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All air was immediately sent to the six forward pontoons, and blowing was
continued on them, as a group until at 2:45 p.m., when several air discharges
at various spots forward showed that some of the pontoons were already dry.
The pressure on the bow telltale hose had shown a slight increase as the bow
sank in the mud when the stern rose, but it did not now show any tendency of
the bow to lift.

At this time the "S-50" reported all the air in her high-pressure banks used
up; she started up both her compressors, while the "S-3" maneuvered to come in
alongside the "S-50" and run a high-pressure air line to her to help out.
(See fig. 22.)

Meanwhile air was shut off all the six bow pontoons and then admitted to them
through one hose at a time to test their condition.  It was found that the No.
1 pair and the No. 3 pair were venting air from both forward and after ends
and were consequently blown down to their limit.  It was also found that the
after ends of both pontoons in the No. 2 pair were venting air and were
therefore also completely blown down.  There remained only the forward ends of
the No. 2 pair which were not yet blown dry; still it was recognized that even
these must be nearly dry, as they had received about as much air as the other
forward pontoons.

All air was now concentrated on the two hoses leading to the forward ends of
the No. 2 pair.  The situation was tense, as nearly an hour had gone by since
the stern rose, and it was known to all the crew from the air just discharged
over the bow that the pontoons there were apparently all dry.

Blowing was continued at reduced speed, since the "S-3" was not yet hooked
up.  The gauges on the lines to the forward ends of the No. 2 pair showed a
steady increase in pressure in the pontoons; water was being forced out and no
air was being discharged at the surface.

At this stage, at 3 p.m., it was noticed that the gauges on the No. 1 pair of
pontoons, which had been steady for some time, suddenly dropped 4 pounds, and
then continued to drop in pressure.  A glance at the surface showed no
indications whatever, but it was certain that the bow was rising and the men
were so informed.

About 10 seconds later, the surface became turbulent over the entire length of
the submarine and probably in 20 seconds more a number of geysers formed and
the remaining six pontoons broke through the surface, floating practically
level and spaced exactly as intended.  (See fig. 23.)

On the surface, the six forward pontoons blew themselves clear of the residual
water in their after compartments; no blowing from the "Falcon" was found
necessary.

The air was put on the forward group of fuel-oil tanks at once and this group
was soon blown clear.

Boats from the "Falcon" and "Vestal" ran alongside the pontoons and secured
the flood valves and hoses for towing.  The "S-50" and "S-3" shoved off and
ran clear; the "Falcon" dropped astern of the "S-51" and took the stern
towline from the "Iuka".  The "Iuka" steamed out and took station in tandem
ahead of the "Sagamore".  (See fig. 24.)

At 4.20 p.m., the tow got under way headed northwest, as follows:

"Iuka" leading with a 100-fathom towline to "Sagamore"; "Sagamore" with 100
fathoms on each of the two forward lines attached to "S-51", towing on the
line shackled into the bullnose and with the line secured to the gun as a
preventer; the "Falcon", 150 feet astern of the "S-51", with the "S-51's"
stern line lead over the "Falcon's" bow to prevent the "Falcon" from dropping
too far astern and parting the 20 hoses from compartments and pontoons which
now all came aft from the "S-51" and ran over the "Falcon's" bow to the
manifolds on the bridge.  To tow the "Falcon", an independent 10-inch manila
line was run direct from the "Falcon's" bow past the port side of the
submarine to the stern of the "Sagamore".  The "Falcon" was thus towed by the
"Sagamore" but was able to keep steady and close astern the "S-51" and to
steer the submarine by the stern line to her.

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Figure 20: Stern pontoons breaking surface. 
(Note action of air from pontoons.)

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Figure 21: Stern pontoons breaking surface. 
(Note action of air from pontoons.)

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Figure 22: "S-50" supplying air to "Falcon". 
"S-3" maneuvering alongside "S-50". 
(Note 2-1/2-inch fire hose which carried air to "Falcon".)

