U. S. Geological Survey Open-File Report 01-154
Cruise Report - R/V Gosnold 49
|PURPOSE:||Bottom sampling and photography to test the camera in the big bucket.|
|DESTINATION:||Continental shelf between Cape May, New Jersey, and Cape Hatteras, North Carolina', continental slope and rise between Cape Hatteras, North Carolina, and Northeast Channel, off Georges Bank.|
10 August 0800 to 12 August 0900
Woods Hole: 23 August 0830 to 24 August 2000.
|1 August 1964 - 0930 to 29 August
1964 0956 - 1530
Full length of cruise:
Jobst Hulsemann (WHOI, in
1 - 10 August:
12 - 23 August:
24 - 29 August:
Secure bottom sample, measure total volume, take two one-pint representative sediment subsamples, one of which is marked for the archive, take about 250 cc surface sediment subsample to which an alcoholic Rose Bengal solution is added (= Foram. spl.); wash remaining sample through a1 mm screen and save the coarser fraction in a 7% Formaldehyde solution (= Biolog. spl. and gravel); take a BT-cast, take weather observation, water transparency and color; check camera system, obtain position of ship. In general, two party members are on watch.
Summary of time schedule: Days/Hours/Minutes
1 August - Leave the home dock at 0930 after radar equipment has been repaired. Pass through Vineyard Sound and go on SSW course. Sunny sky turning to overcast, the wind increases to a fresh breeze during the night. Rig sampling equipment and instruct party members on sampling procedure.
2 August - Continue on SSW course. The wind is from the S at 15-20 knots. Start routine bottom sampling at lat. 38¶50'N 74¶30'W at 1815 with station no. 2025. The strobe light flashes independently from mercury switch trigger, Wet electrical contacts are dried and cleaned. Similar trouble with strobe light on subsequent stations.
3 August - Continue bottom sampling. On station 2030 the trip lead weight is caught by the grab on the first drop. Overcast, drizzle; the wind changes from NE to Z, increasing to 25 knots. It becomes more and more difficult to secure a sample. On station 2038 first drop no trip, two subsequent drops are waterhauls. On station 2039 the volume of three drops totals some 5 liters of sand. The wave height is now about 3 m, the wind from the Sup to 40 mph. The grab is secured, the ship is hove to.
4 August - Heavily pitching in sea, waves breaking on deck. The wind is from NE up :o 45 or 50 mph (estimated). Hove to in vicinity of station 2039. From 0910 to 0925 surface water plankton tow between stations 2038 and 2039. Wind moderating during the later part of the morning. Occupy the next station at about noon time. It is partly cloudy, the wind from E, force 4 to 5. Pull strobe unit and camera for checking and repair. Continue routine sampling on pattern off the Virginia coast. Wind and sea further moderating.
5 August - Continue routine sampling off the Virginia coast. Mostly sand bottom and little recovery of sediment by the grab. Frequently, the grab comes up to the surface with the electrical cables, protected in a rubber hose caught between the jaws. Apparently the trigger weight causes some imbalance and is pulling the grab co one side. Reduce the lead weight by removing the bottom part under the compass. Further checking of strobe and camera equipment, chiefly drying the contacts. Strobe continues to flash irregularly. Moderate swell and light breeze from S, partly cloudy to sunny.
6 August - Finish the major part of the sampling pattern on the continental shelf with station no. 2165 near Oregon Inlet, North Carolina, some 35 miles north of Cape Hatteras. Traverse the shelf to the continental slope off the Cape Hatteras Coast and start sampling using the Campbell grab. Initial attempts to recover a bottom sample fail. In two cases the reason is an incorrectly assumed -echo- depth, thus the grab is not lowered to the bottom, in other cases the grab tripped prematurely. The echo depth is extremely difficult to read from the PDR: even ''full gain" produces but a faint record with little discernible trace.. Use of the pinger has helped to reveal when the bottom was struck by the grab. Its application is limited, however, because it is not synchronized with the PDR and can only be traced by ear. Between the termination of the sound signal, after the pinger has been tilled off the vertical position when it comes to lie on the bottom, and the decrease of load on the cable tensiometer when the grab itself strikes the bottom, it is easier and more reliable to recognize the event ''on the bottom" from the tensiometer. Freeing the trigger rod which has been held up accidentally after a camera service prevents further premature tripping due to the heave of the ship. At a formal meeting the captain informs scientists and mates that the main cable will have to be cut instantaneously upon such a command issued by the bridge personnel. This is to be a precautionary measure in case the load of the cable, which on station is being shifted from one side of the ship to the other, shall cause a hazard co the ship. In water of more than 1500 m depth a snatch block is used on the main cable, it pulls the wire back and lowers the pivot point: from the sheave on the davit to the deck provided wind or current, whichever is the stronger - is kept on the port bow. In this manner the center of gravity of .the ship is moved to a more favorable position near midship.
