H.J.W. FAY Cruise 3

                                   October 2, 1975
                                         to
                                   October 17, 1975

                              Chief Scientist-John Schlee

Introduction

    As a part of USGS program to evaluate the subsea resources and the 
environment of the Atlantic OCS, a two week cruise was made to Georges Bank 
and Nantucket Shoals during the first half of October. The main purposes
of the cruise were to (1) investigate the shallow structure of the area (as 
a key to spot potential geologic hazards), (2) study of the deeper crustal 
structure through measurement of gravity and magnetics, and through seismic
reflection profiles, (3) to collect shallow seismic reflection profiles over 
areas where vibracores v:ere taken on the first cruise of the FAY.

    The cruise completed a survey with a 20 km line spacing (N-S) over the 
Bank with 3 tie 1,ines along the central northern and southern part of the 
Bank. Lines were extended into the deep ocean (1800 m) to assure coverage 
over the continental slope.

Participants

Ship:            John Ostensen    Captain
                 John Lero        First Mate
                 Jim Biller       Third Mate

Scientific:      John Schlee      Chief Scientist-USGS
                 Paul Cousins     USGS
                 Ellen Davie      USGS
                 Dennis Edwards   USGS
                 Peter Gleba      USGS
                 Prescott Heald   USGS
                 Frank Jennings   USGS
                 Mike Kerkmann    USGS
                 Stanley Locker   USGS
                 Felicity Oram    USGS
                 Perry Parks      USGS
                 Douglas Peeler   USGS
                 Fran Scarver     USGS
                 Dick Sylwester   USGS
                 Lyle McGinnis    University of N. Illinois

Equipment:

    We towed four sensors behind the ship, a 3.5 khz ORE fish (suspended on 
the starboard aft side of the ship, approximately 30 feet below the sea 
surface), a single channel minisparker, towed from a boom off the starboard
side near the stern, a single channel air gun system (towed astern), and a 
magnetometer-gradiometer probe (also towed astern). A four air-gun array was 
towed in two groups behind the ship; a 160 cu. in. air gun was towed by 
itself, to the port side astern, and a 3-gun array on a "fish" (80, 40, 
20 cu. in) was towed directly astern. Navigation was by two Internav 101 
receivers, with fixes taken every 15 minutes; Loran C readings were also 
fed onto paper punch tape every 10 minutes. For graphic display of seismic 
data, two UGR Raytheon recorders and two EPC Curley recorders were used. 
Filtered and unfiltered air gun, 3.5 khz and minisparker data were recorded 
on a 7 channel Honeywell tape recorder for later editing and analysis.

    A fifth system to measure gravity was installed in a separate van on 
the O1 deck. Gravity was measured using a vibrating string accelerometer 
sensor mounted on a gyrostabilized platform.

         Of all the systems, the gravity and magnetics proved to be the 
most free of breakdowns. The malfunctions of all systems are covered 
chronologically in the cruise narrative.

Cruise Narration:

- October 2, 1975 (275 J.D.)

     Depart Woods Hole at 1225 (GMT or z) and motored down Vineyard Sound to 
Gayhead; seas calm, skies cloudy, wind from northwest 20-25 knots, course 
236dT, speed 9.9 kts. By 1445 (z) Captain had decided to hold for the
weather (passage of Hurricane Gladys); gentle swells, 1-2 m. Deployed 
3.5 khz fish at 1514(z). The remainder of the day we motored in a triangular 
course southwest of the Elizabeth Islands, and in Vineyard Sound.

- October 3, 1975 (276)

     At 0710 (z) we left Vineyard Sound for Georges Bank. At 1230 (z) we 
began to deploy gear for beginning of Line A. 1445 (z) came to course 90xT 
to begin Line A; speed 61 kts. Minisparker not functioning for much of Line 
A. Completed Line A at 2345; began Line B.

- October 4, 1975 (277)

     Skies clear, sea spotted with whitecaps and a brisk wind. FAY had 
difficulty supplying adequate amount of salt water for cooling gravity van 
(temperature rose 5xC above normal value in hut), and flushing toilets. Ran 
Line B and part of Line C; began Line C at 1410 (z). Three airgun fish out 
of operation from 1434 to 2030; operated on 160 cu. in. gun alone. SEI 
streamer out of action for the slope part of Line C; switched to a new 
streamer.

- October 5, 1975 (278)

     Seas were calm, and skies clear and sunny. We completed Lines C, 
D and part of E. Perry Parks rigged up a new thermostat arrangement for the 
air conditioners in the gravity hut, and used the alternate unit to do most 
of the air conditioning. Both airgun units were pulled between 2002 and 
2336 for servicing. Even with this attention, 40 cu. in. air gun continued 
to bleed between firings (5 sec.).