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The position of the "Falcon" was rather close to the "S-51"; this was
required, as the "Falcon" was to be ready at all times to supply air to any
compartment or pontoon which showed signs of leakage.  For safety in this
function, the hose leads were kept as short as possible and were so led to
avoid fouling between pontoons.  Even with this close arrangement, the
"Falcon" had 6,000 feet of air hose out to the "S-51".

To avoid running up on the submarine, the "Falcon" did not steam ahead on her
own engines, but permitted herself to be towed by the "Sagamore", and for a
considerable period in the early stages of the tow the "Falcon" kept her
engines going at one-third astern.

The "Vestal" took station about 1,000 yards ahead of the "Iuka", from which
position she navigated for the squadron.  (See fig. 25.)

The position of the pontoons during the tow is shown by Figure 26 and Plate
6.  The stern pair of pontoons was farthest exposed, as was expected.  The
No. 1 and No. 3 pairs of pontoons were floating at about the water line
designed, with slight cockbilling.  The port pontoon of the No. 2 pair was
just awash, while its mate was floating about one-fourth exposed.  This
relation was probably caused by the lashing wires for these two pontoons
binding across the deck of the submarine and preventing the chains from
rendering enough to equalize the submersion.  All pontoons were seen to be
exactly in the fore-and-aft alignment to which they had been set on the
bottom.

The only part of the "S-51" which was clear of the water was her signal bridge
over the conning tower; her No. 3 periscope which showed undamaged about 5
feet above the surface; and the stub of her mast which was exposed the same
amount (the remainder of the mast had been removed as an obstruction during
salvage work).  The top of the periscope shears could be plainly seen about 6
inches below the surface, but nothing else was visible.  From the periscope it
was observed that the "S-51", as slung between the pontoons, was floating with
a steady list to starboard of about 10 degrees.  (See fig. 27.)

From the known lengths of the pontoon chains and the immersion of the pontoons
at bow and stern the draft of the submarine was the same at both ends and was
figured at about 32 feet.  Talking account of the list of the "S-51", this
checked with the draft amidships as indicated by the top of the periscope
shears, which point with the vessel erect was 33 feet above the keel.

This draft allowed a safe margin through all channels encountered and into the
dry dock.  A minimum depth of 35 feet was to be encountered above Hell Gate;
the dry dock was stripped down to give the same clearance.

The first stage of the tow was on a course direct for Point Judith, to get
over shoal water as soon as possible.  An 8-mile run brought the tow to less
than 100 feet depth.  The speed at this time was slow, about 2 knots, later
increased to 3, which brought the tow off Point Judith at dusk.  The pontoons
were riding with an easy undulating motion to a moderately choppy sea on the
port bow, the submarine itself seemed steady, and everything was going well.
There was no evidence of leakage anywhere, but it was decided as a precaution
to keep the air going continuously on all pontoons and on all compartments
with the idea of immediately expelling any water which might leak in before
enough gathered anywhere to cause trouble.

As a further safeguard, the order was given before getting under way to close
all flood valves on the pontoons.  A check made after getting under way showed
that the flood valve on the after end of No. 3 starboard pontoon turned freely
but would not close; also, that as No. 2 port pontoon was awash the boat crew
had not closed the valves on it.

This last condition was felt to be dangerous.  If anything carried away the
two air hoses to this pontoon, the pontoon would be entirely free to flood
(which its awash condition would expedite) and such sinking would cause the
loss of this pair of pontoons and possible disaster in the open sea.

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Figure 23: Bow pontoons breaking surface.

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Figure 24: Preparing tow to New York. 
"Sagamore" in position ahead of "S-51" with "Iuka" at her bow.

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Figure 25: Tow under way-- "Vestal" leading.

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Figure 26: Arrangement of pontoons.

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Figure 27: "S-51" afloat on pontoons. 
(Note top of periscope shears and angle of heel.)

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When the condition of No. 2 port pontoon was reported, the tow was halted for
about an hour and the surfboat sent out to close the flood valves.  The seas
were steadily breaking over this awash pontoon, which made work on it
dangerous.  The boat could not come alongside, but one by one Wickwire, Hawes,
Lieutenant Kelly, and Schissel swam from the surfboat to the pontoon and
finally succeeded in shutting off the flood valves; as an additional
precaution, the blow valves were also closed.

