A recent news story about the 25th anniversary of an earthquake and tsunami that struck the Big Island reminded me of a tsunami alert given to O`ahu's boaters about six years ago.

At 6:30, one Tuesday morning, Waikiki's warning sirens began to wail after Civil Defense officials received word that a powerful offshore earthquake had rocked Japan.

Subsequent radio and television reports announced that a tsunami generated by that distant earthquake could reach the Hawaiian Islands by 10:30 that morning and residents were advised to follow the directions provided in their phone books.

For boat owners, the phone book's advise was brief: "All vessels should be secured, removed, or put out to sea due to the probability of strong horizontal currents, surges and wave action."

For most owners with boats moored in the Ala Wai Boat Harbor, putting out to sea was the safest and most expedient procedure and nearly a third of those did so.

Soon there were some 250 boats a mile or two offshore, milling about and waiting for the all-clear signal, or for disaster to strike their home port.

Joining them in their wait, out of Kewalo Basin and Honolulu Harbor, were vessels of every size and description, from dinner cruise ships and longliners, to tankers, tugs and barges.

At the time, I was not so much struck by the numbers of boats seeking safety, but by how many boats were still tied up in their slips.

Either their owners had very good insurance policies or the owners missed the gravity of the situation.

Eventually, it was determined that the earthquake had not created a tsunami and the all-clear signal was given. The numerous vessels that had fled their moorings returned and life around the marina went back to normal.

Nevertheless, the threat of tsunamis clearly remains. As the folks from Civil Defense say, "It's not a matter of if, it's just a matter of when it will happen."

Fortunately, Hawaii's boaters have more than a one-line warning in the phone book to guide their actions today.

About two years ago, the state's Division of Boating and Ocean Recreation, together with the University of Hawaii Sea Grant Program, produced the very comprehensiveHawaii Boater's Hurricane Safety Manual, which includes a four page section on tsunami education and survival.

The manual gives a 10 point list of suggestions under the heading of Tsunami Evacuation Plan for Boat Owners.

In brief, they are:

· If your boat is on a trailer, move it outside of the evacuation zone.

· If your boat is not trailerable, move it offshore to at least the 200 fathom line.

· Plan to have enough food, fuel and water for at least 24 hours.

· Do not move your boat offshore if you can't be at least 2 miles out from the channel entrance before the expected arrival of the tsunami.

· Have someone drive you to your boat so your car is not left in the evacuation zone.

· If your boat cannot be moved, remove whatever valuable items you can.

· Do not move your boat offshore if seasonal high surf would put you at risk.

· Plan to complete your emergency actions one hour before the tsunami's arrival.

· Plan on heavy traffic causing delays in travel time.

· Try to designate an alternate person to carry out your emergency plan.

For the more detailed manual, visit your state harbor master's office.