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Figure 33: "Falcon" preparing to pass air hoses to top of stern pontoons.
"S-51" about to enter dry dock.
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Two divers now went down to examine the sill for lines astern of the "S-51"
before putting the caisson in place. They found two lines which had originally
been the towline to the "Falcon" and the preventer towline to the "S-51's"
bow; these were hauled clear of the sill and the caisson put in place.
Pumping the dock commenced, and the "S-51" soon landed fore and aft. Another
examination by divers showed everything clear along the keel (blocks had been
removed to clear all pontoon chains).
Before going further it became necessary to straighten up the ship. A wire
line was passed around the remains of the mast just above the periscope shears
and from this a heavy tackle run to the port side of the dock and around a
fourfold purchase to a capstan. A 10-inch manila line was taken down by one of
the divers and tied around the gun mount just forward of the conning tower.
This line was lead to the port side of the dock through a block to the main
fall of a 50-ton dock crane. A third line, but somewhat smaller, was secured
to the towing fair-lead aft and also lead to port.
As a preventer to avoid letting the ship roll to port after she straightened
up, a heavy manila line was run from around the base of the mast to the
starboard side of the dock, where it was tended on a capstan.
Everything being ready, the three port lines were heaved in gradually and the
ship came up slowly, perhaps 10 degrees, when the 10-inch line to the gun
parted on the dock and the other lines had to be slacked away; the "S-51"
rolled back to her original position.
The broken ends of the 10-inch line were tied together and another pull taken
with practically the same result. The 10-inch was then discarded and a diver
took down and shackleed a 2-inch wire line into the chain bridle around the
gun. This line was taken to the crane, but on taking a heave it was noted that
as the vessel came up the strain on the line increased instead of decreasing,
as might have been expected, since the free water inside the boat (which was
causing the list) was free to adjust itself to each new position as the ship
came erect and the heeling moment should have been zero with the ship
upright.
The block through which the 2-inch wire line was passed threatened to carry
away the straps holding it to the dock when the "S-51" was still over 10
degrees from erect; consequently everything was slacked back, and while a
heavier block and wire lashings were being provided, the problem was attacked
from another angle.
It was deduced that as the "S-51" straightened up, the starboard No. 3 pontoon
and the starboard No. 1 pontoon (but especially the former) touched the deck
of the submarine, and any further straightening of the submarine resulted in
lifting these two pontoons out of water, while the port side pontoons were
being correspondingly submerged against the force of their buoyancy; as the
stern was rounded on top this did not happen in the case of the No. 4 pair of
pontoons. This would account for the increasing strain on the hauling lines as
the "S-51" straightened up.
To overcome this, the four interfering pontoons were flooded a little to
reduce their pull and then with lines to the starboard side of the dock, the
No. 1 starboard and the No. 3 starboard pontoons were hauled enough to
starboard to get them clear of the deck.
When the new block for the 2-inch wire line was ready, another pull was taken
and conditions were improved. The "S-51" was gradually hauled up until she
was practically vertical, keeping a good strain on the starboard preventer
line to see that she did not go by that point. The ship was purposely held
with a list of 1 degree or 2 degrees to starboard and the dock pumped down a
few feet. Another preventer line was run to starboard and then all bilge
blocks hauled. These were considered unreliable, and further pumping ceased
while four pairs of divers on each side went down and started shoring up under
the bilge keels.
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Figure 34: "S-51" entering dry dock.
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Figure 35: "S-51" in dry dock. (Note arrangement of pontoons.)
----------------------------------------------------------------------- Page 86
This shoring was completed late in the afternoon, when pumping was resumed
until the deck showed about one foot above water. (See fig. 36.) Then the
pontoon chains were released from the pontoons and the latter hauled clear.
Two long oak shores were run from the dock to the starboard side against the
deck.
Work now ceased and no further pumping was attempted, since it was too late
for the medical party to start a search inside the boat and it was not desired
to leave the interior forward (where most of the bodies were expected to be)
exposed to the air longer than necessary.
On the morning of July 9 the dock was quickly pumped down and a number of
additional shores placed under the bilge keels. (See fig. 37.)
The salvage job was now completed. (See fig. 38.)