About 9 p.m. the course was changed to west, keeping inside the 10-fathom
curve, and the tow steamed on through the darkness, speed somewhat over 3
knots.  A careful watch was kept on the pontoons, illuminated by the
"Falcon's" searchlights, and the compressors kept a steady stream of air going
to the submarine.

Off Westerly, R.I., near midnight, a strong adverse tide was met and for
nearly an hour the tow made no progress over the ground.  After getting clear
there, progress was smooth and the speed so set as to pass the first danger
point, the Race, at slack water.  Trouble here was especially not desired, as
the deepest water on the journey, about 300 feet in depth, lay in the Race.

The "Vestal's" navigation was accurate, and about 4 a.m. the tow went through
this spot at dead slack water, meeting no currents at all.  When daybreak
came, on July 6, the "S-51" was safely inside the sheltered waters of Long
Island Sound and it was felt that the worst was over.

No further adverse tides of any strength were encountered.  The tow was going
well, and there was not the slightest sign of deeper immersion on any of the
pontoons.  On the contrary, by careful blowing a little more water was
expelled, and the submarine came up a few inches higher.

Under these circumstances there no longer appeared any necessity of following
the devious course along the north shore necessary to keep inside the
10-fathom curve, and a straight course was laid through the sound for
Execution Rocks.

In smooth water, with no swells to cause motion of the pontoons, the "Iuka"
and the "Sagamore" worked up to full power, and the "Falcon" went slow ahead.
The tow soon reached a speed of 5 knots, which was maintained throughout the
morning and part of the afternoon.

By late afternoon it was seen that the tow was marking such unexpected
progress that it would arrive too early at Execution Rocks.  To avoid this
speed was slackened to 2 knots, and for a while the tow steamed in a circle of
about 2 miles radius to lose additional ground.  It did not appear safe to
stop or to anchor, as there was danger that the vessels of the tow would
become tangled up, and especially that the "Falcon" might foul the submarine
or the numerous hoses leading from it.

The navy yard, New York, reported No. 4 dry dock all ready, with 35 feet of
water over the sill and about another foot over the blocks.  The dock had been
stripped down to the bearers to get the maximum draft possible.

A request was made of the yard to furnish a pilot to meet the tow off
Execution Rocks, together with two yard tugs to assist in steering the
"Falcon" if necessary.

Late in the evening the tow ceased circling and resumed its course for the
East River.  Off Hempstead, somewhat after midnight, the two yard tugs joined
the squadron, bringing a civilian pilot from the East River Pilots'
Association; also the navy-yard pilot, who was to handle the tow on entering
the yard basin.

In the early morning of July 7 the most shallow spot to be crossed, about 35
feet deep below Execution Rocks, was passed without stirring up the mud.  The
draft of the "S-51" was between 32 and 33 feet.

Having cleared Execution Rocks, the "Iuka" dropped back until she was
alongside the "Sagamore", and tied up to the "Sagamore's" starboard side, the
desire being to shorten the towing procession as much as possible.  (See fig.
28.)

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Figure 28: Tow approaching Hell Gate. "Iuka" alongside "Sagamore".

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The civilian pilot took station on the "Sagamore" the officer in charge; and
the salvage officer stayed on the "Falcon" as being closer to the "S-51".  The
course expected was down the west side of the river on the Manhattan side,
where 40 to 50 feet of water existed all the way.  As expected, the tow
reached Hell Gate at high water slack and passed through with no difficulty,
everything steering perfectly.  The "S-51" kept a little to starboard of the
line between "Sagamore" and "Falcon", as the "S-51's" rudder was set at hard
right, the position it had when the ship sank.  (See fig. 28.)

The tow now passed down the East River on the top of the morning high tide,
passed to the westward of Blackwells Island, and was practically on its last
mile with the entrance to the navy yard in sight, when it was observed that
instead of following the "Vestal" the "Iuka" and the "Sagamore" were swinging
off strongly to port, talking the "S-51" and the "Falcon" with them.  Before
the meaning or the reason for this unexpected maneuver could be learned there
came sudden bobbing of the pontoons at the bow of the "S-51", the No. 2 pair,
which was nearly awash, floated up completely light, and the "Falcon" found
herself rapidly closing on the stern of the submarine.  (Fig. 29.)

