Virginia. Board of Public Works.

Annual report of the Board of Public Works to the General Assembly ..., Volume 4 online

. (page 36 of 42)
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results would be more distantly felt and diflfused. It would
promote the commercial i >terest of the middle and western
States and bind them together, and also, with the country ly-
ing on the Lakes, by its immediate proximity to the Scioto and
the Muskinstum.

Considered in a military point of view, it may likewise be
asked whether James river is not as important as the Potomack
or the Susquehanna ? Its entrance will be effectually defend-
ed by the cross fires of the two formidable forts at Old Point
Comfort and the Rip-raps, which will afford complete protec-
tion to the coasting trade. As an interior line or base of ope-
rations, the central situation of a safe water communication
between James river and the Ohio, would, I think, offer in-
calculable advantages.

If the considerations I have presented here are correct, it is
D be regretted that no complete examination has been made
f the dividing summits between the James and Kanawha riv-
jrs; a well conducted survey to ascertain in a conclusive man-
ner the degree of practicability of a canal across the mountains,
by dispelling the doubts which hang over this great question,
would be of the highest importance, not only to the State of



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449

Virginia, but to several of the western States. Should the
scheme be demonstrated by such an examination and survey
to be quite practicable, (and it will not appear improbable that
it would be found so, when it is considered how near some of
the sources of both the eastern and western waters approach
to the top of the dividing ridge,) it would have an immense
influence on the view which should be taken of the i
ment of the upper navigation of James river.

The last remark I have to make on the canal, is re
its connexion with tide water. The old decayed loc
lower end of the basin cannot be maintained much h
would appear expedient to replace them by a line of st(
beginning somewhere near the Armory and terminating at the
Dock, some distance below Mayo's bridge, with suitable ba-
sins between them: they might probably be made for SlOO,000.
This improvement, with proper accommodations at the Dock,
would greatly benefit the coal trade; it would diminish the
cost of that which is exported, in consequence of which the
increased quantity of this article, which would then come to
Richmond, would very likely be alone sufficient to pay a fair
interest on the expendiiure: The Dock itself, in which the
State is largely interesteoVivould likewise be benefitted. And
we must besides anticipate the time when, the improvement
of James river being completed, the increase of business and
the certainty of arrivals will make it a great object to meet the
shipping with the canal boats.



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450

ON THE IMPKOVXMSNT OF THE

RIVER BY LOCKS AND DAMS, AND BY SLUICES.



Having, in compliance with your order, laid before your
honorable Board all the considerations which suggested them*
selves to me in r^ard to the prosecution of the canal along
the margin of the river from Maiden's Adventure to the mouth
of Dunlap's creek, I will conclude this report by an enquirjT
into the relative expediency and advantages of other modes of
improvement, which, though not positively required by your
resolution, may be considered an implicit and indispensable
appendage of the report /

I should, however, say but little on the subject, if I had to
make a comparison between the navigation of rivers with boats
managed by men, and that of canals with boats propelled by
horses. Experience has long since decided the question in fa-
vour of canals; and the principal objection to the improving of
the bed of rivers, has always been the want of a suitable pro-
pelling power. But the introduction of a new, powerful and
locomotive agent will lead me to consider the various modes
of improvement under a different point of view.

In this age of discovery, the application of steam as a moving
power, has produced a revolution in the mechanical arts. To
this powerful agent we owe the advantage of a convenient, ex-
peditious and safe mode of navigation: but its application as
yet, has been confined to deep and comparatively still waters.
Of late, however, some attention has been given to its intro-
duction in the various systems of inXernal improvements. On
the Susquehanna, experiments have recently been made to as*
certain the practicability of applying the steam engine to sluice
navigation. A steam-boat (the Codorus) has ascended the Sus-
quehanna up to the mouth of the Chenango. Of the capability
of steam-boats to ascend a river, there could have been no
doubt: for, the question being reduced to this simple statement:
If a steam-boat would move in still water at the rate of 10 miles
in hour, for instance; could it stem a current of 4, 5 or 6 miles
in hour, and how fast would it do it? the answer could not
be doubtful. The possibility of ascending a stream is not,
therefore, the principal question to be investigated; but, rather,



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. 451

whether the' application of steam power to sluice navigation
will| in all cases, be attended with real benefit; and also, whether
it could, advantageously, be introduced on a river improved
by locks and dams. .