An inspection of the "S-51" in dock after unwatering resulted in the finding
of the bodies of 2 officers and 16 men. Some bodies were found in every
compartment from bow to stern. As 9 bodies had previously been recovered by
divers and 3 men survived, it appeared that 6 members of the crew were
missing, having managed to escape from the boat but only to drown outside.
Structurally the "S-51" was found with a large gash resulting from the
collision (see fig. 39) and with a deep wrinkle in the shell in way of the
torpedo room bulkhead (see fig 40). In addition the bow, which had been
intact during salvage operations and during the tow, was torn away by the
towline shackled into the bullnose when the "S-51" hit Man-of-War Reef. (See
fig. 41.) This carried away the upper part of the stem casting and the
starboard shell plate riveted to the stem; these pieces were hauled aboard the
towing tug with the towline. (See fig. 42.) The bridge structure, which was
very light, was originally bent slightly to port by leaning against the
starboard No. 3 pontoon after the events of June 22. It was found that this
contact had torn off the valve on the upper end of the voice tube from conning
tower to bridge, and it was the loss of this valve which resulted in making
the C.O.C. nonwater-tight on July 5. (The end of this voice tube was easily
accessible, and it could have been quickly plugged had it been found necessary
to seal up the C.O.C. to raise the boat.)
The bridge itself was found badly bent to port from leaning against the
starboard No. 3 pontoon when the "S-51" nearly rolled over while aground in
the East River. (See fig. 43.)
The main keel was bent and there were numerous dents on the starboard side
below the bilge keel where the vessel had grounded on the reef; there were no
ruptured plates from this cause. (See fig. 44.)
Aside from the above, there was no other major damage nor was there any
deterioration of hull or indications of corrosion, electrolytic or otherwise.
The exterior paint was intact, with only light marine growth in spots. The
interior paint was peeling in spots, but without corrosion. All cork
sheathing was, of course, water soaked and loose.
No corrosion or deterioration of the Diesel engines or other machinery had
taken place; cleaning and oiling was all that was required for functioning
again. Most surprising of all, the large electrical motors throughout the
ship were found in condition to run after washing, cleaning, and baking. Many
of the ship's circuits were found, however, with water inside the armor;
renewal here was required.
The main battery cells were found intact; no signs of explosion or
deterioration from chlorine gas or acid were visible. The cells and
connections were in good shape, but the lead plates required renewal.
After making temporary repairs to the hull, and such preservation work on
machinery as was immediately necessary, the "S-51" was floated out of dock on
her own buoyancy to await action on reconditioning. (See fig. 45.)
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Figure 36: "S-51" on blocks. Deck about 1 foot above water.
----------------------------------------------------------------------- Page 88
Figure 37: "S-51" in dry dock.
Dock pumped down and bilge shores in place.
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Figure 38: Divers who salvaged "S-51".
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Figure 39: Detail view of gash
resulting from collision with "City of Rome".
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Figure 40: Port side view showing wrinkle caused by
bow striking bottom after collision with "City of Rome".
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Figure 41: View showing damage to bow caused by
grounding on man-of-war rock.
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Figure 42: "S-51" bow plating and stem casting on board "Sagamore".
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Figure 43: View of bridge badly bent to port
from leaning against starboard No. 3 pontoon.
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Figure 44: Damage to bilge keel and main keel
due to grounding on man-of-war rock.
(Note pieces of stone on bilge keel.)
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Figure 45: "S-51" afloat on her own buoyancy.
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The foregoing is a brief description of the conditions found, the methods and
materials used, and the difficulties encountered in salvaging the "S-51" and
bringing her 150 miles to dry dock. For future operations, it is possible
that the experiences set forth above may be of value. But for a correct
estimate of the whole job, it is desired to state that the success of the job
was far more due to the courage, the energy, and the devotion of the men
engaged, both as divers and on deck, than to the material. Human endurance
was always the limiting factor; it was badly stretched in salvaging "S-51".
For the next operation of a similar nature, the most important feature is to
provide the men in adequate numbers; the material can always be quickly
fabricated.
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APPENDIX A
The diving crews on the "S-51" were composed of the following men:
FALL OPERATIONS, OCTOBER 16 TO DECEMBER 6, 1925
Anderson, George, rigger.
