I planned on using the area on Boca Chica Key known as the Submarine Pens in my next Early Adventure of Mac and Wood, but ran into the wreck of the Isaac Allerton that is going to be the main local. The Pens (whether they are or not is TBD) will be in the next Mac Travis Adventure.
The story is going to be based around the Lower Keys, specifically the area around Boca Chica, Sugarloaf, and Cudjoe Keys. I saw what has locally come to be referred to as the submarine pens while on a flight out of Key West and a subsequent kayak trip through the area.
Now, I've got to decide how to use them in the story. I could use your help here, if you have any ideas please leave a comment. Anything I use in the book will get you a free signed copy.
The layout is much like a neighborhood. Abandoned developments like this are not uncommon in South Florida and the Keys. There are several distinguishing factors that make this one different. I’ll list out the two sides of the conversation below.
In favor of Submarine Pens:
The canals and lagoon are much deeper than needed for a residential canal system. The one’s I’ve lived on, in Marathon and Big Pine, are between five and eight feet deep, plenty of draft for power boat or moderated sized sailboat. As we took the kayak to check out the Pens, I didn’t have a depth sounder, but I can tell the water Depth is well in excess of a residential canal. The water is extremely clear and I was unable to see bottom. This would lead me to believe that it is in excess of 20’ deep. I checked Navionics on line maps and there are several spot soundings of 17’. Dredging to that depth would be very expensive, and beyond the scope of what a residential developer would consider.
Digging lakes to provide fill for building projects is common in Florida. The resulting excavation site beceomes a scenic lake. If that were the case here, that would provide a reason to incur the expense. There is no evidence of fill being used here.
The lagoon is much larger—and deeper than needed. The expense to dredge the open water lagoon, would have been huge. Especially as it appears the soils have been moved off site. A thin strip of land remains. I read that it was formed with the fill, but from my firsthand observation it appears to be native material. My guess is that it is what remains of what was probably solid land at one time to protect the lagoon and canals.
The barrier island is barely wide enough for the paved road running through it. A residential developer would have no need to put a road there. If he had created the barrier from the excavation soils, it would have been built wide enough for homes. Facing West and open water, these would have been the most expensive properties in the development.
The bridge leading to open water has a twenty foot vertical clearance. That is too low for a sailboat, but much higher than many of the bridges connecting the Keys.
The geology is what is referred to as cap stone. a layer of limestone and coral below a thin layer of topsoil. The canals were cleanly cut, and in areas appear to have had concrete caps that run well below the surface. In residential canals with this type of geology, there is usually just a thin strip of concrete to create a seawall.
The entire island is owned by the Navy
In favor of residential development:
The canals are skinny and several are short.
The dredgec channel leading to the developement is skinny and does not maintain depth to the main channel. This could have occurred naturally over the years.
The area is very close to Cuba, which was the main reason much of this infrastructure was built. Submarine pens do not need to be this close to their area of operations, especially and island chain dependent on one road for supplies. There are many areas on both coasts that would have been closer to infrastructure, drydocks, etc.
The area appears similar in design to many other residential neighborhoods in the area (including mine).
There is no sign of any infrastructure, though there were several piles of concrete debris observed.
Submarine pens are generally bunkers to protect from overhead bombing attacks. There was no evidence of any kind of additional reinforcement to support such a structure.
I’ve got my theory, but I’m going to hold it close right now, so I can hear your ideas.