- October 6, 1975 (279),

     Seas were calm, weather cool and skies cloudy. We completed Line E 
and part of Line F. We experienced power surges in ship's electric current 
which altered the time on the main clock used to mark the records. This clock
was out several hours until a voltage stabilizer was put in between the 
digital clock and the electrical outlet, to protect against the surges. 
Corrosion in the connector at the winch for the SEI streamer, caused it to 
be down from 1656-1910 (z); we used 100 Element Minisparker streamer over 
this time. Three airgun "fish" out for repair, 1321-1514.

- October 7, 1975 (280)

     Seas were choppy with a mild swell early in the day, deteriorating 
to 8-10 ft. waves and 40 kt. winds. Weather was cloudy and became sunny and 
clear as the day progressed. We completed Line F and started Line G. All 
systems operational except 20 cu. in and 40 cu. in. air guns.

- October 8, 1975 (281)

     Seas calm and weather partly cloudy to clear and sunny. We complete 
Lines G and H and part of I. Three airgun fish out of water for repair 
1224-1830; 160 cu, in. gun down from 0133 to 1224; air lines were replaced 
on two compressors.

- October 9, 1975 (282)

     Weather was clear and sunny. Seas were rough at night, moderating 
toward morning. We completed Line I and started Line J. Minisparker out 
because of erratically firing source and hydrophone malfunction from 
0900-1240 (z), 1309-1330, 1555-1918; a new amplifier-filter combination 
was set up. Loran C values were slewed because of a momentary power failure; 
both receivers stabilized ina manner similar to the digital clock. 160 cu. 
in. gun out from 0750-1524; three gun fish array out from 1210-1557.

- October 10, 1975 (283)

     Seas were calm and the weather partly cloudy. We completed Line J 
and part of Line K. Three air gun array retrieved at 0435 (20 and 40 cu. 
in. guns not firing). Fish bent at a welded point of repair. 80 cu. in. 
fish deployed separately at 1505. Fish (with 40" and 20" guns) abandoned.

- October 11, 1975 (284)

     Seas were calm. Weather sunny to partly cloudy. Lines K, L, were 
completed and Line M started. We experienced much ship traffic at the end 
of Line K, northern flank of Georges Bank. All systems Operational except
40 and 20 cu. in. airguns.

- October 12, 1975 (285)

     Seas were calm in the early morning but as the day lengthened, seas 
became rough (10-12 ft. waves); weather changed from cloudy to rain with fog. 
We completed Line M and N; pulled gear after completion of Line N (1505z) and 
motored slowly southeast of line into heavy seas. Only gravity was measured 
during this time of waiting for seas to moderate and fog to lift. Seas 
moderated in the evening (2000-2100 z) and we motored northeast toward the 
beginning of Line O. We had one close call while pulling gear, the "Cape 
Morrow", out of Halifax, passed within 50 yds of the FAY's port side. She 
was approached undetected on the FAY's radar because of "hash" on the radar 
screens caused by the agitated sea state. 160 cu. in. air gun out from 0222 
to end of Line N (1505z).

- October 13, 1975 (286)

     Cloudy weather, strong northwest wind (45 kts) came up in middle 
part of the day; 6-8 ft. waves. Sea state moderated toward latter part of 
the day. We commenced Line O at 0215 z. Gravity and magnetometer data were
noisy because of the choppy seas. All systems go except 20, 40, and 160 cu. 
in. airguns.

- October 14, 1975 (287)

     Seas were smooth with a gentle swell. Weather was warm, sunny and 
clear. We completed Line O, P and part of Q. 160 cu. in, airgun substituted 
for 80" gun at 0250; by 0610 (z) a 40" gun was also in the water. Upper
Loran C unit malfunctioned and was repaired.

- October 15, 1975 (288)

     Seas were extremely calm and weather clear in the early morning. 
We spent the 1200-1600 (z) watch manuvering on Line R in the fog to avoid 
fishing vessels. Lines Q and R were completed, and Line S was begun. All 
systems go except 20 and 80" air guns.

- October 16, 1975 (289)

     Seas were calm in the early morning, becoming slightly rough as 
the day proceeded. Skies were sunny with a high cloudiness and haze. We 
completed Lines S, T, U, V and W. Because of a malfunctioning of Channel 
7 on the tape recorder, we switched the minisparker input from this 
channel over to Channel 3. All systems operated normally except the 20" 
and 80" airguns. We completed survey at 2330 (z) and haul in all gear.

- October 17, 1975 (289)

     Seas were calm. Pulled 3.5 khz fish so FAY's clutch-drive train 
could be tested. Redeployed fish at 0054, but pulled it at 0106 because the 
10 kt. speed was too fast to tow it. Arrived in Woods Hole at 1110 z.