I?eed, Edward J.
Letter ... on ship railways and canals

nc<i-.u

- iLHM&&iEir •

LETTER

Sir Edward J. Reed, K. C. B.

Rear Admiral Ammen, U. S. N.

Ship Railways and Canals

AMERICAN ISTHMUS.

SHIP RAILWAYS AND CANALS;
By Sir Edward J. Reed, K. C. B. , in Reply to a Letter Addressed
to Him by Rear- Admiral Daniel Ammen, U. S. N.

[jSSfr Edward Reed is a member of Parliament, and was for many years
Chief Constructor of the British navy. He was made a Knight Commander
of the Bath, as a recognition of his eminent abilities as a naval architect.
He is a Fellow of the Royal Society; Member of the Institution of Civil
Engineers, and of the Institution of Mechanical Engineers, and is Vice-
President of the Institution of Naval Architects. He has written several
treatises on ship-building, and is, without doubt, the highest authority in the
world to-day on this subject.]
Broadway Chambers, Westminster, London,
September, 1881.
To Rear- Admiral Ammen, U. S. N.
Dear Sir: — In a former letter I explained to you that illness,
&c, prevented me from replying promptly to your esteemed favour
of March 15th, and I regret to say that the same causes have
operated until the present time. I will now endeavour to reply
with sufficient fullness to your inquiry, first thanking you for the
copies which you have so kindly sent me of papers by yourself, by
Mr. Menocal and by Capt. Phelps, all of wliich I have read with
interest and profit. Your own paper and that of Mr. Menocal
are full of the most instructive and valuable information upon the
various Canal projects, but naturally have little or no direct bear
ing upon the Ship Railway proposal. In discussing that I must
therefore direct my attention to the pamphlets by Capt. Phelps
which are specifically addressed to it.
The suggestion to transport ships loaded with cargo from one
ocean to another over a railway more than 100 miles long
is one which was certain at first to excite many doubts and
suspicions, both among those who do, and among those who do
not, understand the construction of ships and railways.

— 2 —
But first impressions upon a matter of this kind are of little
value, and all such, whether favourable or otherwise, may be dis
missed from consideration. Let us investigate the matter closely,
and in the light of existing knowledge and experience.
And in the first place I feel obliged to express surprise at the
contention of Capt. Phelps that the ship-railway across the
Isthmus of Tehuantepec must be adapted for transporting ' ' the
heaviest vessels used anywhere." On the contrary, the primary
requirement clearly is, that the railway should be adapted to carry
the vessels engaged in ordinary commerce, and more particularly
such as are employed in distributing to the world the corn and
other products of California and the neighbouring States. To
Americans, the quick and economical interchange of products be
tween the Eastern and Western States, by means of their own
mercantile vessels, would, I think, be the primary objeot to attain ;
for this purpose it would certainly not be necessary to provide for
the transport of such ships as the " City of Rome," the " Servia,"
and other immense vessels now building in this country expressly
and solely for improving the intercourse between America and
Europe. . On the contrary, I should anticipate that a ship-railway
sicross the Isthmus of Tehuantepec, which would reduce the sea
communication between the East and West of the United States
to the utmost possible extent, would be a great stimulant to the
employment of American built vessels, of wood as well as of iron ;
and in so far as the wood-built sailing vessels are concerned,
it is obvious that the demand for immense size would not arise.
Looking to the still available resources of the United States in
ship-building timber, I can understand that the ship-railway would
be a very great encouragement to the continued building of this
class of ships in Maine and other States. There is undoubtedly a
general tendency to increase the size of iron-built steamers in
many trades, and this will certainly have to be taken into account
in determining the character both of the railroad and of the ter
minal works, but after much consideration of the subject I have
satisfied myself that no present necessity exists, or is in view, for
proceeding with the ship-railway upon a scale so large as to ac
commodate the heaviest and longest of the passenger liners now
in course of construction. The trade of, the world, and assur
edly the American trade, would be amply provided for if pro-

