The Maritime History of the Great Lakes
Modelling Sail Vessels for the Lakes
Publication:
The Monthly Nautical Magazine and Quarterly Review (New York, NY), October 1854, pp. 9 - 16


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INLAND NAVIGATION.

MODELLING SAIL VESSELS FOR THE LAKES.

To achieve utility in the production of any class of shipping, it is necessary to consider carefully at least three grand governing conditions, which seem to demark the main outline of adaptation to commercial purposes. These elementary points may be defined as the nature of the trade and cargo to be carried ; the extent and depth of the waters to be navigated ; and the mode of propulsion adopted. Other considerations of detail will [p. 10]likewise enter into the theoretical design, and the points are not

few which should be definitely settled with regard to the manner

of building, rigging, and manoeuvring the vessel, before the

model is undertaken ; for we should never lose sight of the basis

of all success in ship-building, to wit : that the ship, like a watch

or a locomotive, is a unit in itself; one part must be studied

with reference to another, and the performance with reference

to them all. The strongest built and most costly finished ship

is, after all, best prepared to carve her fortunes on the deep,

when the designing mind and executing hand have been united

in the same person directing the operations from keel to truck ;

and, we may add with emphasis, that the commander's duty is

to develop those designs in using the ship.

Having arranged our investigations to our mind, we shall discover the corresponding model looming up to our inner vision,

and appearing in all its proper proportions and true shape. It

is with our mental eye we should first view our incipient architecture afar off, and examine it well before we conclude to tow

it into port. After we have submitted the distant ideal vessel

to the ordeal of nautical criticism, as an intruding stranger advancing to receive our sympathy and paternal regard, we are

prepared to adjust its form to the measure of capacity required.

The work of "making the model" is now fairly under way, and

we should grasp its configuration fast before our mind's eye,

until the labors of the hand have produced it tangibly before us.

Our task is not merely to fashion a block of wood into the likeness of something that floats the commercial element, but to

produce the exact counterpart of the living shapes which genius

has configured in the "lofts" of the mind.

By means of calculations, which, if not familiar to the modeller, may be found explained in Griffith's Treatise on Marine

Architecture, it is by no means difficult to approximate the requisite capacity for cargo, or space for passengers. Tonnage,

by dimensions, is no guide to determine the freighting capacity,

being a mere romance of legislation ; the displacement must be

the basis of our approximation. We will leave some remarks

on this subject to another article, adding only that it is best not

to be trammelled by dimensions, arbitrarily fixed, before the [p. 11]

model is begun. The length, breadth, and height of load-line

may be so determined that it shall contain the necessary buoy-

ancy to float the vessel and cargo at any given exponent of

capacity. Beyond this, we should have ample scope for the eye

and the instrument.

With this brief sketch of our manner of producing models, we

will take a trip to the lakes, and proceed to consider some of

the peculiar points of vessels adapted to commercial purposes

on the inland seas. On these waters, by far the most interesting

of any basins on the globe, the chief staples of trade are furnished by the agriculturist and the lumber manufacturer, and

consequently demand a natural fitness in the build of vessels

suitable for the transportation of each commodity, or, in other

words, a model adapted to the trade. Thus, lumber, being a

cargo which can safely be carried on deck, requires for its

transportation a shoaler craft, or one with less depth, relatively,

than a cargo of produce, which must be stowed under decks ;

and neither demands so much depth as vessels require which

are engaged in freighting cotton or light goods. There can be

no wisdom in loading lumber vessels with height of topside sufficient to stow all the cargo in the hold, for we would thereby

impair the carrying properties, and lose in sea-worthiness. Low-

deck vessels are, therefore, most profitable for this trade, and

may carry a large proportion of their cargo on deck. Cargoes

which require to be protected from the weather may be classed

as heavy and light freights; the former requires displacement,

and the latter space or stowage. High-decked vessels, of larger

capacity, are found best calculated for heavy freighting, and we

do not hesitate to state that our observation intimates that the

most profitable sail vessel built for freighting oats, or other light

cargoes of perishable goods, would be constructed with two

decks -- a main-deck and a spar-deck. The main-deck, at the

height of the load-water line, and the spar-deck seven or eight

feet above, with light topsides, flush spar-deck, with cabins on

the main-deck lighted from the sides. At present, the sail craft

on these lakes have but one deck.

