Verizon, Sprint and Alltel have comparable technologies, meaning the difference between these three providers may be customer service. Sprint has a "D" rating, while Verizon and Alltel are rated better.

Making a choice often comes down to looking at costs–most providers offer discounts if you also buy phone service–and finding out which provider works well in your local waters. Talk to people in your marina before you buy.

LAND-BASED OPTIONS

Good old fashioned dial up connections, though long ago eclipsed by faster broadband options, still exist. Dial up connects your computer's modem to a telephone line, which enables you to dial into your Internet Service Provider (ISP). It is cheap–sometimes free–and relatively simple, making it an option for those who stay in port (you need a phone line) and use the Internet only on occasion.

But dial up is notoriously slow, even for routine tasks such as sending photos or downloading information, and most people now use it only as a backup for faster systems.

One such option is Digital Subscriber Line (DSL) technology, which relies on a high-speed, broadband network connection between your computer and a telephone lines. It transmits data much more rapidly than dial-up and does not tie up telephone lines. The DSL connection is always available and you can use the Internet and the telephone at the same time.

Your DSL modem, which is usually supplied by the ISP, connects to a modem at the provider's location, allowing data transfer over the phone lines. But the technology only works over a limited physical distance, and some areas have no service at all. Prices vary, but you can expect an installation fee of up to $150 and a monthly fee of $45 to $65.

Cable companies also provide broadband Internet service. The connection takes place through a cable modem, which uses cable television lines to obtain access. Using television channel space, data is transmitted over the lines, with different channels used for downloading and uploading.

Access to the Web is fast because the coaxial cable provides greater bandwidth than telephone lines, beating DSL speed by about two to one. However, that's not the whole story. Cable service is dependent on a shared bandwidth. You are sharing the space with other subscribers, which results in fluctuations in connection speed.

Some cable Internet providers charge a premium if you do not bundle the service with a cable television subscription. If you want cable television, you may be able to find an attractive bundled package. If you only want Internet access, you may look into companies that purchase access from cable companies and sell it at lower rates. Installation costs are somewhat cheaper than for DSL, running between $50 and $100. Monthly Internet subscription fees typically are $40 to $50.

SATELLITE SERVICE

Satellite Internet service is available worldwide, but it's the most expensive service to obtain, both in terms of equipment costs and monthly fees. It has less network bandwidth than either DSL or cable and slower transmission speeds, but it may the best–perhaps the only–choice if you are going offshore.

SEA TELMarine satellite systems require stabilization, which increases the cost.With two-way satellite Internet service, data is sent back and forth from your boat to a land-based hub, using an Earth-orbiting telecommunications satellite as the conduit. Most satellite equipment consists of a small dish, two modems–one for upload and one for download–and coaxial cables between the dish and the modem. Marine setups differ in that they need a stabilized antenna and a radome, which increases the cost.

Boats create unique reception issues. Being on the water itself doesn't impact satellite coverage quality, but the motion of the boat can affect the antenna's alignment. That's where the pricey stabilized platform comes in.

If something obstructs the "view" between the antenna and the orbiting satellites, service can be affected. The satellites remain in orbit over the Earth's equator. If you head north, an intervening mountain range, or even the earth's curvature, can affect communications. Still, these are minor irritations in a system that's largely reliable for offshore boating.

That said, be prepared to take a hit. The price for a stabilized antenna and radome varies tremendously, ranging from about $3,000 for a limited-capability unit to more than $100,000. Then there are the service fees, which start at $150, and hefty per-minute data transmission charges.

In the end, the service you choose will largely depend on how you use the boat, how you use the Internet and how much you want to spend.

If you live aboard and your boat is docked much of the time, economical land-based options may work well. Coastal and short-distance cruisers can take advantage of mobile systems like Wi-Fi and cellular that, while not cheap, are still within reach. If you hope to stay connected on a blue water passage, a satellite system may be in your future.