7 August - Continue routine bottom sampling along the continental slope and rise off the North Carolina and the Virginia coasts. Here the sample depth extends to about 3000 m. In good weather there appear to be no difficulties. The wire is paid out at a rate of 85 meters per minute with little reduction near the bottom. The striking of the bottom is read on the tensiometer, which relaxes by some 200 to 350 Ibs at this time. Occasional heaves of the ship, unfortunately, can cause similar load reductions. Therefore, some 50 m excess wire is paid out beyond what was assumed to be the indication of the bottom to assure adequate slack wire. The final "wire depth" of the grab is read on the meter wheel at the instant the grab is pulled off the sea floor. At this time the load on the tensiometer may raise significantly, e.g. from 1900 to 2700 Ibs at a wire depth of 2500 m (figures refer to grab with stereo camera installed). The speed for hoisting the grab is controlled by the electric power for the winch: the current should be kept below 120 amp. This yields an initial speed of 30 to 40 mpm, which can be increased to 80 to 90 mpm with less than 1500 m of wire out. Attaching and removing the snatch block to and from the wire when the grab is just under the hull of the ship requires the least effort and takes about 4 to 6 minutes, but is a potential source for broken fingers in its present arrangement. Pumping water out of a ballast (#3) tank and flooding the tank while cable is paid out or reeled in, respectively, presents no problem. Due to this technique the list of the ship can be kept to less than 5 degrees." The recovered bottom material from the slope (and upper rise) is chiefly a green to grey mud. Occasionally, it is true foraminiferal ooze overlying a stiff grey clay (-rock. Pleistocene?) and with indications of allochtone material like sand grains, gravel, and pieces of twigs. ~ The biological contents is scarce. Polychaete worms are the most abundant animals besides foraminiferans. Numerous otoliths are found in several places, and pieces of pogonophoras.- Following station 2075 at 36o 15'N and 74o 30'W several patches of up to 100 m diameter of almost brown surface water are observed within a few hundred meters of the ship. The water color is typical for plankton blooms.
8 August - Continue routine sampling. Again difficulties with the strobe light (working irregularly). ((Also the need to load cassettes with (bl.&w.) film on board causes trouble which could easily be avoided by use of patrons or a sufficient number of cassettes loaded prior to the trip.)) SW wind picking up during the day to force 5. The echo sounder produces only faint traces in spite of lots of good will manipulation. Thunderstorm and rain showers in early night.
9 August - Continue routine sampling, working towards NE. Wind diminishing and turning westerly. Sky clear, air and water temperature a pleasant 20 and 22 , respectively. Continue to have difficulties with strobe and camera units. Plate for safety pin on grab heavily bent on first drop at station 2099, yet grab returned in "open" position. This is the only recent failure for the grab to trip at the bottom. Discontinue sampling after a short profile of 4 stations up-slope from 1250 to 300 m water depth S of Baltimore Canyon. Run for fuel stop to Cape May, New Jersey. On route take two shelf samples.
10 August - Continue on course to Cape May, New Jersey. Berthed at U. S. Coast Guard Base at 0830. Mr. Bruce Burns, Michael Page and Arthur Wegweiser leave the ship for return to Woods Hole by land transportation. The remaining scientific party is engaged in repair and servicing of the camera and strobe light units and, with help from U. S. Coast Guard personnel, the loran receivers
11 August - Berthed at Cape May. ((Preparation of station location plot of next leg of cruise for bridge personnel)) Drs. Roland Wigley and George de Vries Klein and Mr. James Coplan board the ship and join the scientific party.