With but a few seconds available for action before ramming the "S-51", the
"Falcon" went full speed astern and put her rudder hard left.  She just
cleared the "S-51's" port quarter and reduced the collision to a minor impact
with the No. 3 port pontoon abreast the conning tower.  Here the "Falcon"
stopped, having missed the important buoyant stern compartments and having
avoided carrying away all the blowing hoses.

The "Falcon" and the "S-51", which had been headed downstream, now started to
swing to an ebbing tide and in a minute or two came to rest headed nearly
upstream.

Meanwhile the "Iuka" and "Sagamore" had stopped, the towline to the submarine
having come slack and the preventer towline to the submarine together with the
line to the "Falcon" having been cut in the emergency by the "Sagamore".

The cause of this occurrence was not at first grasped by the salvage
officers.  Knowing that a deep, broad channel existed for the pilot to follow,
it did not occur to them than the "S-51" had grounded.  Wild as the idea
seemed, and with no reason for believing it probable, it was thought at first
that the "S-51" had broken in two forward, thus releasing the No. 2 pair of
pontoons and stopping the tow.  But a hasty examination from the surfboat
showed the submarine intact; in spite of having swung nearly 180 degrees since
grounding, the three pairs of pontoons still left lined up in a perfectly
straight line which was impossible with the submarine in two pieces.

The next surmise was that "S-51" had hit a submerged wreck; this was being
checked by soundings, when a fix obtained on the "Falcon's" bridge and plotted
on the chart disclosed that the pilot had left the main channel to try to pass
through a narrow side channel between two reefs, had misjudged his distances
and the tide, and had run the "S-51" aground on Man-of-War Rock at practically
the top of the high tide.  The bow of the "S-51" was found to be in a little
over 24 feet of water.

The tide had now turned and was starting to run a strong ebb.  The two freed
pontoons were tugging on their hose lines and were foul of the hoses to the
No. 1 pair.  The surfboat crew cast loose the hoses on the No. 2 pair and
cleared the other hoses, the "Iuka" towed the two pontoons to the near-by navy
yard, where the chains were found to have parted under the submarine, cut in
half on the reef.

The air was kept going on all compartments and the remaining pontoons - so far
as could be seen the interior compartments were still undamaged and buoyant
and the six pontoons left seemed firmly attached.

A hasty estimate was made of the situation.  Up to the moment of grounding,
the No. 2 pair of pontoons showed by their immersion that they were exerting a
net lift of about 120 tons, which was now lost.  A check on the previous
reserve buoyancy of the No. 1 pair and the No. 3

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Figure 29: At the instant of grounding on man-of-war rock. 
(Note No. 2 pair of pontoons rising and drifting to starboard.)

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Figure 30: "S-51" on man-of-war rock. 
Clearing hoses in preparation of lowering pontoons.

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pair showed a reserve in those two pairs of slightly more than this.  If this
reserve could be brought into action it would overbalance the lost buoyancy
and would maintain at least as high a forward moment, as the No. 2 pair had
been located exactly between the No. 1 and No. 3 pairs.  (See fig. 30.)

To obtain this reserve, it was required that the four remaining forward
pontoons be resecured just awash; if they could in addition be secured any
lower than that, the bow might be lifted higher than ever to assist in
floating it clear.

To carry out this plan, the yard was ordered to send out a 75-ton derrick with
additional tugs and a rigging gang.  Also, in case diving was necessary, the
yard diving launch was sent for.

In case it turned out that extensive wrecking operations were necessary (it
was estimated that two weeks might be required), the "Falcon" could not
continue to hang on to the "S-51" as an anchor, and something was required to
hold her in the tide.  All her own moorings being still off Block Island, the
Army engineer who had charge of East River dredging (and who had come aboard)
very kindly provided two heavy anchors, chains, and buoys, which were given to
one of the light yard derricks for planting up and down stream.  The Army
representatives also carefully plotted the position of the "S-51" with
reference to their known soundings on Man-of-War Reef.  These showed rocks
upstream, on the Brooklyn side, and downstream.  The bow of the "S-51" was
pocketed, with clear water only on the side toward Manhattan.

