Scientists have long seen great potential in farming the oceans for food. Architect Wolf H. Hilbertz of the University of Texas at Austin is keen on another possibility: "growing" buildings in seawater.
Mr. Hilbertz has developed and demonstrated a process for growing structures with the strength and durability of concrete in a marine environment.
Indeed, the ocean does most of the work. Mr. Hilbertz establishes a mild electric current underwater so that the minerals suspended in seawater are attracted and deposited on a wire mesh. The minerals accrete on the wire, which can be shaped in various forms, and over a period of six to eight weeks become a solid mass with the look and strength of rough concrete.
The electric field is established by connecting the wire mesh to the negative terminal of a battery and connecting another separate conductant to the positive terminal. The current passes from one terminal to the other through the ocean water. The amount of electricity required is so small that skin divers cannot feel the charge and fish are not harmed, according to Mr. Hilbertz. "The concept is so simple that it is almost embarrasing," says the bearded German immigrant who has experienced with underwater "electrodeposition" for six years and now has a patent pending on the process.
Simple or no, it has a wide array of potential applications. Underwater accretion could prove an inexpensive way to protect and reinforce underwater pilings at port facilities, and even mend cracks in steel-reinforced concrete. It could be used to build breakwaters and ship mooring facilities.
Mr. Hilbertz also envisions growing building components underwater for on-land construction, as well as creating some fully formed structures with simple designs -- like a quonset hut, for example.
"I'm excited about the process because it is not detrimental. It draws minerals out of the water that are being replenished every minute. It is a 'soft' technology," Mr. Hilbertz said in a recent interview in his Austin office.
Others are beginning to share his excitement.When Mr. Hilbertz began experimenting with seawater accretion six years ago, he says, most of his academic peers were skeptical. Fellow architects wondered why he was experimenting with building in a marine environment, and marine biologists said he should stick with architecture, he recalls.
Now, he has solid financial backing from some private Texas investors for his Marine Resources Company and a steady flow of mail each day from attorneys, scientists, and businessmen all interested in helping him develop and commercialize the process.
Earlier this month the company signed its first commercial contract with a California firm that will use the accretion process to protect pilings from corrosion at the Port Hueneme naval base in California. The California firm is doing the work under contract with the US Navy.
Mr. Hilbertz will soon fly to the Cayman Islands to continue negotiations with the government on a plan to build an underwater park. He proposes using his electrodeposition process to develop an underwater playground for scuba diving -- a popular sport on the islands.
General Electric Corporation has queried Marine Resources about the possibility of using the process to build an underwater pipeline for a coastal power-generating facility in Puerto Rico, Mr. Hilbertz says.
Marine resources already has built some experimental underwater structures to test the process and see how strong and stable the material is over time.
Artificial reefs have been constructed in St. Croix, Virgin Islands, and in Corpus Christi and Port Aransas, Texas.
In all case, Mr. Hilbertz says, follow-up studies have shown that the structures enhance sea life in the area. The artificial reefs become protein-rich sources of food and attract fish.
The material hs held up as well as concrete, according to Mr. Hilbertz, and he says more will be known about its engineering properties from studies now being conducted separately at the State University of New York at Stonybrook.