As to canals, experience has taught that steam is not easily
applicable to their navigation, and that it would require that
they should be made of dimensions and in a manner different
from their usual construction; and also on a more expensive
plan.

The principal aim of all the improvements in navigation is
to obtain the most advantageous application of the most econo-
mical propelling power: and the chief advantage of a canal
consists in the facility of using horses in the towing of boats,
which cannot be emplpyed in sluice navigation, and are seldom
advantageously so in lock and dam navigation: the power of
a horse being equal to that of at least 6 men and much cheaper,
this circumstance alone would make canal transportation a great
deal less expensive than the navigation of a river. But, if
steam could be used as a propelling power, it is obvious that a
lock and dam improvement might be advanced towards an
equality with a canal. It is this important question that I now
purpose to investigate. As the suggestion is of recent date,
experience has not yet furnished precedents from which to
draw positive deductions: it is necessary, therefore, to recur
for information on this head to the very fundamental princi-
ples and data on which it depends, and to proceed in this in-
vestigation with cautious steps.



INTRODUCTORY REMARKS ON THE USB OF STEAM
IN NAVIGATION.

The most advantageous way of applying steam-boats to the
transportation of produce in open waters, is evidently in tow-
ing lighters: the propelling boat in this way draws less water;
and the whole train experiences less resistance, than if all the
load was collected in the leader. Of the possibility of using
steam-boats in this way, there never could have been any doubt.
They have been employed for some years past on the Savan-
nah river, on the Cayuga Lake, on Lake Champlain, on the Hud*
son, and probably on other waters. The only enquiry to be
made is relative to their convenience Imd expense.



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452

Steam-boatfl of 10 horse power may be made of such dimoD*
sions as not to require locks of an inconvenient size. I suppose
that they mip;ht easily be made to pass through a width of 14
feet, which would not be too great for locks made through
dams. This, or even a smaller size of steam-boats, appears
eligible, not only as regards the dimension of locks, but for
other reasons which I will advert to in the sequel.

I willy therefore, make all my calculations for a boat of this
capacity. The process would be the same for other dimen-
sions.

The price of transportation by steam-boats of all sizes in
open waters, (that is without locks,) seems to be established
generally at about one dollar per ton per hundred miles. On
the Hudson, Mississippi and other waters, this is said to be
very nearly the rate of freight: the velocity of the boats used
averages about 8 miles an hour. This speed is far from being
the most advantageous in the transportation of produce or mer-
chandize; and it is probable that it is assumed for the accom-
modation of travellers. But, here the subject of enquiry being
the carriage of produce, it is proper to determine what should
be the speed adopted, and how it would afifect the pmce of
trannportation.

When a vessel moves in a fluid, it experiences from it a
resistance which is well known to be proportional to the
square of the velocity; and consequently, since the propel-
ling power must be increased in proportion to the resistance,
it follows, that it would require a four-fold power to move
a boat through water with a two-fold velocity; a nine-fold
power for a three-fold velocity, &c.; that is, the propelling
power must be increased in proportion to the square oj the
velocity intended.

Hence, if two equally loaded boats perform the same trip,
one with a velocity of 8 miles, and the other with a velocity
of 4 miles an hour, the former will require four times the pro-
pelling power of the latter; and, because it will perform two
trips while the other makes but one, the expense of its mov-
ing power will be double that of the slower boat, and this ex-
pense must of course be paid by the freight.

In the same way, if the speed of the first boat was accele-
rated to 12 miles, the propelling power must be nine times as
great: but, on the other hand, performing three trips during
the same time, its expense would be three times as great, and
so on for any rate of velocit)-.