Meanwhile the tide was running out strongly, certainly over 5 knots at that
point, and it was plain that no diving was ever going to be possible there
except for brief periods at slack water.

As the tide dropped, the No. 1 pair of pontoons floated higher and higher
above the water, until they were taking very little load; to a lesser extent
this was noted on the No. 3 pair; the stern pair floated unchanged.  The reef
forward was talking the weight off the bow pontoons, and as the tide dropped
the "S-51" heeled more and more to starboard until it lay over at least 20
degrees.

The diving launch arrived first.  It was moored over the location of the lost
pair of pontoons with the intention of examining the damage to the ship and
the exact position of the "S-51" with reference to the reef; it was further
intended to run new reeving lines under here in case it was possible to get
them by the rocks.  This last was for the purpose of running a new set of
chains and resecuring the missing pontoons if that proved necessary to lift
the bow clear.

About this time the first derrick, of 25-ton capacity, arrived from the navy
yard.  The tide had dropped over 3 feet and the bow pontoons were well out of
water, neither one of them was taking as much as a 25-ton strain.  The derrick
was brought by two tugs, headed somewhat across the current against the No. 1
starboard pontoon, and held there by the tugs.

By slacking away the boom, it was able nearly to plumb the port No. 1
pontoon.  A pair of wire slings, suspended from the boom, were shackled to the
ends of the chains showing through the port pontoon hawse pipes.  The derrick
then took its maximum strain, the flood valves on the port pontoon were
opened, and the air was vented from the pontoon to sink it.  Very shortly the
toggle bars on the hawse pipes came slack in the chains and were withdrawn.
The pontoon was flooded down until it was awash, when the studs were burned
out of the links in the chain just above the hawse pipes, the toggle bars were
inserted in the new locations and the locking pins put back.  A slight amount
of air was blown into the pontoon until it came up hard against the toggle
bars, when the derrick slacked away and cast loose the slings which were
immediately secured to the chains on the starboard No. 1 pontoon.  (See fig.
31.)

Low-water slack came at this point in the early afternoon.  The divers
prepared to go down when the tide turned and the "Falcon", "S-51", and the
derrick all started to swing upstream to the

      45129-27--6

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Figure 31: 25-ton derrick taking maximum strain on chains 
of port pontoon. Pontoon below surface and diving boat 
in position for inspection of bottom.

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flood tide, with everything pivoting about the bow of the "S-51" as the center
of rotation.  The "S-51" came to rest, headed generally downstream, but about
45 degrees with the direction of the main channel.

Two divers now went down for an examination.  They found that from about frame
50 aft, the "S-51" was entirely clear of the reef; that she was resting on a
shelf under her keel from this point for some distance forward, and that on
her port side she was resting against a huge bowlder about 8 feet higher than
the keel, which was apparently what was preventing a complete swing upstream.
The "S-51" was lying well over on her starboard side, with her bilge keel on
the rocks.

The divers thought it possible to get reeving lines under and an attempt was
made.  Using a 6-foot pine plank about 4 inches wide as a batten, with a
21-thread manila reeving line attached to it, the diver (Eadie) shoved it
under the keel to upstream side, the idea being that the flood tide, which was
now running strong, would carry the batten through.  Eadie fed through over
100 feet of line which the current took, but so powerful was the tide that the
line was apparently carried out straight beneath the surface and the batten
did not show.  By using a grappling hook from the surfboat and dragging on the
upstream side, the line was soon hooked and the batten brought up.  One
reeving line was thus rendered through and the ends secured to the No. 3 pair
of pontoons, but the current was now so strong that no more divers could work
and no attempt was made to run the second reeving line then.  The outside
diving time appeared to be 40 minutes while the tide was turning; even the
latter part of this period, the current was so swift that Eadie reported that
to get to the bottom he had to haul himself down the descending line.

