Select Page

Surveyors gather data to estimate the likely life span of the slowly deteriorating Arizona

art

GREGG K. KAKESAKO / GKAKESAKO@STARBULLETIN.COM
Les Hardy, owner of Geodimeter Southwest, entered data collected by $38,000
surveying equipment that uses lasers and prisms to measure angles and distances.
Hardy donated his time last week to help National Park Service staff collect
information that will be used to create a digital 3-D model of the midsection
of the USS Arizona.


Over the past six years, National Park Service teams
have used everything from high-tech global positioning system devices to pre-World
War II construction drawings to make sure the USS Arizona Memorial doesn’t
break up.

Working under a $ 800,000 federal historic preservation
grant from the Pentagon, the program helps the National Park Service and the
Navy determine when and if it should to intervene in the natural deterioration
of the battleship.

The latest venture for the past week has been a $ 38,000
survey system donated by Trimble Corp. and the volunteer services of Les Hardy,
who heads Geodimeter Southwest. A team of eight divers, national parks staff
members and volunteers have been at Pearl Harbor surveying 80 feet of the
Arizona’s sunken deck using lasers and other methods.

The data collected, according to Douglas Lentz, USS Arizona
Memorial superintendent, will be compiled with other information from the
National Institute of Standards and Technology to construct a complex 3-D
computer model, called a finite element model, to help predict the battleship’s
life span.

‘That will help to determine the window when the ultimate
collapse will occur,’ Lentz said.

The 3-D computer model will digitally reconstruct the
608-foot battleship starting from the day it was sunk by a Japanese dive bomber
on Dec. 7, 1941. The effects of the fatal blast from a 1,760-pound armor-piercing
bomb from one of 183 Japanese airplanes, which ignited its forward ammunition
magazine sinking the battleship within nine minutes, are then factored in,
along with other variables such as 60 years of immersion in salt water.

Five years ago, divers with high-powered nail guns fired
43 stainless steel nails into the ship’s deck. Archaeologists and surveyors
measured the longitude, latitude and elevation of each nail with GPS receivers.

This time, using sophisticated laser surveying equipment
and traditional methods of measuring and mapping points on the Arizona’s sunken
decks, the National Park Service is updating its information.

Since the Arizona is not just a sunken warship but a
maritime tomb for the remains of more than 900 sailors, officers and Marines
of the battleship’s 1,177 crew who were killed on the ship in 1941, the divers
never go inside the hull of the vessel, said Jim Bradford, program manager
for the National Park Service.

Even the white 184-foot memorial, which spans the midsection
of the sunken battleship, does not touch the ship.

Instead, the park service has sent tethered, remotely
controlled vehicles into the vessel and has used ultrasound on the bulkheads
to measure the thickness of the hull and compare it to the original specifications.


art

GREGG K. KAKESAKO / GKAKESAKO@STARBULLETIN.COM
National Park Service divers Pat Smith, left, and Matthew Russell prepared
to install prisms for the laser survey system near the bow of the USS Arizona
that was used to help collect data on the condition of the framework of
the vessel.


When the Arizona, commissioned in 1916, sank in 1941,
there was almost 1.4 million gallons of fuel oil in its storage bunkers.

Conservative estimates suggest that as much as 500,000
gallons of oil still remain in the battleship.

Brad Baker, Arizona Memorial park ranger, said, ‘It is
critical to be able to determine as closely as possible just how long the
battleship will remain intact before disintegrating and releasing oil into
Pearl Harbor.’

Matthew Russell, underwater archaeologist with the Park
Service’s Submerged Resources Center in Santa Fe, N.M, has headed the USS
Arizona Preservation Project since 1999. The National Park Service has maintained
a hull assessment program since 1983. Members of the USS Arizona Memorial
Dive Team also conduct dives every two weeks to monitor and record the condition
of several cracks on the deck of the ship, to remove objects accidentally
dropped by tourists and to recover and deploy monitoring instruments.

‘By the end of 2006 we hope to complete work on the research
portion,’ Russell said, ‘and come up with our management resource recommendations.’

Diving into the waters surrounding the Arizona over the
past six years, ‘you see something different with each dive,’ Russell said.

Russell said this week he noticed ‘quite a bit of new
sea growth and coral’ clinging to the hull of the battleship.

‘This could be indicative of improvement in the water
quality of Pearl Harbor over the past decade,’ Russell added. ‘This might
help to reduce the corrosion rate.’

Jim Koza, a retired park service employee, made his first
dive on Tuesday into the nearly 400 feet of murky water where the Arizona
sits.

‘Visibility was anywhere from five to 10 feet,’ said
Koza, a Vietnam War Navy veteran. ‘Everything would change as the wind moved
the waves about.’

After his 5 1/2 hour dive, Koza added, ‘It was a just
an honor to be asked to participate in this dive.’

Source : starbulletin.com

Share This