12 August - Depart from U. S. Coast Guard Base, Cape May, New Jersey at 0900 heading towards continental slope. On route take one more shelf sample completing therewith the shelf sampling program of this project. Resume routine bottom sampling on the continental slope east of Baltimore Canyon. - Overcast sky changing to sunny with some haze. The wind is from SSE at force 3-4.
13 August - Continue routine sampling on slope. Wind changing to NW and increasing to force 4-5. Ship heavily pitching. Great care is necessary to prevent that a wave washes the sample out of the tub or the screen while it is processed and the ship underway. The formerly bent and now broken plate for the safety pin on the grab is now fixed by ship's crew. Working E of Wilmington Canyon towards NE.
14 August - Continue routine sampling between Wilmington and Hudson Canyon. A sampling depth of 3000 m is attained without any difficulty. Commonly, the grab recovers between 50 and 100 liters of green mud, sometimes stiff clay. The fraction coarser than I mm is generally less than one quarter of a pint. Foraminiferans are the most abundant animal group within the biological fraction. There are strikingly few larger animals." The wind during this day is mainly from the W at force 4-5. Slightly heavier than moderate seas cause at times heavy pitching of the ship. The snatch block on the main cable at deck level shows signs of heavy wear. The winch generator had a few short failures during the evening (clogged fuel line?).
15 August - Continue routine sampling SW and NE of the Hudson Canyon. The sediment consists chiefly of green mud and clay. Members of the phylum pogonophora are very abundant. Also, many samples contain numerous squid beaks, and several of these are rather large.- There is light wind from westerly directions and a cloudless sky.
16 August - Continue routine sampling between Hudson and Block Canyon. Considerable effort is spent on the stereo camera system without success: batteries and electron tubes are changed, cable ends cleaned and dried, cables exchanged, rubber cement used and removed from connections, yet the system does not function properly when put together although the individual parts check out alright. ((I suspect creep currents due to salt bound moisture cause shorting; thus drying would be the answer)). Take a surface water plankton tow at station 2138. The wind is from SW at force 2-3, clear sky, moderate swell.
17 August - During the night passing of a low pressure system with wind from E and rain. Continue sampling between Block and Atlantis Canyon. Changing cloudiness and some rain, wind shifting to SW increasing to force 4. Again, considerable time is spent in an attempt to make the camera and strobe units work " without success ((1 man/almost around the clock for a day, (John Schlee)).
18 August - Continue routine sampling in Atlantis - Veatch Canyon area. Depths to 3000 of are obtained without difficulties. The most exciting individual sample is encountered on station 2150. Beneath a thin surface of brown foraminiferal mud follows a layer of green foraminiferous mud and then, with a rather sharp contact a layer of pale-yellow soft rock of clay grain size. A test with acid proves it to be highly calcareous. This rock is well indurated and abounds with drill holes of worms (and pelecypods ?); many holes carrying a black carbonaceous (?) coating. In places lumps of the pale yellow material are in sharp contact with pastel green rock of the same softness; some mottling is possible. A few lumps consist of solid green material. The major fossils recovered are three about 3-5 cm long singular hexacorals (grown together), reminiscent of the group of dendrophylliids. However, the rock also resembles some Cretaceous material as it can be seen at Gay Head on Martha's Vineyard. Thus the age is tentatively estimated to be Cretaceous or Tertiary. The grab haul also contains some gravel, apparently admixed of the recant green mud - near surface material. The echo sounder record does not indicate a signal which would normally be interpreted as characteristic for an outcrop of a layer, although subbottom reflections at a depth greater than the grab can penetrate could be inferred. Additional bottom sampling in this area and seismic profiling shall be rather prolific.