But the draught of water ought, perhaps, to exercise the

greatest influence in the designs of lake shipping. Many of the [p. 12]

harbors and rivers afford the navigator no more than eight feet

of water, and but few can command ten feet, or more, over the

bars; and on the noted "St. Clair Fiats," the channel varies in

depth from eight to eleven feet from year to year, and in the

lowest stages of the lakes, the water has been known to stand

even below six feet. Among the most dangerous incidents in

the history of lake navigation, the inland mariner classes the

"making" of those shallow harbors, "pounding over the bar,"

with a heavy sea running between two breakwaters, or piers,

entering often literally the very jaws of destruction. A light

draught of water is, therefore, one of the most important points

to secure in this class of vessels.

But, strange to say, rare have been the instances in which

measures have been taken to accommodate the displacement of

vessels to so plain a necessity. Immense sums are expended

every year, together with a ruinous loss of time, where navigation is open but eight months in the year to "lighter" vessels

over the "flats," that ought to pass clear. We may account

for this in the prevailing notion that depth of hold and freighting capacity are the same terms, which is a mistake. The hope

of receiving the aid of the General Government to build, dredge,

and maintain suitable harbors on the Northern Lakes, has, no

doubt, deterred the adoption of shoaler models.

It is, however, true that the relative length has been extended

quite to the verge of practical limits, in some cases, partially to

secure the advantages of light draught ; and this feature, in

connection with the general adoption of centre lee-boards, with

very little outstanding keel, constitutes the distinguishing characteristics of the shipping on the American Lakes. There are

schooners, and, indeed, every variety of rig here, the largest

about one hundred and forty feet long, twenty-six to twenty-eight feet beam, and from ten to twelve feet hold. A few vessels are wider, relatively. The unparalleled length of these vessels endows them with remarkable fleetness, when compared in

their performances with shorter vessels of the same shaped ends.

But while still greater advantages of light draught may be obtained, by increasing the breadth, as well as the length, it should

not be forgotten that the lateral resistance will be diminished, [p. 13]

and the vessel will require more strength in construction. This

follows, because in such case the vessel will have increased stability, and consequently carry more sail; the absolute resistance

will be diminished, and, of course, the speed will be improved;

but, remember, the lateral resistance having been diminished

by lessening the draught of water, (unless a compensating surface of centre-board is provided,) you will gain nothing in

oblique courses, or, in other words, beating to windward.

It will be vain to expect that the qualities of speed by the

wind will prove to be connmensurate with the vessel's high character in free courses, or with leading winds. We say, then,

that long, wide, and shoal vessels require enormous centre-boards to enable them to sustain their reputation when working

to windward. The feat of sailing by the wind is a problem of

the least possible amount of absolute resistance, combined with

the greatest possible amount of lateral resistance, and the largest

capacity for sail. It is doubtful whether it will pay for freighting vessels, otherwise properly adapted to the navigation of

riiallow waters, to be qualified in the highest degree to contend

with head-driving gales. Vessels built for pleasure may well

claim to dispute this privilege.

In case it be not designed to increase the speed materially,

when adopting a liberal breadth of beam, the exponent of dis-

phcement may be enlarged, or, in other words, the buoyancy

Biay be augmented to advantage. But the mode of propulsion,

or the application of sail, must be duly consulted before deter-

Buning the outlines of proportion and shape, in order that the

model may be adapted to the peculiar evolutions required at

sea. This is a point seldom or never attended to; but we contemplate a live craft, and consider the rig as a very material

instrument in developing her points at sea.

First, as regards the vessel, and her mode of propulsion or

application of sail in adapting the one to the other, it may be

inferred that we will assume the stability and velocity, in connection with the lateral or side resistance, to determine the

basis of adjustment or choice. Thus it will be found that the

sloop which is the simplest of all rigs, requires the most stability; the fore-and-aft two-masted schooner comes next, then the [p. 14]

three-masted, and last the various rigs of square-sails, in the

order of diminished beam or stability. Brigantines and topsail

schooners require a large share of stability. This discrimination

in favor of square-sails with moderate stability, and fore-and-aft

canvas demanding greater beam, is principally with a view to

the ease and safety of working ship, and to the fact that in the

fore-and-aft rig the weight of canvas and spars must be borne

to leeward, and consequently the wind exerts a greater depressing effort on such sails ; whereas, in the case of square-sails, in

their rotation around the masts, the weight of propulsory power

is very little moved to leeward, and the depressing effort is the

smallest possible.