While the divers were working on the reeving line the derrick was holding up
the chains to the starboard No. 1 pontoon, and this pontoon was flooded down
for resecuring.  A great deal of trouble was encountered here, for the tide,
acting on the derrick and the pontoon, carried the pontoon over the top of the
submarine, where it rested on the deck and would not sink far enough.
Finally, with three tugs on the derrick steaming full speed against the
current, the pontoon was dragged off clear to the starboard side, where it was
sunk until it was awash and the toggle bars resecured.

As both of the pontoons of the bow pair had been sunk at low tide, there was
gained at this point not only all the reserve buoyancy of the No. 1 pair, but
also an added lift to reduce the draft at the bow, which was practically equal
to the tidal range - about 4 feet.

The derrick now let go the slings to the starboard bow pontoon and endeavored
to get clear; the three tugs had a struggle, as the tide swung them into the
other pontoons, and managed just to drag the derrick clear, but at the expense
of an 8-inch line from the "Falcon" to a downstream tug, which line had
hastily to be cut to let the derrick pass astern.

It was now mid-afternoon and the tide was coming up.  The 25-ton derrick had
only barely been able to handle the chains on the light bow pontoons; for the
midship pair it was inadequate and was sent away to anchor.

The tugs brought the much heavier 75-ton derrick into position against the
port side amidships, where they held it stemming the tide, with the port No. 3
pontoon under its bow.  Here the chains from the port pontoon were secured to
the boom of the derrick, using a 1.5-inch wire pennant on each chain.  The
derrick now took a strain, estimated at about 50 tons, which caused the toggle
bars to come slack shortly after flooding commenced.

As this pair of pontoons happened to be the ex-"F-4" pair of 80-ton pontoons,
with smaller flooding and venting valves than the pontoons built at New York,
flooding was much slower.  As the day was passing and the tide rising,
expedition was essential.  To facilitate flooding, the 0.75-inch vent and
flood valves on top were unscrewed to permit the air to escape faster.  The
pontoon was at this period about 3 feet out of water, with the toggle bars
still in the chains but

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several feet above the tops of the hawse pipes.  It was intended to put the
valves back when only about 1 foot of the pontoon showed above the surface.

Three people were on the pontoon under the overhang of the derrick's bow, the
salvage officer and two members of the "Falcon's" crew, Badders and Schissel.

At this instant, without warning and, so far as could be seen, without reason,
the wire slings both parted, the released chains came down, bringing the
toggle bars with a crash on top of the hawse pipes of the pontoon, which
promptly submerged and disappeared under the bow of the derrick; the bow of
the derrick, with its strain suddenly released, jumped several feet in the
air, and the starboard No. 3 pontoon floated up entirely light.  Relieved of
this support against the starboard side of the conning tower, the submarine,
which was already badly listed to starboard, now rolled farther so that the
periscope and all parts of the signal bridge, which had before been visible,
disappeared completely from view.  The submarine was thought to have rolled
over completely.  With the support of the No. 3 pair of pontoons now gone, an
added load was thrown on the stern pair of pontoons, which sank about 4 feet
deeper in the water.  Fortunately reserve in this pair of pontoons was large,
and this added load did not wholly submerge them; if it had, the stern of the
submarine would, of course, then have gone to the bottom and the wrecking
operation would have become more complicated.

The three men on the pontoon found themselves partly submerged; the pontoon
came to a stop about 3 to 4 feet under water, and then the forward end of it
floated up until it was about 1 foot clear of the surface; the after end
stayed submerged and the water covered the pontoon nearly to the forward hawse
pipe.  A brief glance showed that the toggle bar in the forward hawse pipe was
gone and there was no chain in sight in it (the derrick crew claimed this
toggle bar broke in half under the impact).  The pontoon was in a precarious
position, with its four top valves removed and three of the holes submerged;
it was free to fill and sink (it had no great amount of buoyancy left then
anyway) and if it did without having two chains secured to it and with no
valves or air hoses attached, it was questionable what could be done to it by
divers in that tide.  Action was taken instinctively - the three men on the
pontoon promptly shoved their thumbs into the three submerged vent-valve
openings to prevent the escape of air and stop further flooding, and the
derrick crew were ordered to make some 0.75-inch wood plugs immediately.  The
man plugging the hole at the low end could barely keep his face above water;
the other two were better fixed.  The first wood plug was driven into the low
end hole by Schissel, who stayed under water a considerable period to
accomplish it; the two middle holes were easily sealed temporarily and then
the valves were resecured to them and the air hoses coupled up.