19 August - Continue routine sampling to the S of Hydrographer Canyon. When reeling in the cable on' station 2154 the break of one strand (out of 14) of the main cable is noticed at about 2130 m above the end of the cable. After removing a short section of the broken strand (about 50 cm) the "open" ends are taped co the main cable with pieces of friction tape. More careful inspection of the cable in the vicinity of the break area shows that it is rubbed blank and distinctly worn regarding the little use it had since it was new. The wear of the wire is attributed to the use of the various snatch blocks, which are temporarily rigged at deck level when the depth exceeds 1500 m. By now the third or fourth sheave is in use since the slope work started on the 6th of August. It appears likely that the principally used sheaves are too weak and/or too small for the wire. Also, there is some question whether the present rigging is very intelligent. Radio advice from Woods Hole (J. Leiby/R. Edwards) is to continue the work with the damaged cable. A part of the broken strand is secured as a sample. On board it is noticed that the fracture zone coincides with a position on the drum where both rollers of the level wind are driven by the incoming wire, about 2/5 the length of the drum from the right side. It is also noticed that the drum with the hydro cable rotates frequently together with the main drum. The engineers keep breaking (and cooling) it.- The camera unit and strobe light have been dried in front of the electric heaters while the two doors to the deck were kept closed. Henceforth, the camera equipment works again.- The PDR burnt some calibration mark generator bulbs and fuses. Repair accomplished partly using ship's parts (fuses).
20 August - Continue routine bottom sampling on continental slope and rise in the vicinity of Hydrographer and Oceanographer Canyon. Inspection of the cable about the breaking area at 2130 m shows only little wear of the friction tape.- Sampling in water depth of about 3000 m is done in about 1-3/4 to 2 hours. The weather is very favorable: very little wind from W and NW, a light swell and pleasant temperature to work on deck and with lots of water. Again the ship sails occasionally through patches of plankton concentration. From the distance .these patches appear as green water and contrast with the surrounding blue color. On a closer look the (phyto-) plankton appears as masses of brown color .and with a fibrous texture. A bucket sample is secured on station 2130. The camera and strobe unit continue to work after drying the instruments in front of the room heater while the doors are kept closed. A strong current sets the ship to the S at a speed of about 2 knots requiring special maneuvers during the hoisting of the grab. While on station in the early evening several (more than 10) dolphins are playing around the ship. Crew members fish and land about 2 or 3 on deck. Half an hour before midnight arrival on station 2165. The echo trace approaches 3820 m as the ship stops and then vanishes due to a.failure of the PDR or Gift sonar (no outgoing signal). This is to be the deepest station for any grab lowering aboard Gosnold so far.
21 August - While the grab is lowered attempts to locate the echo sounder trouble fail. The wind has picked up and the heave of the ship makes it difficult co recognize the arrival of the grab at the bottom. The maximum amount of cable paid out is 4070 m. Strong load increases on the tensiometer which could be indicative for a 'pull out and interpreted as the wire depth are observed at 4056 :n and again between 3820 and 3760 m. The value of 3820 m is believed to be the best one because at this reading a slight drop of load was noticed when the grab went down. Also, this depth value is in fair agreement with the ship's position on the newly compiled 1:1 million topographic map. The value does not agree well with the last reading on the echo sounder record, which is the same as the suggested wire depth although it is usually 100 to 150 m less than the wire depth. The discrepancy may be explained in the ci'.ne lapse of I hour between the last echo reading and the landing of the grab at the bottom. During this time the ship may have drifted towards shallower water. After the grab is retrieved the strobe unit is found to be imploded. Evidently, the failure started at the well for the "on-off' switch, which is in the geometric center of the strobe case deformation. Previously, there were about 6 stations with a water depth exceeding 3000 m, and the station immediately before this ill-fated one reached a depth of about 3400 m. The failure was not anticipated since a calculated collapse depth was given to be 3840 m with a certain yet unspecified safety factor, and since similar but rather weaker flash units had been test-collapsed at equivalents to 3820 to 4070 m. On the other hand the breakage did not really come unexpectedly. The broken unit is returned in the grab and used as ballast. The sediment is different on this and the next, about equally deep station: reddish brown foraminferous mud somewhat mottled with gray mud. The voluminous samples (80 liters each) contain numerous pebbles, poorly rounded, varying in color from dark to light - perhaps from basalt to granite. Some of the rocks bear animal growth indicating their exposure on the sea floor. The round trips for the more than 4000 m cable paid out require between 2 and 2~ hours on station. No further difficulty with the cable is noticed. The friction tape around the fracture zone at 2130 m wears only slowly. The wind turns to SW and increases to force 5 during the day, but shifts to the NE in the night diminishing to force 3.
