DAVE NORBERT has worked with sailboats since he was a child; he's good with his hands. John Full didn't work with sailboats until he grew up, but he's good with his hands, too.

Together they are building a boat that should be very good for all the hads who sail her.

In a shed thee very good for all the hands who sail her.

In a shed thebert and Full are spending their leisure time - something like 30 hours a week apiece - building a ketch-rigged 55-foot fiberglass sailboat. Two years from now they hope to have it ready to sail; three years from now they hope to sail it to the Caribbean; and some undetermined years from now they hope to sail it around the world.

The roots of the project trace back to the days when Norbert's father ran a marina in upstate New York. Norbert learned to like what he saw. Later he spent seven years in the Coast Guard and learned to like what he looked after.

About five years ago he began to put aside money for a boat and talked Full into a full partnership. In the beginning the partners looked around for a good used boat, but in the course of their travels they discovered that more than a few people, none of whom seemed any more capable than they, were building their own.

They decided to go that route, reasoning that self-construction would save so much money that they would end up with a much grander vessel than they had originally hoped for.

Both men deny their project requires any terribly sophisticated skills. Norbert, 37, a government telecommunications specialist, said the comparatively simple electrical circuitry and install the engine. And Full, 34, a UPI photographer whose father was a carpenter, figures to perform adequately with the wood and the fiberglass.

Both men insist that the requirements for manual dexterity are outpaced by the need for patience.

"We have a timetable for the overall project," Full said, "but you can't have one for every little job. We never rush anything. Take the transom, for example. It took us two weeks to do that. It's got compound curves that have to be put into wood and, believe me, it was frustrating figuring it out."

So absorbed are the two in the project that they feel guilty if they take a day off. Both work night shifts in their regular jobs, both say they can get along on six hours of sleep and both have decided to forego for awhile the wasteful pleasures that fill most lives. They show up at their shed at about 9:30 in the morning and go steadily for five straight hours.

Their labor so far has produced the framework for the hull. Soon the frame will be covered with foot-wide strips of C-Flex - parallel fiberglass rods encased at half-inch intervals in fiberglass cloth. Resin will be applied to set the fiberglass. Then additional fiberglass will be affixed to the first layer so that eventually the hull will be an inch thick from the keel to the water line and about a half-inch thick from the water line to the deck.

Except for the transom, all the internal wooden framework will be discarded when the hull is completed.

The partners are committing themselves to spending up to $50,000 in materials and equipment.

One costly item is the 20,000 pounds of lead ballast needed for the keel. "If we went out and bought it a retail," said Norbert, "we would have to pay maybe 24 cents a pound, which means about $5,000. We've discovered that the lead plate hospitals use to shield radioactive materials eventually loses its shielding capability without becoming radioactive itself. It sells for about 15 cents a pound.

"We wish we could use beer cans for ballast because a lot of them get emptied around here in the course of a day's work."

Such items and the value of their own labor add up in a hurry. When the 46,000-pound craft is finished the partners think they'll have something a boat manufacturer would have to price at $150,000.

In spite of their intense determination to see their project through, Norbert and Full are never too busy to talk about it.

"Saturday, in particular, is our public relations day," Full said. "We're usually happy to shoot the breeze with visitors who are interested in building their own boats. We've got people coming down here who know more about what we're doing than we do - and if we take time to chat, some of them will probably give us answers to questions we have ourselves."

Getting there is easy. Head east on Duke Street to the dead end at the Potomac River. The second building to the north - an aluminum structure painted bright blue - is where the great boat is slowly growing.

Since creation of that sort is very thirsty work, a gift of a few cans of beer might not be a bad idea. It will probably lead to a guided tour - which may even inspire the visitor to the same dream that possesses Norbert and Full.