Growing At Sea

Two thirds of the Earth is covered by water.  As our population grows, so does our need for arable land to feed the people.  Meanwhile, development and urban sprawl consume more land each year.  A road 10 miles long by 25 feet wide takes 30 acres of land, and this would be a narrow road.  Taking away the deserts, the cities, the mountains that are too steep to plant crops, and places covered with ice, we've only got around 9 billion acres to feed 7 billion people.  Right now, around 40% of the Earth's land area is used for agriculture.  If our population is to continue to grow, it is essential we find more room.  There is room out there if we look to the oceans.  While the area costs nothing, the structures can be a bit pricey.  I'm not talking about kelp farming or fishing, I'm suggesting a floating platform-a garden ship.   

There are plenty of cities close to the ocean.  New York, Miami, Los Angeles, London, Tokyo, Singapore, Hong Kong...in the US alone, 125 million people live in cities which lie directly on the shore.  There's all that space just offshore, but the food for those people comes from hundreds and thousands of miles away. Seems to me it would make good sense to grow food right offshore.  The market is only a few miles away.  The area put into production is a function of investment, and as long as the product is selling and operating costs are kept down, the investment would be available.

There are some BIG ships out there.  Cargo ships, oil tankers, and cruise liners reach 1500 feet in length.  These are expensive, but we're not building an aircraft carrier.  For the most part, all we need is a floating platform able to carry the load and hold up to wind and weather.  Such a platform could be a free floating barge, moved around by tugboats and anchored in place.  It could be a structure secured to the ocean floor, as with an oil patform.  The technology is out there.  It simply needs to be adapted to the idea of growing crops.

There are some major advantages to this plan.  Being isolated, invasive weeds are a thing of the past.  Pest control becomes insignificant.  Cross-pollination several miles out to sea is barely a concern.  The environment is separate from the rest of the world.  There is plenty of fresh air and sunshine.  Wildlife will never jump the fence and eat the corn.  There would be no crime, although we'll need to take measures against high seas pirates.  

There are some major disadvantages which will need to be overcome.  Storms can wreck the place.  Collision avoidance must be taken into account.  The cost of construction and operation is significant.  Maintenance will be an ongoing issue.

Let's look at some considerations to do this.

FUNDING
The isolation offers a unique opportunity to finance the operation.  Those Manhatten condominiums sell for ungodly amounts of money, more than I ever heard of that's for sure.  Add a deck, put in some housing, I'm sure there are folks who would leap at the chance to live a few miles from a major city, but with no crime, no sirens, no city noises or hustle and bustle.  If the transport ferry makes a trip in the morning and another in the evening, supporting a community becomes a practical solution.  

There is the Freedom Ship which proposes to circumnavigate the globe.  It's funding source would be the 50,000 residents and thousands of hotel rooms.  Adding housing and hotels would give the project a viable means of financing the construction and operation.  In practice, the food grown would not need to be transported to shore if there are enough residents.  The Freedom Ship puts an airport on the top deck.  The proposed dimension of 4498 feet long by 738 feet wide offers over 70 acres.  One could grow an impressive volume of vegetables in such an area.  

With such amibitious projects as the Freedom Ship, a few questions arise:
-How big of a floating farm are we talking about?
-Is housing the direction to pursue?
-How much is this thing going to cost?
-How much food will it have to grow to be viable?

It is so easy to add one more facet to an idea like this.  Park the boat far enough offshore you can open a casino.  A few vegetables becomes insignificant when compared to the cashflow of a casino.  Before looking at the engineering and financing, the most important question is: Can vegetables be grown on a floating or ocean based platform?  Of course they can.  What's more, the advantages of the isolation and design make such an endeavor highly productive and efficient.  Financing the project is a matter of cost of operations and production per unit area.  As soon as the production and other income streams make the project viable this sort of thing would pop up all over the world.

ENERGY
We'll need energy.  Electricity would handle just about every need.  Lighting, pumping water, making fresh water, refrigeration, ventilation and environment control, and all the operations on board would be based on electricity.  Producing electricity at sea can be done with windmills and solar PV. 

WATER
The ocean has water all the way to the bottom.  It needs to be desalinated, and the energy supply is limited by the renewable systems on board.  This is a technical challenge, and not a difficult one to scale a desalination operation to the needs of the vessel.  To account for storms, some fresh water storage will be needed to carry the operation for a few days of clouds and calm winds.  Rather than process salt water, drawing water from a river above the estuary region would greatly reduce energy demand.  The natural flow of the river would also reduce pumping demand.  River water flowing to sea is fresh water that would otherwise be lost.  Near my home is the Suwannee River.  When the water is at extremely low levels the flow rate of hundreds of cubic feet per second is more than adequate for a very large ocean surface farm.