vision is made for transporting ships of a maximum displacement
of 6,000 tons. But even 6,000 tons displacement is a limit higher
than would be needed to accommodate the vast majority of the
world's merchant- vessels at present, and would provide for a large
and pretty general increase in their size hereafter. I will add but
two remarks in this connection : ( 1. ) It might be wise, and would
certainly be easy, to ensure the commercial success of the ship-
railway across Tehuantepec by carrying, in the first instance, ves
sels of say 4,000 tons at most, making due provision for the sub
sequent increase of size and weight in such a manner as to avoid
interference with the operation of the line. (2.) One of the ad
vantages which the railway project possesses is that, if suitably
designed, its capability of transport, both as to the size and as to
the number of vessels transported, can be increased with facility
and economy.
You will see from what I have aheady said that I am unable to
accept the view of Capt. Phelps with respect to the weight of the
ships to be carried. I regret to say that I am equaUy unable to
accept his statement of the auxiliary weights to be carried, viz.,
those of the ship car and cradle. These Capt. Phelps regards as
about equal to the weight of the ship and cargo. I am of
opinion — after making some guiding calculations — that the
weight of a car and cradle^ of ample strength to carry a ship of
4,000 tons weight, need not exceed 500 tons ; if to carry a ship
of 6,000 tons it need not exceed 750 tons. The aggregate weight
¦to moved, therefore should be : —
For a ship weighing, with cargo, 4,000 tons, - 4,500 tons.
" " " 6,000 " 6,750 "
I therefore regard his estimate as enormously excessive.
I will next consider the mode of raising and transporting the
ships. And I would state that although there would be great and
obvious conveniences in keeping the ship always afloat during the
transit, I am of opinion that this would involve much unnecessary
expense, both in the construction and in the working, and that no
sufficient reason exists for pursuing this plan. In so far as the
lifting of the ship bodily out of the water is concerned, this pro
cess is in repeated operation at the Victoria Docks on the Thames,
at Malta, at Bombay, at Sebastopol, and elsewhere; while the

— 4 —
process of hauling ships up out of the water upon a wheeled car
riage on an inchned plane laid with rails is, as you know, a very
common one. I had two such hauling-up slips under my con
trol for some time at Hull, and the company working them have
found them so convenient and profitable that, they are now laying
down a third for hauling up ships of 3,000 tons register and
more. No engineer can doubt that either process is perfectly
applicable, with increased power, to ships of larger size, although
I should myself prefer the process of direct lifting, for several
reasons, the chief of which is that it furnishes the readiest and
best opportunities for supporting the ship upon the cradle as she
leaves the water.
This brings me, of course, to the crucial questions: 1. Can
ships with their cargoes on board be lifted out of the water, by
hydraulic lifts or otherwise, and upon adjustable cradles, without
injury? 2. If this is so, can they be with safety transported over
land upon such cradles ? I answer both questions affirmatively,
and for the following reasons : I would lay down as a first con
sideration that in both cases the chief cause of injury to be
guarded against is not general structural strain, but local strain
resulting from unequal distribution of weights,' and more especially
of cargo. I may perhaps be excused for speaking with some con
fidence upon this question, inasmuch as it was in a paper read by
me before our Royal Society in 1871 , and published in extenso
by that learned body, that the principles of strain in ships
and the method of estimating the strains, now universally ac
cepted were first laid down. I affirm that the general struc
tural strains which are likely to be brought upon a ship
j by lifting and transporting her, presuming, of course, that reason-
I able skill and care are applied to these processes, are inferior, much
f inferior, to those strains to which every ocean-going ship is con-
| tinually liable at sea. Indeed the only structural strain which
would require to be very specially guarded against, is that which
exhibits itself in, and in connection with the beam-knees of wooden
ships ;* and even this, with proper bilge support, would be less
than the like strain which occurs at sea. The strains to be most
* Perhaps I Ought to mention that all my early experience as a ship.
builder, extending over some eight or ten years, was acquired in the con-,
struction and repair of wooden-built shipa. — E. J. E.