If the reader is conversant with the evolutions of the fore-and-aft and square rig at sea, especially before the wind, he will discover no difficulty in assenting to the distinction here laid down;

and if the nature of the navigation requires one kind of rig rather

than another, it should be furnished with the corresponding

model. Thus sloops appear best adapted for river navigation,

and they require great beam, flat bottoms, round sides, and large

lee-boards. The expansive basins of the North American Lakes

seem particularly inviting to the fore-and-after, and the various

modifications of the schooner rig, while the more hardy seas are

reserved for stately ships.

There is a fulness in all this that is pleasing to contemplate,

so we feel sure we are right, and consequently go ahead.

Sloops are not to be met with in our lake waters, and the fore-and-aft two-masted schooner has long been the favorite rig for

vessels under 300 tons ; and though we have seen fore-and-afters

above 400 tons, with proportionate beam, this rig becomes too

heavy ; and vessels over 300 tons had better be built longer, and

then adopt the three-masted rig. Of these there are various

modifications, and the best has not yet been generally fixed

upon. But it will be conceded by most judges, that square-rigged foremasts, especially for the larger class, must continue

to command a large share of nautical approbation. It may be

inferred that such great length as this rig requires is unfavorable

to celerity of movement in stays, but let it be remembered that

it furnishes great lateral resistance, with diminished absolute [p. 15]

resistance, and far head-reaching qualities. In addition, they

are furnished with two centre-boards, the after one to be raised,

if necessary, in tacking ship. The adoption of two boards has

followed partly as a necessity, and partly as an experiment, in

adding the third mast. We may remark that they cost more

than one board, and are not so effective. This rig requires fine

light ends, high, sharp bow, long midship body, with increasing

sheer towards the head and stern, and accumulated strength

amidships. It will yet be found necessary to introduce diagonal

trussing of iron on the inner surface of the frame, as upon the

larger vessels on the sea-board, in lieu of the arched strakes that

are now worked over the ceiling in the hold. To facilitate the

evolutions of such models at sea, it is not wise to be over-anxious in securing a superabundance of lateral resistance on the

ends beneath water, as this will impede the working ; better

depend on that furnished by the side and the centre-board.

But we must apprise the builder, that the fore-and-aft rig,

whether on two or three masts, requires great lateral resistance,

and shape for velocity, inasmuch as this rig is peculiarly well

adapted for oblique courses, and oblique courses demand velocity, in order to make it pay to contend with adverse winds.

We would prefer the square rig (or full vessels, or those which

do not hold on well, for this reason, were there no other: fore-

and-aft sails are best calculated for close-hauling, and close-

hauling demands great side resistance, with speed; and, on the

other hand, the yard will not come so close as the boom, and is

more in place on a vessel whose hull itself will not stand so

close to the line of its course.

Vessels intended for brigantines require their main-breadth

carried well forward, and the bulk of displacement contained in

the fore-body. The bow should be furnished with great lifting

power, and strongly built to withstand the great leverage of

head-sail, and the increased shock of the sea. The lifting power,

to which we refer, is developed in the shape of the immersed

fore-ship, and is consequent on presenting to the fluid the exte-

rior plane of the bow, inclined upward and forward, by which

it has a tendency to. lift above the line of the depressive effort

of propulsion. Thus the angle of anterior resistance may be [p. 16]

made to accomplish what buoyancy and raking of masts cannot

do. The brigantine has been a favorite rig, for a certain description of vessel, to which it seemed well adapted. There are

such brigs on these waters, 135 feet long, having a fore-yard 66

feet, carrying, at the same time, a fore-spencer and a main stay-sail to the deck, without interfering.

The topsail schooner rig requires less preponderance in the

bow and fore-body, may have finer lines, and with proper shape

and management is quite a match for any other style of craft,

when all the points of efficiency are fairly tested. And we

desire to say, for the benefit of any whom it may concern, that

if the lateral resistance lies chiefly in the board, and the vessel

comes quick hi stays, it is an erroneous manoeuvre to bring the

topsail aback, and pay off on the other tack with the due decorum of a ship of the line ; it is not required, and time is lost.

Let go and haul as soon as it is fairly to the mast, and the

schooner will be about and under way by the time the yards

are sharp up. We have seen bows so long and sharp under

water that they could not be paid off without gathering stemway, and it is plain that either the model or the manoeuvre was

wrong ; other conditions must decide which, inasmuch as both

are right in their place. Thus it may be seen, that from the

market boat to the queenly clipper, the ship is a chain of a thousand links, to be forged with systematic skill.


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Date of Original:
October 1854
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English
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Modelling Sail Vessels for the Lakes