Bailey, Henry, gunner's mate, first class.
Carr, William Joseph, boatswain's mate, first class.
Eadie, Thomas, chief gunner's mate (reserve).
Eiben, Joseph, chief torpedoman.
Frazer, James W., chief torpedoman.
Ingram, James C., chief torpedoman.
Kelley, J. R., chief torpedoman.
Michels, Fred George, chief torpedoman.
Smith, Francis G., chief torpedoman.
Wilson, Raymond C., chief torpedoman.
SPRING OPERATIONS, APRIL 26 TO JULY 8, 1926
Anderson, George, rigger.
Bailey, Henry, gunner's mate, first class.
Boyd, David H., torpedoman, third class.
Carr, William J., boatswain's mate, first class.
Clark, G. W., seaman, second class.
Davis, A. H., torpedoman, second class.
Eadie, Thomas, chief gunner's mate (reserve).
Eiben, Joseph, chief torpedoman.
Ellsberg, Edward, lieutenant commander (C.C.).
Grube, Carl, seaman, first class.
Henry, E., torpedoman, third class.
Holden, G. F., torpedoman, first class.
Ingram, James C., chief torpedoman.
Kelley, J. R., chief torpedoman.
Madden, Jos. C., rigger.
McLagan, E. M., gunner's mate, first class.
Michels, Fred G., chief torpedoman.
Sanders, S. A., chief torpedoman.
Smith, Francis G., chief torpedoman.
Wickwire, William S., gunner's mate, first class.
Wilson, Raymond C., chief torpedoman.
The following men made one dive each on the job and were then forced to quit
for various reasons:
Anderson, Frank, shipwright.
Applegate, C. L.,(1) coxswain.
Clark, A. D., seaman, first class.
Clemens, Harry R., seaman, first class.
Dewberry, T.,(1) chief torpedoman.
Horan, H., torpedoman, first class.
L'Heureux, J. W., torpedoman, first class.
McNeil, Andrew R., torpedoman, third class.
-------------------------------------------------------------------------------
1 Made four dives.
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APPENDIX B
Plate 10 is a general arrangement plan showing the proposed layout of
submarine rescue vessels based on recommendations made in the case of the
U.S.S. "Falcon" after the completion of the salvage of the "S-51".
---------------------------------------------------------------------- Page 100
APPENDIX C
DIVING OPERATIONS IN CONNECTION WITH SALVAGE OF THE "S-51"
(From report of Lieut. Henry Hartley, commanding officer, U.S.S. "Falcon")
1. In commencing the spring operations on the "S-51", the marker buoys that
were planted at the end of the fall operations having dragged out of position
during the winter, it was necessary to locate the vessel by grappling. The
nature of the grapnel catches was ascertained by sending down a diver. When
the catch was identified as the "S-51" a diver attached a buoy line to the
vessel and made a report as to its general position. After determining the
approximate heading of the submarine, the planting of necessary moorings was
undertaken. Manila hawsers of 8-inch circumference and 120 fathoms long and
two 4,000-pound and four 6,000-pound anchors were used for this purpose. It
was decided to plant one mooring ahead, one mooring astern, and two bow and
two quarter moorings 50 degrees from the ahead and astern moorings. Buoys were
first planted to indicate the desired location of the moorings. The marker
buoy was passed close aboard with the "Falcon" heading in the same direction
as the submarine. A cork buoy was planted over the wreck, three ship lengths
from the marker buoy. This operation was repeated on the opposite heading and
on the four other desired compass headings. When all of the markers were
placed the moorings were planted in the locations marked by the buoys. By this
method the six moorings were planted by the "Falcon" in three and one-quarter
hours.
2. After the moorings were planted the first diver used the marker buoy line
as a descending line, taking with him a 3.5 or 4 inch manila line which was
secured to the vessel and buoyed at the upper end for permanent use as a
diver's descending line. The boat boom was guyed aft as far as the rigging
permitted and the after boom was guyed forward, both booms being topped up so
that a single whip from the boom head would clear the vessel's side about 2
feet. Four-inch single lines, marked every 10 feet, were run from the winch
to a block at each boom head. The lower ends of these lines were fitted with
eye splices and screw shackles. Two stages, 3.5 feet square, were made from
flat bar and fitted with iron bails, about 6 feet long, to each corner and
rigged so that they could be slung from the booms.
