Heading into the usually busy Memorial Day weekend, lifeguards at one of Oahu's most dangerous yet popular South Shore beaches are now better equipped to warn people of the risks.

A four-speaker public address system that lifeguards say is much more effective than hand-held megaphones was recently installed at Sandy Beach Park. Two speakers face Sandy Beach, while the third is pointed toward the Blowhole and the fourth toward Makapuu.

Lt. J.R. Sloane, who monitors beaches on Oahu's South Shore for the Ocean Safety and Lifeguard Services Division, said that from the beach's lifeguard tower, the sound from the speakers can be heard at the surf lineup more than 100 yards away from the shoreline. “;You could hear this all the way down to Blowhole. It's so much louder.”;

With megaphones, warnings were muffled by whipping winds and crashing waves.

“;You couldn't really understand what they were saying. Now the sound is much crisper,”; said lifeguard Capt. Kevin Allen. “;The people in the water can hear it much better.”;

In the last two years, lifeguards on the South Shore spoke about the need for such a system as the number of rescues at Sandy exceeded the rate at Makapuu Beach.

Sandy is known to have the highest rate of neck and back injuries in the nation due to its dangerous shore break.

Last year the beach saw 472 lifeguard rescues. From 2004 to 2008 the rate of lifeguard rescues at Sandy's more than doubled, according to Dan Galanis, epidemiologist of the Department of Health's Injury Prevention and Control Program.

This is the third public address system to be installed at Oahu's beaches. The first was at Waimea Bay several years ago with the second at Hanauma Bay in recent months.

Costs for the systems were unavailable from city officials.

Custom Audio, owned by John Schneck, installed the three systems and is expected to install a fourth system at Sunset Beach.

The system at Waimea Bay was upgraded last December with stainless steel hardware, which was also used in the other two systems on the South Shore. The speakers have a range of a football field.

“;The battery-powered megaphones don't throw sound the tenth of what the speakers can do,”; said Schneck, adding the speakers are loud enough to be heard over the surf.

“;This system is designed to be powerful enough to withstand the worst weather conditions,”; he said.

North Shore Ocean Safety Capt. Bodo Van Der Leeden said the three-speaker system is an invaluable tool for Waimea Bay lifeguards.

“;It's a godsend. It made a huge difference to the effectiveness of rescue prevention,”; said Van Der Leeden.

During the winter, many spectators flock to Waimea Bay to view the enormous waves, creating a hazard when many stand near the shoreline.

With the speaker system, lifeguards can easily warn the crowds to steer clear of the shoreline during high surf.

“;You can immediately get their attention with the PA system,”; Van Der Leeden added. Warnings also can be heard by surfers at the lineup at Waimea Bay about 300 yards away from the shoreline.