The pontoon was now inspected.  The after end chain appeared all right, with
its toggle bar resting across the hawse pipe; the forward end hawse pipe was
just out of water, the toggle bar was missing, and the end of the chain could
be felt about 4 feet down the hawse pipe, where it was hanging on two parts of
a 6-inch manila line which had fortunately been secured as a preventer to the
end of the chain when the derrick took its first strain.  (It was an
invariable rule of the salvage operation from the beginning to put a preventer
line on everything wherever it was possible.)

The preventer line was cautiously tested and it was found that only the weight
of the chain itself was on it (the chain was slack under the submarine).  It
was carefully worked up until the eye of the 1.5-inch wire came out (the wire
had parted just above the eye splice), when a heavier line was secured to the
eye.  The chain was then worked up on these lines until it showed above the
hawse pipe, when a new toggle bar was inserted in it and secured, which
occasioned considerable relief.

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The mate pontoon was now flooded down until the port pontoon floated just
awash, when all valves were properly replaced.  The port pontoon was then in
satisfactory awash position, and work was started to sink its mate, the
starboard No. 3.

An inspection between the pontoons showed that the position of the submarine
was not as bad as had first appeared when the slings let go.  The remains of
the periscope could still be seen a foot under water, its angle indicated that
the ship was lying over from 30 degrees to 40 degrees to starboard.

Using a new pair of 1.5-inch wire pennants, doubled this time, though there
was now practically no strain on the chains, the derrick took a lift on the
chains and held them while the starboard pontoon was sunk.  As an added
precaution, an extra toggle bar was secured, and as the chain links came clear
of the hawse pipes one at a time, the studs were burned out and a new toggle
inserted before the existing toggle was removed; in this way a toggle bar was
kept close to the hawse pipe at all times while the pontoon sank.

The pontoon had to be kept well to starboard to clear the bridge as it went
down.  This was possible, as high-water slack was approaching and the current
was easing off.

The resecuring of the starboard No. 3 pontoon was finished as darkness came
on, and the derrick was taken away.  The bow pair of pontoons had for some
time completely disappeared below the rising tide (fig. 32); the middle pair
of pontoons was also completely covered as the tide reached its maximum.

Preparations were now rapidly made for attempting to get free.  The "Sagamore"
was anchored on the Manhattan side of the river and a line run to her from the
"Falcon"; the wreck was starting to swing and was lying then practically
athwart the stream; it would have swung downstream if not for this support.

The "Falcon" was astern of the "S-51", headed in the same direction (toward
the Brooklyn side) with only the original stern line secured to her, this line
leading over the "Falcon's" bow.  It consisted of a 1.5-inch chain bridle
completely encircling the "S-51's" stern inboard of the shafts, with 150 feet
of 1.375-inch wire shackled to the bridle and lead to the "Falcon", where the
end was secured.

Both bow lines to the submarine had either been cut or carried away on first
grounding.

The "Iuka" was secured to the "Falcon's" starboard side, headed opposite to
her and two yard tugs were secured to the "Falcon's" port side, also heading
in the opposite direction.

At 9.30 p.m., everything was secured, the tide was up, and had started to
ebb.  All vessels were ordered to stand by, and the air was turned on the
pontoons.  As the pressure required was low, compared to that needed off Block
Island, this operation was much more rapid.

In a few minutes the stern pair of pontoons (which were not being blown)
started to rise farther out of water, and very shortly the No. 3 pair showed
slightly above water and then vented all around, showing themselves dry.  All
air and the searchlights were turned on the bow pair; these soon vented all
around and then rose until the starboard bow pontoon barely showed above
water; the port bow pontoon, although dry, remained completely covered.

All indications were that the bow had been lifted at least 4 feet and was off
the rocks.