3. The divers were dressed near the places where the stage whips plumbed,
there being provided for this purpose small benches or dressing stools fitted
with shelves under the seat for the small tools, breastplates, washers, nuts,
etc. While the divers were being dressed, the hose and telephone cable were
made ready, hooked up, and tested. When the diver was dressed and had tested
his own 'phone, he mounted the diving stage and was hoisted over the side
clear of the rail. The stage was then dropped until the diver was submerged a
foot or so below the surface. At this point the stage was stopped until the
diver had tested his air and telephone and checked the water-tight integrity
of his diving dress, etc. If any defects were found, the diver could be
hoisted aboard on the stage in a very few seconds. When the diver reported
ready, the stage was led to the descending line. After any material or tools
he was to carry down were given him, he left the stage and descended on the
descending line, the tender paying out hose and cable as the weight of the
diver took it. This permitted the diver to stop his descent at any time, and
thereby control his descent. However, he was not allowed to descend at a rate
greater than 1 foot per second, as he must take the necessary precautions to
build up his air pressure as he descends. The time required for descent varied
with the individual, but
---------------------------------------------------------------------- Page 101
for 135 feet slightly over two minutes was the average time of descent. When
the diver reported that he had reached bottom, his working mate was put over
and lowered in the same manner.
4. At all times when divers were down one diver was kept on deck fully
dressed except as to his helmet and ready to descend in case of emergency.
This is considered of the utmost importance in all deep-sea diving.
5. When the diver reported ready to ascend or when he had been down the
allowed maximum length of the time, he was told to come to the descending
line. The descending line was passed through a screw shackle attached to the
diving stage and the stage lowered to the proper distance. The diver was
hauled up by his tenders at a rate of about 1 foot per second and landed on
the stage. After the first diver was landed his mate was brought up in the
same manner. When both were on the stage, the stage was unshackled from the
descending line which was then clear for the other diving stage. The
timekeeper, who was an experienced and reliable chief petty officer, kept a
record of the time the diver reached and left the bottom, and the time for
decompression. After the diver had mounted the stage the rate of ascent was
governed by the decompression table in the Diving Manual, except as noted
herein.
6. The routine which was carried out in getting the diver out of cold water
as quickly as possible after one hour at 132 feet was as follows:
(a) The stage was first lowered to 80 feet. After receiving the diver's
report that he was safely on the stage, the stage was held at certain depths
for various periods of time as follows:
Depth: Time (minutes)
80 feet ............................................ 4
70 feet ............................................ 6
60 feet ............................................ 8
50 feet ............................................ 10
----
Total ....................................... 28
(b) After the 10-minute decompression at the 50-foot depth the stage was
hoisted as rapidly as possible and the diver landed on deck. About 20 seconds
were then required to remove the diver's belt, shoes, and helmet, after which
he was assisted into the outer lock of the recompression chamber, undressed
and given dry clothes, hot coffee, etc., and passed into the inner chamber.
About two minutes from the time he started from the 50-foot stage were
required to get the diver under pressure again. The initial air pressure in
the recompression chamber was stepped back one stage (equivalent to water
pressure at 60 feet) and then held at the various stages, indicated below:
Air pressure equivalent to: Time (minutes)
60 feet ............................................ 10
50 feet ............................................ 12
40 feet ............................................ 15
30 feet ............................................ 18
20 feet ............................................ 20
10 feet ............................................ 25
----
Total ....................................... 100
7. The medical officer kept strict watch over the divers' diet and physical
condition. Colds, indigestion, minor attacks of bends, or too long a stay in
the water on the previous day usually rendered one or two divers unfit for
work. It was necessary to exercise considerable care to insure the divers did
not overstrain themselves due to overzealousness and pride in their work. The
amount of work the men were called upon or allowed to do was governed by the
physical condition and experience of the various individuals. In assigning
work extreme care was taken
---------------------------------------------------------------------- Page 102
to assign the easier tasks to the more inexperienced divers in view of the
psychological effect of failure upon the morale of the individual.