22 August - Continue routine bottom sampling on the continental rise and lower slope to the SE of Oceanographer Canyon and then on the upper slope westwards to Hydrographer Canyon. When approaching shallower water, i.e. depth less than 2500 m, the broken strobe housing, camera case and trigger unit are removed from the grab. Terminate this leg of the cruise with a plankton tow on station 21/7. Set course to Woods Hole for fuel stop at 1450 EDT.
23 August - Continue running towards Woods Hole, partially in fog. Moored to R/V Crawford at home dock at 0825. Unload geological samples. Drs. Wigley and deVries Klein, and Mr. Coplan leave the scientific party.
24 August - Replace Gift sonar, and replenish geological sample containers. Insert two heavy lead weights (each more than 75 Ibs.?) into Campbell grab instead of the camera equipment. Drs. Corwin and Hazel, and Mr. Haynes board ':ha ship an~ join the scientific party. Depart from home port shortly after 2000 EDT Sailing through Vineyard Sound towards Oceanographer Canyon.
25 August - Continue sailing towards Oceanographer Canyon. Light swell of 1.3 m height from the S; it is calm or very light wind from SW. The visibility is limited by fog or haze to 2 to 3 miles. Rig sampling gear and familiarize new party members with procedures. Resume routine bottom sampling just east of Oceanographer Canyon at 2100. PDR develops a new malfunction: this time it is the breakdown of the paper take-up motor.
26 August - Fail to repair paper take-up of PDR. Thus the instrument is turned on only shortly before arrival at a new station and while the grab is lowered. There are several unsuccessful drops with the Campbell grab resulting in recovery of little bottom material, sometimes not more than what could be scraped off the walls of the grab that had failed to close. Modifications which remained unsuccessful include: removal of a one inch bolt from near the top of one of the grab halves to permit the escape of air (previously, all holes needed only in conjunction with the camera equipment were bolted with the idea to reduce the loss of sediment before the grab is opened over the tub), tying a rubber band to the T-bar to accentuate the downward pull during the tripping, latching the trigger rod in a position so that the catch would not support the T-bar, and removal of the "safety'-chain between grab hook and grab. Several links of this chain show fresh signs of wear (blank metal) as if it may have been entangled with a piece of the grab and prevented the full release of the main (pulling) cable. Following station 2184 the heavy lead weights from inside the grab are removed. This brings the grab almost back into the same condition in which samples were secured on the 22nd of August after failure of the stobe light unit. Yet success is still waiting. Scrapings from the wall of the grab indicate silty and muddy bottoms. The washings of some samples produced few small animals. Among others recovered are 1 ophiuroid, small pelecypods, forams, and otoliths. Test drops of the grab on deck do not reveal any malfunction: it always trips. But on several drops the grab is raised about 10 m off the bottom after the initial hit and dropped again two additional times - no lasting success. After midnight the captain decides to leave the proposed sampling track to stay in closer distance to the safe port of his choice (Boston, Mass.) in case hurricane Cleo would continue to run N along the Atlantic coast. With every additional station, however, the ship comes closer to Yarmouth, Nova Scotia, an alternate port for an emergency call suggested by the home port office prior to departure for this leg.