apprehended, and against which it would be necessary to make
effectual and ample provision, are local strains, and chiefly those
arising from heavy cargo pressing severely upon parts of the bot
tom, and often alternating with places of much less weight, or of
none at all. But I apprehend that an engineer of the ekill and
eminence of Capt. Eads, with all the experience of ship-builders
at his command, would not undertake the work of lifting and
transporting loaded ships without making full provision, as may
be readily done, for applying ample local support to every ship's
bilge at every part ; nor would the company who construct and
operate a ship-railway, and who are responsible for the ship, be
hkely to fail to have the support carefully applied in every case
where needed. In fact, it would be made, I should think, a ruling
consideration in this enterprise to so bring the great resources of
hydraulic art into play, as to give to each ship that is lifted, far
better support than has ever before been provided in any docking
system whatever. To accomplish this object effectually would
certainly be a problem of much easier solution than many which
Capt. Eads and other engineers have solved with perfect satisfac
tion, both in yoUr country and in ours. Nor are we without ex
perience to guide us- in this matter. The hydraulic lift at Malta
has raised numerous ships, with cargo on board, without the
slightest injury of any description. From a hst of such vessels
furnished me by Mr. Webb, the Secretary of the Anglo-Maltese
Hydraulic Dock Company, Limited, I find that ships carrying heavy
cargoes have been frequently raised high and dry in this way with
out detriment.
In the next place, it seems to me quite certain that the appli
ances which would secure ample' and firm support to the ship, at
every part, when lifted high and dry, would almost necessarily be
such as would effectually keep her upright in storms, and preserve
her from any injury upon the road. I take for granted that the
railroad constructed for the purpose would be of the most solid
kind, and so laid as to have its double or triple sets of rails as
nearly as possible in the same plane, and also that the carriages
would be made with equal care in all their parts. With these pre
cautions taken, and considering that a comparatively low speed is
all that is required or contemplated, I am at a loss to see in what
way danger to the ship is to arise. I will only add upon this part

of the subject, that I see no sort of necessity for having a special
cradle fltted to each ship, in any other sense than that of taking
care to give support to each ship, wherever necessary by hy
draulics or otherwise.
There are some observations of Capt. Phelps which I am at a
loss to understand. I do not, for example, know what he means
by saying that the pressure of the water upon the bottom of a
floating ship exerts " equal force upon every inch of its surface ; "
or by saying, ' ' whether rolling or pitching, the support from the
water is uniform at all times and at all points ; " or by adding,
"when waves toss the ship about it becomes a falling body re
ceived upon a water cushion, so to speak, which presses and yields
everywhere in exactly the same degree ; hence there is httle or no
strain in a well-constructed ship when the weight carried is evenly
distributed, as seamen take care it shall be." With all respect I
must say that these statements are in conflict with both the most
elementary and most developed doctrines of science, which declare
that the still water-pressures upon a ship afloat vary with and as
the depth ; that they are consequently different in amount at dif
ferent depths ; and that when a ship is tossed by the waves she is
thereby subjected to great, and sometimes to enormous strains,
and that these strains undergo continual fluctuations. In the
Royal Society paper which I have previously adverted to, I have
shown that even the light wood-built yacht of Her Majesty the
Queen, the "Victoria and Albert," when hfted upon the
crest of a wave of her own length (300 feet) and 20 feet high
from hollow to crest, has her bending moment tending to produce
"hogging" (which moment in still water is 5,080 foot tons)*
increased to 16,400 tons, while in the hollow of similar waves the
hogging moment disappears, and is replaced by a reverse or " sag
ging" moment of no less than 31,000 foot tons. In the passage
of a single such half-wave under her, therefore, i.e., in less than
four seconds, this lightly built vessel may at any time be subjected
at sea to a change of breaking strain at a given section of no less
than 47,400 foot tons. Forgive me if I here quote a few sen-
* Foot tons, in this sense, measure leverage which constitutes the
straining or bending moment. Thus, 5,080 foot tons means a weight of
5,080 tons acting at the end of a lever 1 foot long, or 508 tons at the end
Of alever io feet long, or any equivalent leverage.