TRANSPORT
We grow it on board, but need to sell it on shore.  The product will need to be processed and packed for transport.  A shuttle will bring in supplies and take the product to the mainland.

DESIGN
start at the bottom, work our way up.
The bottom part of the platform would be fresh water storage.  Being low, it will serve as ballast to stabilize the structure.  Fill it up in the daytime while the sun is shining to provide power for the distillers.  Use it as needed.  We'd only need enough fresh water for perhaps a week.
The lower decks would store goods.  There will be plenty of supplies needed for operation.  Everything will need to be brought in on a transport.  At the same time, waste generated would need to be stored pending transport back to land.
There would be decks for housing.  All the people doing work would need a place to call home.  Efficiency of operations would demand common bathrooms and food service.  This is done in dormitories in every college on land.  
There would be space needed for handling, processing and storing the harvest.  A commercial kitchen setup does not take up a great deal of room for the volume it can serve.  I'd imagine the refrigeration room would be substantial.
There would be a laboratory to test for diseases, check the water and examine the soil.
A sickbay would be needed because even in a controlled environment, accidents can happen and people take ill.
A control room would be needed to monitor onboard systems.
Finally, there is the growing operation.

GROWING SPACE
The surface of the vessel as well as the south side of most decks would offer space for growing.  Vertical growing would maximize limited surface area.  The design of the growing area would be dependent on the location.  In the north, the sun comes in at a steep angle.  The growing area would be more vertical.  In the tropics, the sun is overhead.  The growing area would be horizontal.    

GROWING METHODS
The space is a premium.  For the investment, the project would need to plant and replant that space several times per season.  Crops that can be planted intensively, grow quickly, and bring a strong market price would be required.  Lettuce, potherbs, turnip, and mircrogreens fit the profile.  Crops that can be transplanted and are highly productive would be well suited here.  This brings summer squashes, tomatoes and peppers to bear.  Vertical crops and plants that can be trellised puts limited space to good use.  Pole beans, peas and cucumbers come into the selection. 

Soil and amendments would have to be brought in and blended to desired specifications.  If we are going to all the trouble, we can produce a rich mix designed specifically for the crops to be grown.  Since this will be an expensive undertaking, conservation of soil, water and nutrients will be aspects incorporated into the design.  Essentially we would end up with container gardening on a massive scale.  Drainage water can be collected and recylced along with nutrients that have leached out of the soil.  Soil testing requires a small lab. 

Seeds can be germinated below deck, grown to transplant size in a greenhouse, and planted intensively in the growing beds.  This maximizes production per unit area and shortens the time the plant spends in the growing beds.  Lettuce, for example, can be grown for 2 weeks in a greenhouse, taking little space per plant.  It can be transplanted in prepared beds with optimum spacing and finished in less than 2 months.  Cultivar selection, crop diversity, and staggered planting intervals can produce a steady crop.  Certified Organic is all the more practical as there are no neighboring fields which can generate overspray or contamination, plus the added price premium makes the investment in the enterprise recoverable sooner.

STORMS
A stout hull and a growing space enclosed with durable materials would hold up to rough storms..a greenhouse on a boat.   Protecting the growing space from winds and salt spray would be an important aspect of the design.  Getting above the waves would protect the vessel.  This suggests a platform secured to the sea floor, with the structure many feet above the water as being a practical solution.  

Breakwaters would serve to offer protection in open waters.  During the invasion of Normandy, ships were sunk off shore to protect the mulberry harbors being built.  Somehow it seems like poetic justice to sink an oil tanker to protect a garden platform operated with renewable energy. 

FIXED PLATFORM VS FREE FLOATING VESSEL
I envision the fixed platform design to be similar to building a bridge, possibly without connecting it to land.  Perhaps a long, wide pier.  Caisons and piers can be designed to take whatever mother nature can dish out.  The suspended surface area can be made to whatever size area is deemed viable.  A fixed platform connected to or near shore may make it possible to bring in utilities by undersea cables and pipes.  Grid power removes the need for renewable energy systems as well as the space and expense.  To offer a glimpse of the potential size, the Golden Gate Bridge is 8900 feet long and 90 feet wide, for a total area of over 18 acres.  Shallow water could allow construction of a vast area, with ecological concerns being the limiting factor.