From this it must be concluded, that the expense of a pro*
'oelling power to move a loaded boat is in direct proportion



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458

io t he vehcitp given; or^ in other words, the expense of trans-
parting freight is proportional to the velocity with which it
is carried. ^

An augmentation of speed may be obtained, either by an in-
crease of power, or by a proportional reduction of weight: but
it does not quite follow, that the actual quantity of freight car*
ried would always be exactly in the inverse ratio of the speed
of transportation; that is, that exactly half the freight, for in-
stance, would be transported by the same power with double
the velocity: in all cases, part of the power is lost in moving
the boat and engine (if steam is used) and other things, whose
weight must be deducted to obtain the useful effect produced
by the propelling power; by which deduction, the ratio of the
freights corresponding to different velocities is altered to the
still greater disadvantage of rapid motion. All these conclu-
sions are verified by daily experience, and instinctively applied
to transportation.

The useful effect of a propelling power is, in general, esti-
mated by the product of the freight carried multiplied by the
distance to which it is transported in a certain unit of time. The
measure of the power itself is usually estimated by the height, to
which it is capable of raising a certain weight in a certain time.
Thus, in Steam Engines, whose power is generally coi^ipared
to that of horses, the horse power is most commonly estimated
to be equal to d3,000lb8. raised one foot in one minute; or, in
another way, 150lbs. raised 2i miles in one hour. According
to this standard, and the foregoing remarks, the freight trans-
ported by a steam-boat of 10 horse power at different veloci^
ties, would be as follows:



Velocity in miles.


Useful tons moved.


Useful effect in








tons moved I mile.


2 - - -


- - 400


„ •


.


«


800


2J - - -


- - 255


-


.


*


638


3 - . -


- - 175


. . .





-


525


3J - . .


- - 127


-


.


.


445


4 . . .


- - 95


• '


-


-


380


5 - - -


- - 58


-


.


-


290


6 - - -


- - 38





.


-


228


8 - - -


- - 18


-


-


-


144


10 - - -


- - 9


-


-


-


90



58



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454

The numbers in the second column do not include the
weight of the apparatus: it has been deducted from the actual
freight which would be moved, if the engine was stationary
and had not to transport its own weight

This table shews how much less is to be expected from
Steam-boats moving with a great velocity than from slower
rates. These important results, which are not generally duly
appreciated, apply to any other kind of propelling power.

In this, consists the chief disadvantage of sluice navigation;
for, if a current run through a sluice at the rate of 5 miles an
hour, for instance, it must be stemmed by a power capable of
a velocity of at least 6 miles an hour; so that the ascending boat
is actually in the same situation as if it moved at that last rate,
and consequently is no,t capable of carrying more than 38 tons,
as shewn in the table, if propelled by a 10 horse power; or 3.8
tons by one horse power; or, at the highest estimate, 1 ton if
moved by 3 men; and, with that weight, it advances only one
mile an hour through the sluice; so that, though there may be
many long ponds of smooth water, the intervening of such
sluices forbids large loads to be carried on them.

The daily expense of a steam-boat of 10 horse power may be
estimated as follows:

30 per cent, on the cost of the boat and engine,
valued at 03,500, for interest, decrease of
value, hazard, renewals and repairs, allowing
only 300 working days.
For captain, - - -

Engineer, - • -

Two hands, • - -

Fuel, li cord of wood per day of 12i hours, or
from 15 to 20 bushels of coal,

• Total for each working day, H 12 50

Which, since the boat would perform 100 miles in a day and
carry 18 tons, would be about 70 cents per ton per 100 miles.

To this must be added the expense occasioned by delays,
stoppages, loading and unloading, which depend on many un-
certain circamstances, and on the distance of uninterrupted
transportation. Supposing the time lost by these causes to be
about one-half the time of travelling, which I think very am-
ple, 35 cents per ton must be added to the above, which will
give I 05 for the expense of transporting one ton a hundred
miles on slack and open waters. Indeed, some deduction
should be made for some fuel saved while the boat is stopped



1^3 50


3 00*


2 00


1 00


3 00



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455

for any length of time; bat it is better to err on the safe side.
This result agrees nearly with the rate of freight above stated;
it would be still less for boats of greater burden, on which the
expense of attendance does not increase in proportion to the
size. ^

Having now established the price of transportation in a boat
moving at the rate of 8 miles an hour, it is proper to enquire
how much it will be reduced by lower rates of velocity.

