The present port of Havre is absolutely insufficient to answer the ever
increasing requirements of commerce. Its entrance, which is too narrow and
not deep enough, does not permit steamers to go in, come out, and perform
their evolutions with the rapidity required by our epoch. So they are
gradually abandoning our port, and going to load and unload at Anvers and
elsewhere. A large number of wise heads, who are anxious about the future
of this port and our national interests, have devoted themselves to
finding a means of enlarging it, not by dredging _new_ basins, which would
prove ruinous to the budget and useless in twenty years, but by installing
a true roadstead at the entrance to the present basins.
[Illustration: FIG 1.--PLAN OF THE PROJECTED ROADSTEAD AT HAVRE.]
Upon the maps of the hydrographic service may be seen, under the name of
the Little Roadstead, a vast extent of sea nearly two kilometers wide by
three to four in length, bounded upon one side by the heights of Heve and
St. Adresse, and upon the other by the rocky line of Eclat and of the
heights of the roadstead (Fig. 1). This Little Roadstead, so called, in
order to become a genuine one, would have to be protected against the
great waves of the open sea. To thus protect it, to close it as quickly
and as cheaply as possible--that is the problem.
In 1838, Charles de Massas presented a project (the first in order of
date), which consisted in constructing upon the Eclat reef a semi-lunate
dike, and a breakwater at Cape Heve. Moreover, upon the emergent parts of
the Eclat reef and heights of the roadstead he proposed to erect two
forts.
[Illustration: FIG. 2.--LEWIS' FLOATING BREAKWATER.]
The defense of the port of Havre is a very important question, and one
that appears to be completely abandoned. Since Engineer Degaulle in 1808
advised the erection of a fort upon the Eclat, and requests have
periodically been made and projects drawn. The requests are forgotten, but
the drawings are in the Ministers' portfolios, and if France should
to-morrow have a war with a maritime power our great northern port might
be destroyed and burned by the smallest squadron.
Some years after Massas' project, two officers, Deloffre and Bleve, and an
engineer named Renaud, received a commission to search for a means of
closing a portion of Seine Bay. These gentlemen advised the erection of
two dikes, one on the Eclat shoal in the very axis of this reef, and the
other at Heve. Between these two masonry dikes was to be placed a floating
breakwater. This project, which was submitted to Admiral de Hell in 1845,
had a favorable reception, and the Admiral especially applauded the trial
of breakwaters, "which were much talked of in England, although the
effects that they might produce were not well known." Deloffre, Bleve, and
Renauds' project comprised two forts--one to the north and the other to
the south of the roadstead. For a long time nothing more was said about
it, and it is only during recent years, when the peril has become imminent
for Havre (threatened as it is of being abandoned even by the French
transatlantics), that the question has again became the order of the day.
[Illustration: FIG. 3.--FROIDEVILLE'S FLOATING BREAKWATER.--END VIEW.]
Mr. Bert, a merchant, would protect the Little Roadstead by means of two
jetties, 1,000 and 1,600 meters in length, built, one of them upon the
Eclat and the other upon the eminences of the roadstead. These would be
constructed by forming a foundation of loose rocks, and using earth and
brick above the level of the water. Mr. Vial has likewise proposed a
rockwork of 2,000 meters in length, to form a dike 10 meters in height and
width, whose platform would be on a level with the highest tides.
Next comes the more recent project of Mr. Coulon. Seeing that it is the
deposits of the ocean and not those of the Seine that accumulate upon the
estuary, Mr. Coulon advises the construction of a dike about 2,000 meters
in length, starting from the Havre jetty, and ending at the southwest
extremity of the shoals at the roadstead heights, and a second one
returning toward the northwest, of from 500 to 1,000 meters. A third and
very long one of not less than 8 kilometers would be built from Honfleur
to the Ratier shoals.
This latter one, in contracting the bay, would contribute to increase the
force of the current, which, throwing back at the ocean its mud and
pebbles, would give us the depths of 15 and 20 meters indicated on the map
of Beautemps-Beaupre.
This year, again, two projects have arisen; one of them due to Mr.
Thuillard-Froideville, and the other to Mr. Hersent.
According to Mr. Hersent, it would be necessary to surround the Little
Roadstead with an insubmersible dike built upon the rocky shoals, which
would begin at Cape Heve (which it would consolidate) and end opposite the
entrance to the port at 1,600 meters from the jetties. Through it there
would be five passages. Afterward another dike would be constructed,
starting from the shore and running to meet the jetty designed to inclose
the Little Roadstead. On turning the angle at which it met the jetty it
would be continued as far as to Berville. Finally, a third dike, running
from Honfleur to Berville, would complete the system.
Mr. Hersent's project, which is one of the most remarkable of those that
have been proposed, has one fault, and that is that it would require
twelve years of work, and cost 158 million francs.