tences bearing upon this matter - from the paper referred to : "I
give these figures merely as indications of what may be expected
to happen in the changes of strain in ships at sea ; and they prob
ably fall much below the truth, since no account has been taken
of- the effect of violent pitching motions, which must lead to still
more abrupt and violent changes. I will simply add that a very
convenient way of expressing the effect I have been attempting to
describe, is afforded by the supposition that the ship is fixed, and
that what may be termed ' waves of strain ' roll through her struc
ture. The introduction of this idea will help us to understand
more clearly how changes in strain affect a structure ; for a very
small strain (considered statically), which would not affect a com
paratively weak structure sensibly if it were constantly acting in
one direction, will suffice to destroy a far stronger structure if its
direction is continually and rapidly changed. This subject has
not escaped the attention of preceding writers ; and Mr. Fair
bairn has made some interesting remarks upon it, at page 13
of his work on ' Iron Ship-building,' where he refers to the re
sults of a series of experiments on the endurance of iron
jointed beams when subjected to changes in the loads put
upon them. He says the joints of an iron-rivetted beam
sustained upwards of three million changes of one-fourth the
weight that would break it, without any apparent injury to its
ultimate powers of resistance. It broke, however, with 313,000
additional changes when loaded to one-third the breaking weight,
evidently showing that the construction is not safe when tested
with alternate changes of a load equivalent to one-third the weight
that would break it." You will see, therefore, that it is quite im
possible to assent for a moment to Capt. Phelps' opinion that a
well-constructed ship undergoes " httle or no strain " when waves
toss the ship about. On the contrary, a ship tossed about at sea
undergoes enormous strains and changes of strain, the rapid re
currence of wliich adds greatly to their power of injury. It may
serve, perhaps, to give greater definiteness to the matter if I say
that while, as I have stated, the change of breaking strain caused
by waves may, in the case of the royal yacht in question, readily
exceed 47,400 foot tons, the whole breaking strain amidships if
she were left high and dry upon two rocks, one at the bow and the
other at the stern, would only be 114,700 foot tons ; so that the

breaking effect of waves passing smoothly along her amounts to
t'rjj which is nearly one-half the greatest breaking strain that
she could possibly undergo if accident left her to ground upon a
rocky coast, under the very worst conditions. I therefore differ
altogether from Capt. Phelps, believing that he greatly overrates
the strains to which ships properly docked and transported would
be subjected, and as greatly underrates the strains to which they
are undoubtedly subjected at sea.
If I may now turn to the non-nautical parts of the pamphlets by
Capt. Phelps, I would say that it really appears to me that the
difficulties which he apprehends concerning gradients, turn-tables,
tilting-tables, sidings, and locomotives requisite for a ship-railway
are mainly, and in so far as they profess to be insuperable, wholly
imaginary. I will not discuss them at any length, but will trouble
you with only one or two remarks upon them. Capt. Phelps' esti
mates that 60 locomotives would be required for use upon a gra
dient of 40 feet per mile. Now, in a paper recently read before
the British Association at York, Sir F. J. Bramwell, one of the
very ablest engineering experts in this country (who, by the way,
said at the same place, that ' ' ships upon a railway would not be
exposed to half the rack and strain that they are now exposed to
on the ocean " ) , stated that at slow speed good engines would draw
800 tons. They can in fact draw more, but let us accept these
figures. Sixty engines would therefore draw 48,000 tons, or 7
times the maximum weight which, as I estimate, it is at present
requisite to provide for. Instead of 60 locomotives, therefore, 9
or 10 locomotives of the ordinary type would suffice, and proba
bly 5 or 6 would be sufficient' for the large majority of the ships
to be transported, extra power being, of course, applied over the
short distance where the gradients are exceptional. Again, Capt.
Phelps give 5 tons pressure per wheel as the limit which may be
properly applied ; but this is only about one-half of the pressure
which is sometimes allowed for the wheels of our fast-running
locomotives. Instead of 4,800 wheels being required, as he esti
mates, I should think that the 800 (without the 4,000), would be
ample for the largest carriages to be employed on the railway.
In the pamphlet entitled, "Review of the Proposed Tehuantepec
Ship Railway," Capt. Phelps tabijlates all the largest ships in ex
istence and in course of construction, both mercantile and war