The expense of delays, stoppages, &c will evidently be less
in proportion, when the boat moves slower and carries much
freight; but my object being to make a safe estimate, I will
still continue to state it at 35 cents per ton per 100 miles.

The expense of transportation alone, being inversely, as the
quantity of freight transported during the same time, may be
easily calculated by dividing the expense per hour, by the use-
ful effect expressed as above, in tons transported one mile in an
hour. The cost of the hour is jll for the steam-boat; and may
be estimated for each lighter and the man in it, at 8 cents:
Each lighter is supposed to carry from 25 to 30 tons.

Thefollmoing table exhibits the cost of transportation per
ton per 100 miles for different rates of velocity.



mUesper
hour.


Usefid effect in
in one hour.


jsrvmberof
Ughtero:


Expense of
per ton per 100


Do. -with the ad"
dition of 35 cents
per ton per 100
ndho amwedfor
deU^o, stoppage,
^c.


8 -


. 144 .


- -


70 cents.


105 cents.


6 -


- 228 -


. 1 .


47 "


82 "


5 .


- 290 -


. 2 .


40 <«


75 **


4 -


- 380 -


- 3 -


33 "


68 «


3i .


- 445 .


. 5 .


31 «


66 «


3 .


. 525 -


- 7 -


30 "


65 "


2i .


- 638 -^


- 10 -


2S "


63 <«


2 -


- 800 -


- 15 .


28 "


' 63 «



This table shews that much is gained by reducing the velo-
city to 3i or 4 miles an hour: but a smaller speed, when the
load is distributed among lighters^ does not seem so advanta*



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456

geous: a train of 7, 10 or 15 lighters would add more to the

incumbrance than to the profit.

The expense of transportation here exhibited, would be still
less if the distance travelled without interruption was greater^
and th^ trade well regulated; for, then, lighters might be load-
ing while the steam-boat would perform a trip, and be ready
to be taken in tow upon its arrival at each place. By this
means the sum of 35 cents per ton allowed for delays, stoppa*
ges, loading and unloading would be greatly diminished.

I do not think that I have underrated the expense of tha
steam-boat and lighters; but, even if I had, from the last re-
mark it is obvious, that much might yet be gained by judicious
management.

The most eligible degree of speed will of course depend on
the nature and quantity of the trade, within the limits, how-
ever, of 3) and 8 miles an hour, which seemed to be fixed by
the preceding table.

The size of the steam-boat itself must depend on the trade,
the distance of the extreme points, &c. Large steam-boats
would, in proportion, be less expensive; but, unless plying
between two large and commercial places, they could not make
a load so easily. On this account small boats suit best on a
river where the trade i^ not concentrated, as is the case on
James river.

In a system of locks and dams, the size of the locks is an-
other consideration which advises smaller dimensions. Boats
of moderate size require, besides, less capital, and are, on this
account, more likely to- be preferred. I have supposed that
boats of 10 horse power would be used: they would, I think,
be of a very eligible size: smaller ones would likewijse be ad-
vantageous; especially in the beginning of this system of navi.
gation.

Having obtained these preliminary data relative to open and
slack water, I will proceed to apply them in the first place to

SLUICE NAVIGATION.

In the infancy of a country the first improvement in naviga-
tion which suggests itself is that of the natural bed of rivers,
by clearing their channel and opening sluices through their
shoals. So far as this goes to remove obstructions and to en-
able small boats, under the management of about 3 or 4 men,
with a load of a few tons, to move down the stream and to re-
turn with a light load^ it is attended with benefit; and, with all



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45T

its imperfections, this navigation is even preferable to a road.
But| beyond this degree, I think that it is an error, on a rapid
river, to incur an additional expense for the enlargement of
sluices; for, the strength of the current increasing with the
size of the sluice, and moreover, the power necessary to move
a larger boat increasing likewise with its dimensions, a proper-
tional number of hands is requisite in the boat; and conse-
quently, nothing is gained either in point of time or power*
It generally happens, therefore, that when a river has much
h\\, the increased expense of its numerous sluices soon proves
disproportionate to the result obtained; and that, after many
fruitless attempts, this kind of navigation is abandoned and a
more perfect improvement resorted to.

