Surfers aren't so sure.

The state Department of Land and Natural Resources is planning to replenish sand on Waikiki Beach by sucking sand up from the ocean, collecting it in offshore beds and pumping it onto the beach in three areas.

The question is whether the prevailing current moves parallel to the beach or flows straight out to sea. A flow toward the sea would carry sand from the beach and deposit it back on the ocean floor, which surfers believe could affect the waves.

About seven ounces of fluorescent dye were poured into the water near the Duke Kahanamoku statue every 30 minutes over a 12-hour period to see where it flowed.

"We are seeing the dominant direction of transport is along shore toward the Royal Hawaiian, and then out the rip current in front of the hotel," said Dolan Eversole, a coastal geologist with the Sea Grant Extension Service. "So far today we haven't seen any dye moving straight offshore."

George Downing, a founding member of the group Save Our Surf, wasn't buying it.

"Water is not sand," Downing said. "The experimentation should be with sand granules, not with dye and water. This doesn't prove their point to me. What they got to prove is what happens to the sand itself, not the water. I think this thing is ridiculous."

Downing said he expects the sand will move straight offshore, fill in below surfing areas and end up on the beach in front of the Royal Hawaiian and Moana Surfrider hotels.

"It will definitely affect the surfing spots," Downing said.

Eversole said, however, that the test is useful.

"Generally, the sand is going to mimic the water. Whatever we see the water doing, the sand is going to do the same pattern of movement."

The $500,000 sand replenishment project is expected to begin in late October or early November, and take 20 to 30 days. It will bring up about 10,000 cubic yards of offshore sand.

State officials hope the technology will become affordable and practical enough to be used across the state, as it is on the Mainland.

A barge will be moored about 2,000 feet offshore above a sand bank identified in a University of Hawai'i survey as having plentiful, clean sand. The barge will be equipped with a hydraulic sand dredge and connected to a submerged pipeline system to the beach.

The pumped sand will be allowed to dry; then heavy equipment will push it where sand is needed on Kuhio Beach.

Downing was among surfers and residents who attended a Sept. 1 public meeting and asked that the state conduct more tests to follow the movement of sand, especially from the area in front of the statue, known as Site 3.

Eversole said the 2- to 4-foot swell off Waikiki yesterday gave a good example of what the currents will do.

"The best thing we can do is try to gauge and understand what it does most of the time," he said. "We know that a larger proportion of the sand will move during a swell, so we were waiting for this day to gauge it."

This type of dye testing is frequently used to follow currents and sand flow, he said.