vessels, and correctly shows that both descriptions have obtained,
in exceptional instances, displacements of about i3,500 tons. I
cannot myself accept the arguments with which he follows these
tables, nor does it appear to me to be necessary to do so ; for while
I should consider it advisable to make an Isthmus Canal, once for
all, of sufficient capacity to give passage to the very largest ships
that can be found, I should deem it perfectly unnecessary to give
a ship-railway equal capacity in the flrst instance, because the
railroad accommodation is itself so susceptible of extension at any
time. To illustrate this, let me point out the fact, employing the
table of Capt. Phelps, that although the " Tokio " may have a
displacement of 9,000 tons, and the " City of Rome " is to have
a displacement of 13,500, the two vessels differ in breadth by
only 4£ feet, but differ in length by 123 feet. It is manifest at
once that4he principal change required in passing from the smaller
to the larger ship would be that of providing a carriage or cradle
100 or 120 feet longer. But the fallacy of arraying the largest
ships that can anywhere be found against a plain business proposal
like that of the Isthmus Ship Railway, may perhaps be best seen
by observing that, as Capt. Phelps shows, while the very largest
of the mercantile ships, the "City of Rome," is only 52£ feet
broad, the war-ship "Inflexible" is 75 feet in breadth; so that
it' Would appear to be the view of Capt. Phelps that it would be
improper to construct a ship-railway at Tehuantepec for commer
cial purposes, even if it were capable of transporting the largest
mercantile ships in the world, unless you added 50 per cent td
the width and cost of the permanent way necessary for them, so
as to accommodate the biggest ironj-clad that England has ever
produced ! It only needs to state the case thus in order to show
the fallacy of the contention, and to indicate, as I think, that
it is not by considering the cases of the very largest ships that
can be found in the world that the project of Capt. Eads ought
to be tested. I beheve that even if this were a legitimate test the
scheme would not be found to fail in a scientific sense ; but
clearly both the commercial value of the ship-railway, and its
value to the United States as a nation, are entirely independent of
these exceptional cases, and must mainly be judged of by the
measure of facility which its adoption would afford to the general

— 10 —
commerce of the world, and to the mercantile marine of the
United States in particular.
I do not think I need add to these observations, which have
occurred to me on reading the pamphlets of Capt. Phelps. But
in your letter to me you make specific mention of a proposal said
to have been made by Capt. Eads, to allow the ends of vessels to
project, if necessary, beyond the supporting cradle by 50 or 60
feet. I do not understand Capt. Eads to have made any general
proposal of this kind, and I feel confident that he would confine
any such proposal to the case of iron ships ; it certainly would not
be safe to allow such overhang in wooden vessels, but in iron ves
sels of large size it would, as a rule, do no harm whatever. It
will follow from what I have previously said, that the bending
moments due to such unsupported ends would be very small in
comparison with the bending moments induced by the straining
action of ocean waves. Of course it is possible that when the
ship was in motion along the railway, a considerable amount of
lateral vibration might be set up ; but I am at a loss to understand
how either the forces producing the vibration, or its amount, could
well be so great as those which are often experienced in screw
steamships of immense engine power when under f uU steam ; and
yet these vibrations, although sometimes distressing ancLalmost
alarming, seldom do any actual harm. If any excessive tendency
to vibration should exhibit itself, which I very much doubt, it
would not be difficult to check it sufficiently by mechanical appli
ances. I do not feel at liberty to discuss, with my present information,
the relative cost of the Nicaraguan Canal and of the ship-railway
of Tehuantepec. I should require to give both projects more
lengthened investigation with that object in mind. All that I do
feel justified in saying is, that it seems to me that the advantage
as between the Canals of Panama and Nicaragua are all on the
side of the latter, from almost every point of view, while from the
point of view of United State citizens the preponderance of
advantage in favor of the Nicaraguan route is enormous.
As regards the comparative economy of transporting a ship's
cargo by canal or railway, I am inclined to beheve that the railway
would prove the more economical of the two.
It was stated in evidence before a committee of the House of

