USS ARIZONA MEMORIAL
Submerged Cultural Resources Study:
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Chapter IV: Biofouling And Corrosion Study
(continued)


Bathycorrometer Measurements

A description of the methods used to obtain bathycorrometer measurements and a listing of the resultant measurements are provided in Table 4.7 of this report. A copy of the data has been given to metallurgical engineers at Pearl Harbor Naval Shipyard for analysis.

location of bathycorrometer measurements
Figure 4.12. Location of bathycorrometer measurements made on the USS ARIZONA.
(click on image for a larger size)


Table 4-7 Bathycorrometer measurements - USS ARIZONA

Method used for bathycorrometer measurements: Prior to dive ops, instrument was turned on and suspended in seawater for about 30 minutes for equilibration. Soft and hard fouling growth was scraped away from metal surfaces (about a 2-inch diameter area) and black and grey oxide coatings over shiny metal were penetrated. Preliminary measurements had shown that readings made on black and grey oxides (presumably composed primarily of magnetite and hematite, respectively) were not consistently the same as readings made on shiny steel - thus all subsequent readings were made only on clean steel.

Measurements on the USS ARIZONA were made on: 1. vertical exterior hull surfaces, 2. superstructure surfaces, 3. a few hull surfaces beneath silt line, and 4. at and just below water surface at a few superstructure sites. Additionally, a few measurements were obtained from gunnel and superstructure locations on the USS UTAH in the course of one dive.

Control/drift check measurements were usually made on a gunnel site on the USS ARIZONA that was located about midship on port side. Drift was generally in the range of 0.002 volt over the course of a 1 to 2 hour dive.

Other notes: Fouling thickness measurements (in centimeters) include is total thickness of live and dead fouling. Dead fouling on most vertical surfaces averaged 1 to 2 cm thickness. Most of that material consisted of oyster and vermetid mollusk worm tubes that adhered tightly to the underlying oxide surfaces. Exfoliated = irregular oxide/steel plates delaminating from hull. Some exfoliated areas may actually be areas where a double hull exists with gaps of 1 to 5cm between plates. Areas of active corrosion, exfoliation and "delamination" were actually rare on the hull and superstructure surfaces deeper than 5 feet below surface.

divers recording bathycorrometer readings
Figure 4.13. Scott Henderson and another diver record bathycorrometer readings.
(NPS photo by Larry Murphy)

VERTICAL STATIONS DATA

Note: Readings were made in closer area spacing on the forward port side of the USS ARIZONA. When it became evident that there was very little variation in readings, measurements were made only at tagged biological observations (numerical designation) stations.

STAFOULING (cm)BLACK LAYER (mm) VOLTSNOTES
Contr2 - 53 - 5.58716 Jul 85
602 - 85 - 10.579
612 - 65 - 10.583
A5 - 1510 - 15.585
B1.5 - 510.580
C1 - 810 - 15.581
D1 - 715.582
571 - 415.583
581 - 615 - 30.583
591 - 815 - 20.584
E1 - 35.587
F2 - 1315 - 25.586.592-17 Jul reading same site
562 - 10.591
G1 - 510 - 20.594exfoliated - hvy yellow
551 - 310 - 15.601
541 - 45 - 10.578
531 - 4<5.575
H.576
Contr.587stop 16 Jul 86
Contr3 - 825 - 30.589start 17 Jul 86
I1 - 51 - 10.579
J1 - 51 - 15.584exfoliating
K5 - 1510 - 20.583
L2 - 61 - 10.593
M5 - 102 - 10.592
01 - 35 - 15.592exfoliating
P1 - 415 - 25.569
Q1 - 25 - 10.574
R1 - 215 - 20.562
S1 - 420 - 30.571
T3 - 520 - 30.597exfoliating
U2 - 520 - 3.596exfoliating
521 - 725 - 40.592
51.584exfoliating
Contr.589
Contr2 - 510 - 25.588
V2 - 625 - 35.587
W2 - 6<5.591
X2 - 615 - 25.592
Y1 - 45 - 15.591gas
Z2 - 410 - 15.590
AA2 - 4<5.591gas
AB2 - 510 - 15.589
505 - 710 - 30.591
491 - 215.592exfoliating
481 - 410.587
471 - 410.591
462 - 610.596
452 - 65.590
442 - 65 - 10.592
432 - 65 - 10.591
422 - 65 - 15.588exfoliating
412 - 610 - 15.591
401 - 3.594
392 - 515 - 20.585exfoliating
381 - 410.587exfoliating
371-35 - 15.583
365 - 105 - 15.580
355 - 105 - 10.571
342 - 810 - 20.573
332 - 85 - 10.578
322 - 4<5.586exfoliating
312 - 3<5.574
302 - 410 - 15.581
29.591
Contr.588stop 17 Jul 86
Contr1 - 35 - 10.593start 18 Jul 86
281 - 35 - 10.586
271<5.593
261 - 410.600exposed scar
251 - 3<5.595
241 - 55 - 15.595
231 - 55 - 10.597
221 - 35 - 10.596
211 - 55 - 10.598
221 - 35 - 10.596
211 - 55 - 10.598
201 - 6<5.602exfoliated w/ 1cm gap
191 - 55 - 15.595
181 - 410.597
1735 - 10.593exfoliating
161 - 3<5.592
151 - 3<5.592exfoliating
141 - 3<5.588
131 - 45 - 10.596
1235.605
113 - 65 - 10.592exfoliated w/ 1cm gap
101 - 3<5.575
93 - 65.581
82 - 65 - 10.587
710<5.588
62 - 55 - 10.579
52 - 55 - 10.583exfoliated
42 - 4<5.588exfoliated
31 - 3<5.586.290 on grey layer
22 - 4<5.588
1.587exfoliated
50.594
49.598
48.590.587 previously