27 August - Thus bottom sampling continues on the continental slope between Georges Bank and the New England Seamounts (Physalia Seamount), working towards NE. All during the night bad weather; rain and thunderstorms with wind forces up to 6 on the Beauford scale. The weather clears in the morning, the wind diminishes to almost a calm. The sky is clear.- A final modification is thought to bring the grab to perfect balance (and behavior): removal of two pigs of lead mounted to the outside of the grab and re-installing the two heavy lead weights inside the grab. The limited success of grab recovery, however, changes to reliable results only after recognizing the speed of the lowering and in particular for the striking of the bottom to be the critical point. All subsequent drops are successful when the approach to the bottom is done at a rate not exceeding 30 meters per minute on the odometer. Thus the procedure for the routine lowering calls for a fast drop at a rate of about 100 mpm. to about 50 m less than the echo sounder depth, then a stop of the winch for about 1. to I minute to permit the grab to steady itself (observe steady value of the tensiometer); then precede to the bottom at not -more than 30 mpm. In this manner record recoveries of bottom sediment of 150 liters (maximum capacity) are not rare. In the early afternoon the captain asks for further modification of the cruise track in favor of a withdrawal to Boston although the port of Yarmouth is now about 10 sailing hours closer to the ship. Former hurricane Cleo, now reduced in strength to a tropical storm, continues to move slowly north on the Atlantic seaboard. A deadline for leaving tha working area on the continental slope SE of Georges Bank is set for the evening, postponed to the night and (at midnight) finally ordered for 0400 on the next morning.
28 August - After the sample on station 2196 is secured at 0435 EDT the course is set to WNW (280¶) to pass the Georges Bank region on the south side facilitating a later swing to the north towards Provincetown (1) or Boston. There is almost no wind and no sea, only a light swell of about 1 m from the W: ideal weather conditions for sampling, particularly in this area. The decision of the captain to terminate the work on the continental slope here and now in view of the reports on tropical storm (former hurricane) Cleo and to run for Provincetown or Boston makes little sense, is hardly justified on objective grounds, and shows poor understanding of the mission of the ship. It is by no means necessitated. The best one may say for it is it did not hurt anybody. The captain's reason to run for Provincetown or Boston and not for Yarmouth is his claim it would cause too many difficulties to have the scientists reenter the United States due to lack of some birth certificates. It is a fact, however, that no such documents are required when the ship calls at a foreign port due to an emergency. Of course, the ship had not intended to go into Yarmouth unless there was an emergency situation. A realistic evaluation of the situation looks about like the following: in the early morning hours former hurricane Cleo cannot be considered to behave like the majority of the hurricanes in the area; it is unusual in the sense that it is weaker, moves slower ahead, and turns away from the coast more directly that what is established to e the usual path. The weather forecast for the immediate working area for the next 24 hours is extremely good. Following the proposed sampling pattern had brought the ship within the next 24 hours less than 100 miles from Yarmouth thereby almost completing all programmed stations. A few additional hours (about 6) would suffice to finish the program entirely. If contrary to any predictions and indications former hurricane Cleo would gain strength and momentum and speed on a more usual track resulting in a potential danger to Gosnold, the ship could reach at any time the port of Yarmouth in between 10 and 20 hours less running time than the port of Boston, which means about one day's gain. In addition, Yarmouth lies farther to the N, away from the origin of Cleo and the course towards this pore would lead more directly away from the approach of Cleo. Mid-morning radio reports state that former hurricane Cleo appears to break up and take a turn to the NE out over the Atlantic (e.g. Fall River 13:30). At noon the position of Gosnold is about 30 miles south of Georges Shoal (41o 14.5'N 67o 43.1'W). The weather is good; no wind, clear sky. The course continues to be NW towards Pollock Rip Light Ship with the intention of turning more towards NW after passing the shoals, heading for Provincetown - Boston. With a fair current the speed of Gosnold exceeds for a few hours in the morning 10 knots. A radio message from the home port office at che scheduled traffic hour (1600) orders Gosnold to proceed directly co Woods Hole confirming indirectly the uselessness to run for Provincetown or Boston in order to seek shelter. The request to deviate to Wilkinson Basin and to take another sample is granted. This means a delay of about 7 to 8 hours to Woods Hole from the present position
29 August - At about 0400 arrival on the last station on voyage 49 with number 2197 in the Wilkinson Basin at a depth of close to 300 m. With to grab hauls more material than to fill two 30 gallon plastic barrels is recovered and sampled in order to provide a clay-rich marine sediment for the Standard Collection or the USGS. 50 liters, of the original material are passed through the 1 mm screen and the coarse fraction is sampled separately. Shortly before 0500 the course is set for Woods Hole by way or the Cape Cod Canal. Fog and drizzle prevail in Cape Cod and Buzzards Bay. Moored to Dyers Dock at: Woods Hole at 1715 EDT. All samples and portable equipment are unloaded by 1830 EDT.