8. Diving could not be carried on when the ship was rolling as much as 10
degrees or 12 degrees as the pumping up and down of the diver on the stage
injured the eardrums and caused nausea. Working under unfavorable weather
conditions or at night was profitless, and except in emergency the work
accomplished did not compensate for the wearing effect on the divers.
9. The number of divers and the number of dives per day, etc., involved in
the spring and fall salvaging operations of the "S-51" were as follows:
-------------------------------------------------------------------------------
Fall | Spring
operations | operations
-------------------------------------------------------------------+-----------
Total days ............................................ 50 | 68
Days one or more dives made ........................... 21 | 51
Days weather prevented diving ......................... 29 | 17
Total number of dives ................................. 226 | 374
Average number of dives per diving day ................ 7.8 | 7.33
Maximum number of divers available .................... 11 | (1) 24
Minimum number of divers available .................... 5 | No record.
-------------------------------------------------------------------------------
1 Only 15 of these men were used. The others after making one or more dives
were disqualified due to their being physically unable to stand the strain.
10. The minor difficulties encountered on the job are too numerous to cover
fully and many of them were of themselves inconsequential. However some of
the experiences may be of interest and some of the observations may be of
benefit in future operations of this nature and will, therefore, accordingly
be cited:
(a) Too great importance can not be given to the question of satisfactory
telephones, diligent and intelligent tending, and judgment and experience of
the officer in charge of the diving. As an illustration of the value of the
necessity for vigilance and initiative on the part of a tender, one instance
may be cited. On May 21 the man tending the telephone called to the tender to
haul the diver up quickly. The tender thus warned called for help and several
men assisted him to haul the hose and cable. As a result of this prompt
action, the diver was alongside the ship and all hose and cable in when he
emerged at the surface. The diver was quickly hauled aboard and decompressed
in the tank with no ill effects. When the telephone man was questioned he
stated that he had only heard what he thought was a "frightened squawk."
(b) On three different occasions the tunnels caved in while divers were
working in them and in one case the diver could not free himself. There were
also three cases in which the divers' lines became fouled and the divers were
unable to clear themselves. In the latter part of the fall operations
considerable difficulty was experienced due to the air lines freezing and two
cases of complete stoppage of air to the diver occurred. In both cases quick
action prevented any serious effect on the diver.
(c) There was one case of caisson disease from which the diver recovered
after several weeks in the hospital. It developed during his first descent.
The hose became fouled and he was unable to clear himself with the result that
he probably got excited and frightened and overtaxed his strength. In another
case where the diver overexerted himself he developed heart murmurs and was
restrained from further diving. There was one case of a slight rupture to one
ear drum due to the failure to build up proper air pressure during descent.
Further diving by this diver was also prohibited. One diver also developed an
attack of bends of such severity as to disqualify him for further deep diving
on this particular project. The ship's records show 13 cases where divers
were treated in the recompression tank for bends serious enough to
incapacitate them for one or two days.
---------------------------------------------------------------------- Page 103
(d) Under normal conditions divers were limited to one dive of a maximum
length of one hour daily. During the fall operations in the endeavor to
complete the salvage before the weather made further diving impossible, divers
fit for duty made two dives of about one hour each daily. The physiological
effect of this on the divers was very marked and toward the end of the
operations from 50 to 75 per cent of the divers were incapacitated each day
due to mild attacks of bends or colds. It is probable that with the dives
limited to one per day, a greater number of hours on the bottom could have
been secured. Ordinarily, if a diver remained on the bottom over one and
one-half hours, he was not permitted to dive the next day. The longest time
on the bottom by any diver in a single dive during the entire operation was 3
hours and 13 minutes. The maximum permissible time can be varied somewhat
with the individual, but until a man's capacity and endurance is well known,
the one-hour period mentioned above should not be exceeded.
(e) The use of the decompression chamber in deep-sea diving offers many
advantages. It permits the diver to get into dry comfortable clothing in a
place where he can rest, attended by a medical officer, and be given food and
drink as necessary; thus contributing to his comfort and the safe-guarding of
his health. It reduces by 50 per cent the actual time divers are submerged,
thereby permitting the availability of almost double the number of divers for
work on the bottom.