Mr. Thuillard-Froideville, completely renouncing masonry dikes as being
too costly and taking too long to construct, proposes to inclose the Havre
roadstead by means of floating breakwaters. As we have already seen, the
use of these between Cape Heve and the Eclat shoals had already been
proposed in 1845. As the project was abandoned, the models of these
breakwaters are rare.
In Bouniceau's "Marine Constructions" we find a curious figure, a sort of
open framework of clumsy form anchored in a singular manner, and
surmounted by rooms for watchmen, semaphores, posts for the shipwrecked,
etc. It is, indeed, the most complicated and most impracticable type that
could be imagined.
Mr. Lewis' model, which was exhibited last year at the International
Fisheries Exhibition, was, on the contrary, one of the simplest. It
consisted of a strong piece of wood of nearly triangular section, the
sharpest angle of which, being turned oceanward, was designed to cut the
waves and cause them to break over it (Fig. 2). If, by favor of divine
Providence, this breakwater, which presents absolutely plane surfaces to
the shock and pressure of the waves, is not broken to fragments in the
first tempest, it will certainly acquit itself of the _role_ for which the
inventor destined it. When we have a system of resistance to the sea,
anchored and facing a certain direction, and consequently not being able
to revolve around its axis as vessels do, care must be taken not to give
it entire surfaces.
[Illustration: FIG. 4.--FROIDEVILLE'S BREAKWATER.--MODE OF JOINING THE
PARTS.]
Mr. Froideville's breakwater consists of a framework 25 meters in length,
and 9 in height and width, and having the form of an irregular 5-sided
prism (Fig. 3). The smallest side of the prism is designed to serve as a
flat keel. The axis is formed of a metallic float, from whence start radii
that form the skeleton of the framework, and that are designed for
connecting the center with five long spruce beams that form the angles of
the prism. To these beams are affixed the cross pieces that form the
openwork sides. Five long pieces of wood parallel with the beams, but not
so strong as they, protect the cross pieces and secure them against
breakage in the middle. All the angles of the breakwater and all points of
juncture of the pieces are protected with iron, and it is in order to
counterbalance the weight of all this iron that the central float is
used. Parallel with this first breakwater, there are two other and smaller
ones, which are designed for reducing the effect of rolling as much as
possible. Reduced to a single float, the breakwater might remain under the
waves too long, but, owing to the two others, it rights itself, warps
around, and always presents the spur of its sharp roof to the wave.
In order to prevent the breakwaters from clashing against each other, they
are united end to end in a very simple and ingenious manner. From each of
them there starts a deeply inserted iron bar which terminates in a journal
that permits the breakwater to oscillate. Between these two bars there is
a sort of swivel, whose pieces, in playing upon one another, give the
breakwaters elasticity, while always holding them apart (Fig. 4). From
each side of the swivel start the branches of a stirrup iron to which the
anchorage chain is attached. This latter is of steel, without solderings,
and it is so perfectly constructed that no breakage need be feared. To the
other extremity of the chain is attached an anchor having two flukes,
which both engage with the bottom.
Mr. Froideville proposes to set up two lines of these breakwaters, for a
length of about 7½ kilometers, starting at the north from Cape Heve,
taking in depths of 15 meters (the best that are found in the Little
Roadstead), passing in front of the Eclat shoal and the heights, and
ending opposite the entrance of the present port.
The first row is designed for breaking the force of the waves, and the
second for lending its aid in times of high tempests, and stopping the
surge that has escaped from the first.
The extreme simplicity of this project has permitted its promoter to
affirm that in a few months, and with nine millions, he can inclose the
Havre roadstead.
The Little Roadstead, being thenceforward protected, will become an
excellent port of refuge in bad weather. In addition, a system of
lighters, or, better, a few floats connected with the shore and forming a
rock, will permit vessels to take on their cargoes with great rapidity.
Mr. Froideville's project presents the further advantage of rendering it
easier to put the port of Havre quickly in defense. A certain number of
floating batteries, anchored behind the breakwaters and protecting the
advances of torpedo boats by means of their firing, would make a
formidable defense. Not having to perform any evolutions, they might
without danger be invested with armor plate thicker than that of ordinary
ironclads. In order to complete the system, there might be erected upon
the Eclat shoal an ironclad fort like that which defends the entrance of
Portsmouth.
An English chronicler of the fourteenth century, in speaking of his
country, places it above all others, and declares that men are handsomer,
whiter, and purer blooded there than elsewhere, and he says that this is
so "because it is so." We would not like to imitate his naive reasoning,
and yet, for defending the very original system proposed by Mr.
Froideville, we have only our conviction, which we share, moreover, with a
large number of sea-faring men and engineers. Mathematics are powerless to
predict to us with accuracy the manner in which the floating breakwaters
will behave, but experiment remains. Let the promoter of the project,
then, be given authority to inclose a few hundred meters, and if, as we
suppose, the breakwaters shall remain immovable in a northwester, a
maritime revolution will have been brought about.--_La Nature._
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