Rep. Bill Alexander, an Arkansas Democrat who learned to swim in the Mississippi River, shifted the heavy breathing gear, patted the knife on his weight belt and said to his companion: "Last chance to chicken out."

"No way," replied Republican Sen. Lowell Weicker of Connecticut, his 6'6" frame similarly equipped. One after the other, they plopped backwards into the crystal sea off Grand Bahama Island.

Thus began a two-day underwater adventure last week for the two lawmakers. Within minutes they had swum to the sandy bottom 50 feet below and entered a steel cylinder 16 feet long and eight feet around and anchored in concrete. "It looks," Alexander said of their algae-covered ocean floor home, "like a creature from somewhere else."

Weicker, 44, and Alexander, 41, are both experienced divers. They spent eight to ten hours a day exploring the Bahamian shelf—herding schools of grunt, a fish which may some day prove worth sea-farming, and observing the destructive effects on coral of chlorine in man-made pollutants. The underwater lab eliminates the need to surface after each dive, allowing more time for exploration. It is air-conditioned, dehumidified and has radio contact with the land every two hours.

Accompanied by two experts, Howard Pollock and Robert Wicklund of the National Oceanic and Atmospheric Administration (NOAA), Weicker and Alexander hope to draw attention to the Bahamas cylinder as the last active station for underwater research still funded by the U.S. government. "The truth is," explains Weicker, "the government is not doing anything about the resources of the oceans. Funding and coordination are zilch, but sure as God made green apples, the potential of the oceans is going to be realized in a year or two, and we want to be ready."

The expedition began with medical examinations and a briefing for the congressmen. Practical details were not neglected. "When you have to go to the bathroom," advised Wicklund, "take your scuba tank, swim out the hatch, and go behind a coral head." He also warned them when making coffee to remember that water boils at 230° at that depth. "You'll burn your tongue pretty good if you forget how hot it is," Wicklund said.

As for sleeping in the cylinder, into which air is pumped by a compressor aboard an unmanned boat anchored above, there were two bunks and limited floor space. The lanky Weicker chose the deck. "Those bunks aren't big enough to be a footrest for me," he observed, but rejected Alexander's suggestion that he save space by hanging his feet out the hatch in the bottom of the cylinder (a four-foot barracuda named Charlie was a frequent visitor to the area). Their diet was simple—cereal and peanut butter and jelly sandwiches, supplemented by any fish they caught. Their first efforts were a flop. But, optimistic, they asked that a bottle of wine be sent down for the evening meal.

After nearly two days of submersion, 15 hours of decompression awaited them before they could return to the surface. Weicker seemed in no hurry to leave. On the first day, peering out through a large porthole as a platter-shaped angel fish passed by and mirror fish and gray jacks cruised around, Weicker radioed to shore. "It's nice and quiet down here, the company's fine and I just had peanut butter and mayonnaise on a cracker for lunch. It's just heaven."