CAMERA COMMENTS & SUGGESTIONS:
General: This rig is much less reliable than the one used a year ago. The fewer successful bottom photos (as seen in developed black and white film) attest to this. Though essentially the basic arrangement of components as the single camera unit, the redesign over the winter has worsened what was a passable piece of equipment. No one part of the system fails continually. It may be one or several parts in combination which cause the failure.
Hulsemann has attributed some of the difficulty to the constant dampness in the air around the components. His experience with a malfunctioning pH meter on shipboard (Cuss 1) led him to suspect the humidity and therefore to work in an air-conditioned van; under these conditions, the meter worked. In our case, he warmed both the strobe and the camera unit before the electric heater on one occasion. The system worked after this, prior to implosion of the strobe case. If humidity does cause some of the trouble, the inclusion of a cloth bag filled with 'drierite" in the strobe case and the camera case might help. Several of these bags could be kept in a dessicator in the ship, and changed in the camera case every time the film was changed. Strobe unit could be serviced over longer intervals.
Strobe Case: With this piece of equipment, the main trouble appeared to be the short wire of the 240 volt battery. The battery was changed several times during the cruise. Apparently the long time that the unit was switched on during the trip to the bottom and back, and the marked decrease in temperature caused; the bakery to run down. We don't really see why the battery should run down because it only had to light a neon bulb. Perhaps current leakage at the joy plugs or in the heater filaments of the tube causes the drain. Anyway, drain due to some sort of leakage and influenced by time and possibly temperature, draws the battery below the high threshold level necessary to operate the unit. One battery was tested in the lab, and operated the flash immediately after the switch was turned on, but would not operate it after the unit had been on for 15 minutes. A new battery remedied this situation when the same test was performed.
Camera: The camera in the position nearest to the relay tube did not fire on every impulse from the trigger. This was due to several known and perhaps some unknown factors. The trigger batteries had to be absolutely fresh (see trigger section). Brass trigger arm was bent slightly so that solenoid plate was brought closer to the magnet; this helped when used in combination with the set screw on the end of the arm. Strangely, the orientation of the camera and bracket: in space seems to influence whether the camera is actuated.
One difficulty - multiple flashing of the strobe - was caused by internal shorting of wiring in the camera case. In particular, the wires that plug in the front of each camera were shorting. The solder joints in one of the plugs were shorting because they touched; joints were resoldered using less solder on each connection. The other plug and wire were internally shorted. In this case, the difficulty could not be detected by a volt ohmmeter resistance check. Apparently the wires shorted only when the full load of the strobe battery was applied. A new wire and plug took care of the trouble. In addition, plastic tubing (spaghetti) should be checked carefully to see that the ends of the joy plugs are completely covered by the tubing.
Trigger: Though the camera unit is basically the same design as last year, the setup has another solenoid co operate, and hence the trigger using the same number of batteries as last year, lasts less time. This tends to create a high operating threshold for the batteries, a level below which the batteries fail to operate the two solenoids. A battery with more power (milliamps?) is needed. The cold temperature (35-45 F) in which these batteries operate may reduce their efficiency.
Leads: Outwardly, the use of joy plugs would appear to offer advantages over the double plugs used last year because of their design. They have not worked out as well for several reasons. There are six single-prong connectors exposed to possible leakage of current to seawater, rather than two double prong connectors. The prongs into which the connectors plug are easily bent and a bent prong could reduce the tightness of the seal made by the connector. Even though the single wires were fed through a piece of hose to keep them out of the bucket jaws, the arrangement did not keep them out and the wires were pinched and insulation broken, salt water leaked in and shorting occurred.
The remedy with the existing connectors is to use a small amount of "Scotchkote" on the bottom of each plug to prevent any possible leakage of salt water. Extra plugs of rope were inserted in each end of the hose to give more thickness at the points of attachment in each part of the bucket (under fiber brackets); this arrangement prevented the hose from coming loose and getting caught in the bucket.