On signal the "Sagamore" heaved on her line, the "Falcon" went astern on her
engine, the other tugs started ahead, and the wreck moved with no apparent
strain.

The line to the "Sagamore" was let go, and, guided by the other tugs, the tow
started downstream after getting well over to the Manhattan side; the "Falcon"
and the "S-51" were now towing stern first, but the other vessels were headed
in the direction of motion.  The "Sagamore" up anchored and took station ahead
with a line to the "Falcon's" stern.

By now the current was strongly ebbing; the make-up of the tow was not wholly
ideal.  The "S-51" was going backward, drawn by the line to the "Falcon", but
there was no line on the

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Figure 32: Bow pontoons below the surface at man-of-war rock.
 Crew opening valves.

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submarine's bow nor any vessel there to guide that end and hold it in
position.  The general situation at Man-of-War Rock and the lack of time
prevented any other arrangement; the tow had to be taken as it was.

Below the Williamsburg Bridge the tow worked over to the Brooklyn side and
made a turn to the left to enter the navy-yard basin.  Here the strong tide
caught the "S-51" and "Falcon" broadside and swung them downstream; to avoid
fouling her propeller the "Falcon" had to cut loose the line to the
"Sagamore".

The current swept the tow downstream below the navy yard, swinging it around
meanwhile, and by the time the tow had stopped swinging and was once more
headed toward the yard it was half a mile below the yard and losing ground
against the tide.

At this stage the "Falcon" was going full speed astern and the three other
tugs full speed ahead; in spite of this the whole tow was still gradually
drifting down the river, and the solitary line to the "S-51" was under a
terrific strain.  The reserve buoyancy of the "S-51" was now negligible; if the
towline parted, the air hoses would all be carried away and the submarine
would sink in a very few minutes much before anything could be done.

Fortunately, while intended only for a stern guide line, the possibility of
having to tow by it had been kept in mind when the stern line was designed; it
was adequate to the occasion and had been well secured by the divers while on
the bottom off Block Island.

Now for an hour it took the full strain of four heaving vessels while they
battled to hold their own against the tide; the "Sagamore" at last got another
line to the "Falcon's" stern and threw her power into the struggle; the
drifting stopped and almost by inches the tow moved up the river and finally
fought its way into the quiet waters of the navy-yard basin.  Here the "S-51"
was tied to one of the piers, the "Falcon" close by, pumping air continuously.

The reserve buoyancy forward, about 180 tons on leaving Block Island, was now
less than 14 tons, the submarine was rolled far over to starboard, her bow had
been torn off by the towline shackled into it when she suddenly stopped on
hitting the rocks, and the light bridge structure had been smashed by the
heavy roll to starboard against the starboard No. 3 pontoon.

It was 11 p.m. when the "S-51" at last came into the yard, and it was the
earnest desire of the salvage crew to run her into the dry dock before
anything more happened, but the docking crew had long since been dismissed, as
no hope was felt in the yard that the "S-51" could be brought in in the near
future.  Even then the salvage crew would have docked the ship themselves, but
the tide had dropped so far since high water at 9 p.m. that with her 33-foot
draft aft the "S-51" was hardly likely to drag across the sill.

Nothing could be done except to keep on pumping air through the night and wait
for the next high tide.

The morning of July 8 the submarine was found in the same condition as the
night before, barely afloat forward.  The starboard list was not quite as bad
as when last seen on the reef, for the starboard No. 3 pontoon was again
bearing against the conning tower and had reduced the list to between 20
degrees and 30 degrees.

The submarine was swung and headed for the dry-dock entrance.  A number of air
lines were prepared on the dock to couple up in place of the "Falcon's" hoses,
and when all was ready the "Falcon" closed off all blowing hoses, passed them
over to the top of the stern pair of pontoons, and let go the stern towline.
(See fig. 33.)

With about 35 feet of water over the sill, the "S-51", drawing 33 feet aft and
less forward, was hauled into the dock and pulled over the center of the dock
without trouble.  All dock air lines were coupled up and blowing started again;
it was observed that the bow had gone down a few inches while the air
connections were broken.  (See figs. 34 and 35.)