— 11—
Commons, by the chairman of the Great Eastern Railway Com
pany, on the 7th March, 1878, that coals could be profitably trans
ported by this company at the rate of £d per ton per mile ; and
this was confirmed by the locomotive superintendent of the North
western Railway, on the 21st March, 1878. If we assume that
the total distance to be hauled across the Isthmus of Tehuan
tepec is 150 miles, it would appear that a ship's cargo can be
profitably carried for that distance, in the ship, over'  _'st-
class railway, for $0.75 per ton. I arrive at this conclusion from
the following considerations: 1st, ^d, or one-half cent, per
mile gives $0.75 per 150 miles; and, 2nd, the weight of the
ship and car upon which she is transported appears to bear
about the same ratio to the cargo carried in the ship, when
f ully loaded, that the weight of a coal-car bears to the weight of
coals it carries. It was also stated in evidence, on the occasion
above referred to, that the weight of coal carried on one truck is
7f tons, and the weight of the truck 4£ tons. The paying load
is, therefore, about 58 per cent of the total ; and this is about
the proportion that the cargo would bear, in many ships, to the
total weight of the ship, car and cargo. These facts are suf
ficient to show that the transport by ship-railway, over a first-class
readiwith easy gradients, in a country where fuel is abundant and
labor not excessively dear, ought to be about the same per ton
per mile, for the cargo carried, as in England. If, however, we
assume it to be twice as expensive, the rate would then be $1,50
per ton across the Isthmus of Tehuantepec. I am credibly in
formed that at this time $20 per ton is being paid for the transport
of grain from California, round Cape Horn, to Liverpool.
It should be borne in mind that there are two elements in the
ship-railway plan proposed by Capt. Eads which tend to greater
economy than is obtained in the railway system of England:
1st, the ship-railway will be devoid of all curves ; and, 2nd, the
cargo transported will be handled wholly by machinery, and in
vast bulk.
I am afraid, Dear Admiral Ammen, judging from some indica
tions wliich I have observed in letters from your pen, that the
views which I have herein expressed concerning the ship-railway
will appear to you both unexpected and unsatisfactory. I shall
very much regret it if this be so, because to differ with an officer

—.12 —
of your experience and of your manifest fair-mindedness must
necessarily detract from one's own influence. At the same time I
find myself wholly unable to believe that there are many ships at
sea which could not, with proper appliances and the needful care,
be lifted, fully loaded, from the water, and transported upon rails ;
and if ships could not be thus employed as railway cars for their
Own goods, I should think it time to deal with the matter the other
way about, and make large cargo carriages which could take the
sea, and steam and sail efficiently there. I have, therefore, no
words but those of encouragement for a ship-railway, regarded
from my point of view as a ship-builder, accustomed for a hfe
time (which is getting now to be a long one) to the designing,
building, repairing and docking of both wood and iron ships ;
and while wishing no harm to the Nicaraguan Canal scheme, and
not having anything to say against it, I trust the ship-railway
scheme may also, for the credit alike of engineering science and
of commerce, be hereafter discussed by others with that dispas
sionateness with which, I am confident, it will always be treated
by you.
Will you allow me to add an expression of the very great sorrow
and pain which are everywhere felt in this country on account of
the attack made upon your President, also of our heartfelt sym
pathy with him in his sufferings, and of our admiration at the
heroism displayed by him throughout them. His name and his
noble endurance are upon every tongue here.
I have the honour to be, Dear Admiral Ammen,
Yours, very truly,
E. J. REED.