar.htm

Thanks a bunch, Kristin.....

IMHO, you can not go back in time 75 to 100 years or more and change how the word caisson is defined. Either the light was built using the caisson method in use at the time of construction or it was not. A pier or breakwater light is normally built on top of the pier or breakwater, not through it to the bottom. The Spring Ledge, ME light might seem to be an exception, but the breakwater was built out to it some time after the light was constructed using the caisson method. The Harbor of Refuge light is built on top of a breakwater. The breakwater was there first.

The way the term is used today may be appropriate for today's construction industry, but does not reflect the methods of the time period of construction of these lights.

FWIW, the use of the term "caisson" in relation to construction technology appears to be a rip off of the original use of the term. Before it was a consruction type, a caisson was used by the army to pull cannons. Today, they are used ceremonially to honor the fallen.

Dave

Here are some pictures that I took of four of the "caisson" style lighthouses in question. It is obvious that Orient Point and Spring Point Ledge are caisson-style, but one would question Latimer Reef and Saybrook Breakwater due to the fact they don't have the curve at the top of the caisson (which was meant to keep waves from crashing over the top of the caisson).

[img]http://albums.photopoint.com/j/View?u=968985&a=13472634&p=52348449&Sequence=0&res=high[/img]
Latimer Reef, CT

[img]http://albums.photopoint.com/j/View?u=968985&a=13472634&p=52348450&Sequence=0&res=high[/img]
Orient Point, NY

[img]http://albums.photopoint.com/j/View?u=968985&a=13472634&p=52348452&Sequence=0&res=high[/img]
Saybrook Breakwater, CT

[img]http://albums.photopoint.com/j/View?u=968985&a=13472634&p=52348453&Sequence=0&res=high[/img]
Spring Point Ledge, ME

All are built on Caissons.

"Keeping The Flame Alive in New England"
Ron


[This message has been edited by RFoster (edited 07-30-2001).]

For the sake of continued discussion, here is the definition of caisson style construction from the NPS page:



Spring Point is a caisson, as noted before. The breakwater was built out to it long after it was originally built. I would buy Orient Point and Latimer Reef as being caissons. I doubt you would find a nice pile of rocks in the correct vicinity to build your light. Probably there to help deflect breaking ice as it passed by.

Saybrook is a breakwater light. From the New England Lighthouses: A Virtual Guide website (http://www.lighthouse.cc/saybrookbreakwater/history.html)



Seeing as how the light was built on top of the breakwater some 10 - 15 years after the breakwater was constructed, I have serious doubts that the builders dug down thru the breakwater to reach the ocean floor.

All too often the descriptions given on web sites and in books is really not enough to determine if in fact a light is a true caisson light, or is really a cast iron spark plug type light placed on top of another (or existing) foundation. I would think the definitive answer on what lies underwater beneath these lights will have to come from a USCG source or the current society/group in possession of the light. That source will need either the detailed blueprints or first hand, look inside the lighthouse itself knowledge to give the real answer.

IMHO,

Dave

[This message has been edited by Dave H (edited 07-30-2001).]

Dave, Apparently, you misunderstood me. I wasn't trying to go back and redefine anything already defined 75 to 100 years ago.
Also, I looked at the sites you referenced, and I don't think saw anything that resembled what I know a "caisson" ring to be. So, I'm not so sure where you are saying the term got ripped off from.
The ring type used for the foundation of any lighthouses I have ever seen (in pictures or in person)that are supposed to be caisson lighthouses is exactly what I am familiar with as far what I know a caisson ring to be. I believe the rings we use in my work are exactly the rings that are used for "caisson" foundations for lighthouses....whether they be made of concrete or any other material. I remember seeing Orient Point lighthouse up close just a year or so ago, before I knew anything about lighthouse construction types, and saying that it looked like the foundation was a "caisson"...and then someone said it was. I was familiar with the word from work, not from lighthouse knowledge...and they strangely (or not so strangely) coincided...and that is all I am saying.
I don't think anyone here has decided on their own by looking at a picture of a lighthouse that it is or isn't a caisson lighthouse. They named the lighthouse because that's how they themselves knew it to be. Someone else - someone who knows about lighthouse construction - stated or published the fact that the lighthouse was just that...and to me, I can't see why they aren't caisson lighthouses. The ring was sunk into the substrate to provide a stable foundation in any case, be it above or below the water...the point is, in what I have read, to sink the ring into a bedrock type structure for stability...when they couldn't find bedrock, the rings many times were lost because they kept sinking into the sediments. In the case of the lighthouses you are disputing, the rock in those cases is the bottom. Why should you have to go further than that? It isn't like the rock floats above water...and I never read any specifications on how deep to go...just that they were seeking a solid substrate.
So, why can't you then have a caisson type lighthouse on rock above water? It doesn't seem the least bit possible to me that a ring was just simply placed on top of a rock and left at that - the rock surface had to be adjusted to fit the ring - the ring had to be sunk into the rock so that it wouldn't just slide off, shift or settle, just as you would do beneath the water.