SUPERSTRUCTURE STATIONS DATA

STAFOULING (cm)BLACK LAYER (mm)VOLTSNOTES
Contr.59021 Jul 86
11 <2.568#2 gun ear
21 - 35 - 10.568#2 gun turret
32 - 610 (black/grey).579interior #2 gun turret
42 - 710.578interior #2 gun turret
51 - 410.569#2 gun turret
61 - 4<2.567#2 gun ear
71 - 22.586interior wall
81 - 65 - 10.586interior wall
92 - 4<2.561interior wall stack base
91 - 42/3 (black/grey).563exterior wall stack base
101 - 510 - 20.580ext wall stbd gun tub
111 - 33 - 5.574stbd #3 gun foundation
121 - 4<5.579exterior wall #4 gun found
121 - 2<5.576exterior wall #4 gun found
131 - 2<5.583aft ext wall stbd stairwell
141<3.580aft ext wall port stairwell
150.5<1.585center launch crane base
16--.641stern anchor scraping
170.110 - 20.583ext wall stern vent
1814/4 (black/grey).580ext wall forw stern vent
191 - 2<4.576ext port #4 gun foundation
191 - 410.576int port #4 gun foundation
201 - 25 - 8.574port #3 gun foundation
.616aft dock chain (recent?)
211 - 3?.581vent forward of #2 gun foun
221 - 63/10 (black/grey).585port ext wall gun tub
Contr.58921 Jul 86

SUBSILT HULL DATA

Note: Holes were dug into silt adjacent to hull at four locations on both port and starboard sides. Holes were about 2.5 feet deep and hull at all subsilt locations was found to be covered with layer of dead, hard fouling. Depth of bathycorrometer reading (below silt surface) is given in notes column.

STAFOULING (cm)BLACK LAYER (mm)VOLTS
Contr.59922 Jul 86
621 - 4<5.595Below sta VP1 - d = 1.5 ft
521 - 3<5.602Below sta VP4 - d = 2 ft
441 - 3<5.599Below sta VP7 - d = 2 ft
331 - 3<5.583Below sta VP10 - d = 2 ft
Contr.59322 Jul 86
Contr.59223 Jul 86
31 - 25 - 10.590Below sta VS1 - d = 1.5 ft
VS61 - 2<5.599Below sta VS6 - d = 1.5 ft
Contr.59223 Jul 86
Contr.59223 Jul 86
71 - 2<5.602Below sta VS7 - d = 2 ft
VS101 - 3<5.585Below sta VS10 - d = 2 ft
VS31 - 3<5.593Below sta VS3 - d = 2 ft
Contr.59223 Jul 86

NEAR-SURFACE TRANSECT DATA

These measurements were performed on superstructure pieces that penetrated the water surface. B = water line, C = 1.5 foot below water line, D = 3 feet below water line.

STAFOULING (cm)BLACK LAYER (mm)VOLTS
1B1 - 3<5.574
1C1 - 3<5.578
1D1 - 3<5.578
2B1 - 4<5.578
2C1 - 35 - 10.582
2D1 - 35 - 10.582
3B1 - 6<5.576
3C1 - 520 - 25.580
3D1 - 415 - 20.579
4B1 - 5<5.572
4C1 - 55 - 10.576
4D1 - 55 - 10.574
5B1 - 45 - 10.580
5C1 - 510 - 15.581
5D1 - 65 - 10.579
VS48.607
VS49.616
VS11.629
6B1 - 610 - 15.585
6C2 - 105 - 15.586
6D1 - 45 - 10.586
7B1 - 55 - 10.582
7C1 - 33 - 6.582
7D1 - 45 - 10.584
8B1 - 65 - 15.585
8C1 - 45 - 10.584
8D1 - 45 - 10.584

MISCELLANEOUS BATHYCORROMETER READINGS FROM USS UTAH

25 July 1986 - R. Scott Henderson

VOLTS
NOTES
.965On galvanized dive ladder in water.
.598On gunnel at bow.
.597On anchor chain hole in hull - port gunnel.
.599On vertical closed cylinder about 3 feet in diameter with cross-section like a keyhole. 1/2" black layer over steel 1/2" fouling.
.591Pipe-like structure with "crowsnest" on top - lying on deck, 5 feet north of BP20.
.588On jumbled steel beams and plate - corrosion/fouling as per previous station.
.588On block-like structure at CP60 that measures about 3' x 3' x 5' - very thin fouling over what appears to be bronze or brass.
.582Large superstructure surface - @E5 clip - black layer with some white laminations inside.
.578Objects on wood deck that look like "nuts" measuring about 8" x 8" x 3" high made of brass or bronze.
.585Round stack near clip P3.
.596Large diameter salvage cable about iS' NE of FS20.
.588Steel nearly exposed on hull by fish nest about 15' SW of FS20.
.590Gunnel at 6.
.593Bollard top at clip V7.
.290Reading in normal salinity seawater at about 5' depth.
.280Reading in lower salinity seawater near surface. No contact with solid substrates on these two readings.


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Last Updated: 27-Apr-2001