Sluice navigation has ever been objected to, not only on
account of its uncertainty and danger, but also of the impracti-
cability of applying to it a cheap and uniform power. But^
what I conceive to be its greatest defect is, the waste of power,
of whatever nature it may be, which it necessarily occasions.

In ascending a sluice, a boat must be propelled with a pow-
er capable of giving to it a velocity superior to that of the cur*
rent; and consequently, though its progress is slow, the power
exerted is exactly the same as that which would give to the
boat in still water a velocity equal to that of the current in the
sluice added to the actual speed with which the boat stems it.
The propelling power, according to what has been said before,
(page 452,) must then be proportional to the square of this
virtual or relative velocity of the boat; or else, if, as is usu-
ally the case, the power remains the same, the weight moved
must be reduced in the same rapid ratio; and indeed to even
a much lower rate, when the power of men is used, for it is
well known that this power, like the strength of animals, de-
creases rapidly when the speed, whether real or virtual^ is
increased. In going up, therefore, on account of the sluices
to be stemmed, only very light loads can be transported, and
but little useful effect is produced. In going down the stream,
on the contrary, rapid sluices add to the danger of navigation,
without increasing the useful effect, since prudence forbids
lai^ loads, which, besides, would lessen the speed in the ponds
of still water, for which the load must then be calculated.

These remarks apply likewise to steam navigation. A cur-
rent running at< the rate of 5 miles an hour, for instance, may
be stemmed by a steam boat capable of a velocity of 8 miles
an hour; but then, though the actual velocity of the boat is
only three miles an hour, its load must be suited to its virtual



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relocify of 8 miles an hour: and oonsequeDtlyy the useful e£>
feci of a 10 horse power will be, according to the above tabl^
18 tons; which being moved only 3 miles an hour, will be the
same as 54 tons moved one mile: and the expense for the dis-
tance in which this current has to be stemmed, will be to that
through still water, as the useful effect 144 of the same steam-
boat, moving 8 miles an hour in slack water, is to 54; that is
almost three times as great On a river, therefore, which has
a rapid fall, the multiplied delays resulting from the current in
sluices, and the consequent diminution of useful effect would
materially increase the expense of steam navigation in ascend-
ing; while, on the other hand, the frequent and dangerous ra«-
pidity of the current in descending, would so often xorbid the
operation of steam as to render it an almost useless agent

But, on a slu^ish river, which has but few rapids improved
by sluices, though the current of the sluices would, for the
above reasons, prevent the carrying of laige loads, still this
would in part be compensated by a degree of speed, which
would be but little affected by the occasional check of a few
sluices. On such a river also, the operation of steam would
so seldom be interrupted in descending, that it would be found
an efficient and economical agent

The cost of the improvement of a river of this nature by
sluices, would be inconsiderable when compared to that of a
canal; and might, frequently too, be much cheaper and other-
wise more expedient than a lock and dam navigation.

Of this kind is, I think, the Kanawha river ; and it was
chiefly in reference to it, that I have been induced to make the
preceding remarks. I have heardHhe opinion expressed, that
the improvement had rather injured than benefitted the navi-
gation; and, even that steam-boats would not answer on the
Kanawha,

From what I have said above, it will appear, that I do not
think the making of large sluices an advantage, so long as nea
are employed as the propelling power; and especially with
large, heavy and unmanageable boats, as those used on the
Kanawha: in coming up the sluices, the crew of the boat has
to give to it a virtual velocity, which, as remarked just above,
lessens the useful effect in a rapid ratio; and, though there may
be much still water, the load must, notwithstanding, be suited
to the swiftness of the sluices; and but little can be transport-
ed: and here, besides, we have not, as with steam, the advan-
' <3;e of speed in the ponds, because the day's work of men is li-

ed,and israpidly shortened by anacceleratedmuscular action.



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At high water, when the current is swift, these large boats
must be very difficult, and I may say, impossible to push op;
for then, a virtual velocity would be requisite which men can*
not give.

In descending, on the contrary, the current^impels the boat
forward with a rapidity, which takes the controul of its mo-



Online LibraryVirginia. Board of Public WorksAnnual report of the Board of Public Works to the General Assembly ..., Volume 4 → online text (page 36 of 42)