(f) During the fall operations the divers started work using the regular
rubber cuff and snapper and were usually fully decompressed on the stage. Due
to the reduced circulation of blood in the wrist and hand caused by the
snapper and the exposure of the bare hands to the cold water for long periods,
the hands become numb, causing considerable discomfort, and as the weather
grew colder attacks of bends became more frequent, with the result that toward
the end of the operations practically all the divers working regularly
suffered attacks of bends. During the spring operations the regulation tender
two-finger stall and thumb molded gloves were cemented direct to the sleeve,
avoiding the discomfort experienced in the fall. In addition the procedure
for decompressing outlined above was used, reducing the time the diver was in
the water by about 50 per cent. A very remarkable reduction in the number of
cases of bends reported was noted.
(g) Much could be said about various methods of sending gear, tools, and
material down to the diver, but there are so many variations due to the
classes and characteristics of material to be handled that no discussion can
be complete. However, it is considered essential that in securing and sending
gear below every effort should be made to facilitate the removal of the
lowering gear and eliminate all unnecessary effort on the part of the diver.
The tender who superintends this work should be an experienced diver in order
to avoid fouling the diver's hose and lines, prevent delays, and assist the
diver on the bottom to the maximum extent possible.
---------------------------------------------------------------------- Page 104
APPENDIX D
MODIFICATIONS TO SALVAGE PONTOONS
1. The design of the pontoons used on the "S-51" salvage operation was
prepared for the pontoons which were used in raising the "F-4" from 46 feet of
water in Honolulu Harbor. Owing to the shallowness of the water in which they
were used, no particular difficulty was experienced, but it was reported at
the time that the cylinders showed a decided tendency to become unmanageable
and heavy as soon as the water-plane area had vanished. The urgency of the
requirements for pontoons in connection with the salvage of the "S-51" was so
great that no attempt was made to alter the design used in connection with the
construction of the pontoons for the "F-4" and six additional pontoons from
these plans were built at the navy yard, New York.
2. The report of the salvage operations describes the difficulty encountered
in handling the salvage pontoons when submerged partially filled with water.
The difficulty encountered was due to the fact that the pontoons on
submergence had negative longitudinal stability. This resulted from the loss
of external water plane after submergence in combination with a large internal
free surface, the pontoons at this stage being about two-thirds full of
water. As a result of this condition the pontoon immediately upon submerging,
unless restrained, had a strong tendency to upend and remain in a vertical
position.
3. During the salvage it was determined by experiment that the pontoons with
a negative weight of 10 tons had sufficient water inside to reduce the
internal free surface to the point where the pontoons could be lowered
horizontally. However, handling the 10-ton load was a more or less difficult
operation, and the flooding of the pontoons to the proper stage involved some
danger of injury to the personnel operating the flood valves. These
difficulties were very much increased by rough weather.
4. Another difficulty experienced with the pontoons was the loss of lift due
to taking an angle in the raising operation. When the vessel being lifted
took an angle as one end lifted, the submerged pontoons at the other end took
nearly the same angle. The effect of this was to leave in the high end of the
pontoon a considerable amount of water below the flood valves on that end
which could not be expelled. This condition is indicated on Plate No. 5.
5. In order to correct these defects it was decided to cut out the existing
athwartship bulkhead and build in its place two bulkheads so placed as to
divide the pontoon into two similar end compartments and one middle
compartment. The bulkhead spacing was chosen so that when the two end
compartments were completely flooded and had therefore, no free surface and
the central compartment was completely dry, the pontoon would have about 3-ton
negative buoyancy. In this condition the pontoons act as fixed weights and
can be lowered in essentially the same manner as any other dead weight. A
sluice pipe with a valve was provided between the two end compartments so that
when it was determined which end of the submerged vessel was to be first
lifted, the flood valve in the end of the pontoon which would rise first with
the boat could be closed and the sluice valve opened. With this arrangement,
all the water can be blown out through the flood valve at the lower end and
the entire buoyancy of the pontoon realized.
6. Plates 8 and 9 show the salvage pontoons after being altered in accordance
with the above. These alterations have been actually completed on salvage
pontoons YSP 5 to 10, inclusive, but have not been undertaken on YSP 1 to 4,
inclusive. The negative buoyancy of the pontoons as altered, with the end
compartments filled and the center compartment dry, has been determined by
test to be approximately 6,000 pounds.
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