A free floating vessel can be designed once and produced by assembly line for use anywhere in the world.  Several different components can be vreated.  One vessel to produce irrigation water.  One vessel for energy production.  One vessel for growing.  One vessel for housing and crew support.  Being close to town, a ferry could bring people to work each day.  That would remove considerable cost from design and construction, but I think it would be desirable to live out on the water.  Besides, if someone misses the boat in the morning the place is running shorthanded all day.  The largest ships in the world are approaching 10 acres in surface area.

Small organic farms growing intensively planted crops and SPIN enterprises offer the basis for planning of high production operations.  Duplicating that style of operation on a barge or a large pier should pose little trouble.  The engineering of an extreme barge can be replaced with a series of small barges.  A large pier can pose engineering challenges in certain areas prone to earthquakes, ice, tsunamis, and tropical cyclones.

LOCATION
Northern climates have the problem of a reduced growing season and brings winter ice which can do tremendous damage.  Since the construction costs are expected to be high, a warmer climate which allows year round growing makes the best sense.  The growing area can be enclosed, offering a suitable environment for plants throughout the year.  Enclosures have the effect of broadening the range of suitable locations. 

Movable vessels would have a limited envrionmental impact-just move the barge every few days.  A fixed platform will interact with tides and currents.  Crustacea, barnacles, and corals can call the place home.  Constant shade would be expected to impact the marine ecosystem.  As seen with sunken ships, the erection of undersea support piers and columns can create a new biome to support life.

The protected waters of Puget Sound is an interesting location.  A mild climate combined with ample rainfall, a sizeable population, and the community of experienced gardeners and growers on Vashon Island are practically ideal components.  Other protected waterways in the US include Cape Hatteras, Chesapeake Bay, and Long Island Sound.

Lake Okeechobee in Florida covers an area of 730 square miles.  The average depth is under 9 feet, with the deepest reaches extended to 12 feet.  It's fresh water and never freezes.  It has some protection from tropical storms with the distance to the ocean being at least 25 miles.  It would be a fine location for a prototype sea farm platform.  Recreational fishermen would take an interest in overnight stays on the platform.  I've worked in the area.  Hotel rooms are few and far between.

In Japan's Osaka Bay, the 2700 acre manmade island housing the Kobe Airport shows what determination and engineering can achieve. 

PROTOTYPE PIER
Imagine a pier extending into the shallow waters of Deleware Bay.  Perhaps it is all wood construction, inexpensive and proven durable in heavy seas which may be seen in the occasional tropical storm.  Perhaps the columns are reinforced concrete, built to last.  The initial pier, strong enough to drive on, goes out for a half mile, then broadens to an area 1 mile long by 1 mile wide.  Water and electricity is readily available, along with the bill for service.  There are 3 decks. 
The lower deck is parking, storage tanks for water and blackwater, cargo loading and unloading, and access to the marina.  The middle deck holds a lab, housing for staff, apartments, a restaurant, a bar, a processing center for the farm, some shops and tourist traps.  The top deck is completely covered with raised growing beds.  640 acres of them, with a capacity of over 64,000 standard sized beds,  with somewhere in the neighborhood of 13 million square feet of production area.  A vertical design could more than double that growing space.

ANCILLARY PROJECTS
I've already discussed the prospects of housing and the potential to generate investment revenue.  Establishing a permanent structure a few miles offshore presents a great deal of potential.

Mollusk, Fish, and Ocean Floor Farming
Mussels can be raised from suspended strings.  The determining factors for production are water flow and nutrient availability.  Fish can be raised in enclosures, or drop a hook.  If the location has good fishing, tourism becomes a practical pursuit.  Certain seaweeds, kelp for example, can be established, tended, and harvested to offer an array of commercial uses such as food ingredients and as a renewable feedstock for methane and ethanol production.

Tourism
This would be a unique situation.  Day trips, guided tours, overnight stays, fishing excursions, boat and jet ski rental, diving, whale watching, recreation, stargazing, and education all contribute to make the site an attraction. 

Navigation
The addition of a lighthouse or pair of lighthouses as well as navigational transmitters would be prudent in light of storm conditions.

Weather Station
Doppler radar, wind and temperature guages can be installed and operated remotely.

Energy
Solar, Wind, Tidal, Kelp harvesting, Algae harvesting, are all avenues to investigate.  While some energy would be used on site, it may be possible to transmit electrical energy to shore.  The feasability of biomass feedstocks is a function of production and transport.

 

All this is a thought experiment, of course.  I certainly don't have the means to make anything like this a reality.  Further development of the idea would be needed before a feasibility study would be practical.  Still, if we are to tackle the problems of a growing population and limited cropland, at some point we'll have to look at ideas like this and give them the further development needed.