[This message has been edited by kscroope (edited 08-04-2001).]

If you follow the link in my earlier post, you will see what the term caisson was used to describe some time before it was used in construction technology.

The CG and the NPS both desribe caisson style consstruction was going to the floor of the ocean. It may well be that there are cases where a caisson ring was used to help create a surface to build on, but if the caisson does not extend to the floor of the ocean it would not fit the definition used by the CG & the NPS. The use of a caisson ring does not mean that the light was built in the caisson style.

Dave

[This message has been edited by Dave H (edited 07-31-2001).]

In the quote you posted, I don't see any mention of the "ocean floor" as you refer to, just the "bottom"...and that's what I'm talking about. What is the bottom? You could go down into the ocean floor until you hit the other side of the earth and still not hit "the bottom". Also, note that your quote also says the "substrate within the caisson" and "the caisson was allowed to move further". I believe that is referring to the structure, not the method which is contradictory to your argument and supports mine. So, the "today terminology" of referring to the ring as a "caisson" is the yesterday terminology as well.

quote:
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The caisson lighthouse type used a large cast-iron cylinder, which was sunk on the bottom and filled with rock and concrete to form a foundation. Where bottoms were harder, contained rocks, and/or needed greater depth of penetration into the substrate, the pneumatic process was used for 11 light stations. The substrate within the caisson was removed and the caisson allowed to sink further into the bottom.
--------------------------------------------------------------------------------

Kristin,

If you take the time to read the pages that were linked to, it will become somewhat more obvious that the caisson went to the floor of the ocean. From the CG site:


The use of the "sunk" when used around water normally implies that something has been sunk underwater. To go thru a pier or breakwater made of stone and/or concrete would be quite a sinking.

You choose to use an interpretation that is convenient and ties in with what you know in the field of construction. I choose to use what would be the historical definition, as it would apply to the lights at the time they were originally constructed.

We will simply have to agree to disagree.

[This message has been edited by Dave H (edited 07-31-2001).]

Hog Island Shoal & Conimicut Shoal lights in Rhode Island:

Hog Island Shoal Light

Conimicut Shoal Light

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Rod Watson
[This message has been edited by Rod Watson (edited 07-31-2001).]

The following are for certain.....
(if there is an asterik, I saw them on my summer trip) The others are must sees...so many lights, so little time.
Wolf Trap, Virginia *
Newport News Middle Ground, Virginia
Solomon's Lump, Virginia
Sharps Island, Maryland *
Sandy Point Shoal, Maryland *
Hooper Island, Maryland *
Baltimore Harbor, Maryland *
Bloody Point Bar, Maryland *
Thimble Shoals, Virginia
Smith Point,Virginia
Point No Point, Maryland

Derith

I have continued to research the "caisson" topic, and keep finding reference to both the "caisson method" and the "caisson" as a structure (even within descriptions of the method).

The following definition, really says it all...
"caisson: in engineering, boxlike structure used in construction work underwater or as a foundation. It is usually rectangular or circular in plan and may be tens of metres in diameter." http://208.154.71.60/bcom/eb/article/3/0,5716,18863+1+18575,00.html

This definition refers to the structure and then states its uses as both for underwater construction and as a foundation.
In my opinion, I would find it hard to believe that this type of structure was devised specifically for the method of building a lighthouse out in the water. Caisson structures have been used in all different types of construction, and I have found no evidence to suggest that referring to the hollow cylinder structure or box used for the caisson method (or other foundation purposes) as a caisson is a new industry term. The name of the method does not refer the name of inventor of the method, which is very often the case. http://www.comptons.com/encyclopedia/ARTICLES/0025/00321792_A.html

So, I am still unsettled on the topic. It's kind of like asking, "which came first, the chicken or the egg?"
Perhaps the real problem lies in calling a lighthouse simply a "caisson lighthouse"...because there are obviously lighthouses that have been built by the caisson method which utilizes caissons...and then there are lighthouses that sit on caisson foundations that have not been sunk to the ocean floor. It seems a common enough problem that if people see a "caisson" as part of the foundation, they refer to the lighthouse as a "caisson lighthouse", a phrase that really doesn't make any differentiation between the method or the structure. I do agree that if you specifically are referring to the method of construction that the "caisson method" of building a lighthouse is as Dave has described. However, in my opinion, referring to any lighthouse utilizing a caisson as part of its foundation as simply a "caisson lighthouse" cannot be incorrect because the term is too vague.
If I find anything else, I will keep you posted.

Another caisson definition http://encarta.msn.com/index/conciseindex/19/0194A000.htm