NEW YORK (Reuters) - A seagoing vessel plying the deep blue ocean waves might be the last place on the planet one would expect to find high-speed Internet.

But marine communications company Wheat International of Herndon, Virginia, is striving to deliver ship-to-shore Internet access to a market covering four-fifths of the surface of the globe, and one largely ignored by established network carriers.

Entrepreneur Forrest Wheat, the company's owner, aims to put the leisurely yachter, cruise ship passenger and sailors from merchant ships and fishing fleets on the Internet grid.

His year-old service, TeleSea, has tossed a line to U.S. coastal waterways, and eventually aims to encircle the globe.

"This service takes you places where Wi-Fi really hasn't gone before," said Brownlee Thomas, a telecommunications analyst with market forecaster Forrester Research, based in Montreal.

The vision -- impossible to achieve on land, where buildings and trees hamper Wi-Fi connections even 100 yards away -- is to deliver Internet links up to 30 miles offshore. This week, Wheat added satellite hook-ups for ocean liners.

Wheat, the self-titled company founded by the former MCI and Navy engineer, is rolling out an ambitious strategy to provide wireless hook-ups at short range in marinas, at longer distances off-shore and even in the middle of the ocean.

While short-range wireless computer connections are all the buzz as they pop up in a growing number of cafes, hotels, offices and airports, sea-going communications remain largely dependent on limited-range ship-to-shore radios or expensive marine satellite communications systems from British satellite company Inmarsat or Sea Tel, the marine communications systems manufacturer.

"TeleSea is more economic than your alternatives. And you can get the high-speed bandwidth," Thomas said.

Wheat does not sell the equipment but leases it as a service, gear included, in exchange for a yearly service contract. The service is by no means cheap, unless you plan to use the system for several years and amortize the cost over time.

Coastal Wi-Fi service reaching 30 miles offshore costs $500 a month. This service requires an upfront installation charge of $7,500, which includes one year's service fees. It is not meant for skiffs, but serious recreational or commercial boaters.

On land, the company has set up a network of radio antennas more than 200 feet high. These towers allow Wi-Fi signals to travel unobstructed for 30 miles or more, until the curvature of the Earth intervenes.

Wheat's coastal networks now operate off both U.S. coasts -- Cape Cod in New England; Long Island, New York; Chesapeake Bay and Florida, and Southern California, San Francisco, Puget Sound and Seattle, Washington, and Honolulu.

TeleSea offers unlimited Internet access for a flat, monthly fee at speeds up to 11 megabits a second, or 200 times faster than the Internet via basic dial-up phone connections.

TeleSea's near-shore Wi-Fi system relies on industry standard Wi-Fi equipment onboard the receiving end. The box weighs about 30 pounds and has a four-foot directional antenna that is fine-tuned to lower the atmospheric noise, which distorts radio signals, and extend Wi-Fi for miles.

Wheat is contracting with satellite service provider SES Americom SESF.LU to deliver deep-sea services from 22,500 miles above the Earth. The first satellite covers territory from the Caribbean to Hawaii in the Pacific. Additional satellites to be launched by SES will extend the reach of Wheat's services farther into the Atlantic Ocean, the Pacific, the Mediterranean Sea and other bodies of water.

Satellite signals are capable of offering Internet-based voice calling or video delivery services.

These signals can be subdivided on ocean-going vessels to allow crew to share access to available bandwidth, much like office workers share capacity on a department computer network.

The satellite service, designed for deep-water ships, carries even heftier up-front installation costs of $50,000. Monthly charges are $999 and up, varying according to data rates.

Wheat is wading into a market dominated by companies that use heavy fixed antennas and satellite dishes, systems that are cheaper to install but carry higher monthly charges. They are viable for large commercial craft but few pleasure boaters.

Sea Tel's Wave Call system offers monthly per-minute billing plans around North America in increments from $35 to $500, with additional fees for each minute over the allotted time. But downloading gigabytes of data quickly runs bills up into the thousands of dollars.