One day, while standing talking to a builder, we were joined by the
owner of a naphtha launch who was desirous of having his vessel rigged
as a yawl, and had come to get the builder's opinion as to what the
change would accomplish and cost. In response to an inquiry as to
what speed he might expect to get out of the craft under canvas, the
builder answered, "four miles." "Then," replied the owner in jubilant
tones, "she will go eleven miles, as I get seven out of her now without
any sail." He was greatly surprised, and rather suspicious of our
knowledge, when we informed him that if sail increased the speed of his
craft over her maximum to the extent of half-a-mile an hour, he might
consider himself fortunate. Now, this man is by no means a lone bird
in his belief; he shares the misconception with many launch-owners and
others. Like some of our popular authors who write sea stories that are
not sea stories, the average man firmly believes that steamships can
and do sail, and it will take many years of pounding to get this idea
out of the public's head. There are afloat steam vessels that can and
do sail, but they are sailing vessels equipped with engines. In former
times almost all ocean-going steam craft could work to leeward under
canvas, but they, unlike the vessel of to-day, were heavily rigged,
most of them carrying full sets of yards forward, and spreading many
thousand feet of cloth. The steam vessel of this age, when put to using
sail, simply drifts. Except as a check to rolling, the sails carried by
steam vessels are of little use.
Now, to the question of what use is sail as an auxiliary power. In
vessels of a speed exceeding ten knots, it is of little or no use,
except when due to the form of the hull, or for other reasons the slip
of the screw is excessive. As, for instance, in a vessel towing others,
such as sea-going tugs, where the actual speed is one-half of the screw
speed, sail is an aid. Again, in a vessel of bad form, when, frequently
owing to the weight on the engine it is unable to run at its highest
working speed, sail is an aid, as it lifts some of the weight off the
engine, and allows an increase of revolutions without an increase of
fuel expenditure. For this purpose, fore-and-aft canvas is of doubtful
utility, the square sail being far better. But in high-powered,
fine-lined vessels auxiliary sail is of no use whatever. The little
that might be gained by employing it under the most favorable
circumstances is offset by the retarding effect of the windage under
unfavorable circumstances.
A vessel whose screw speed is eight knots and whose actual speed is six
knots has a slip of twenty-five per cent. Supposing that her sail power
is sufficient to drive her five knots or three knots in excess of the
slip. Now, if her speed be increased to eleven knots by using canvas,
it must not only take up the slip, but induce an acceleration of the
engine, so as to give an additional screw speed of three knots--an
increase of 37-1/2 per cent. over the working speed of the engine. This
is practically impossible. No engine is built to run at a speed of
37-1/2 per cent. over its working speed, yet unless the screw travels
as fast as the hull, it is useless. It is exactly the same thing as
when trying to row a boat running under sail; unless you move the oars
faster through the water than the boat is moving you do not assist in
the propulsion. Reasoning from this, we may lay it down as an axiom,
that: When a vessel's maximum speed under power exceeds her maximum
speed under canvas, the use of sail in conjunction with power will not
increase the speed beyond the percentage of slip.
When mechanical propulsion is the auxiliary power, we have a different
problem. Take a vessel capable of being driven by sail at a speed of
eight knots, and by her engines alone at four knots. Now, if she be
sailing at a speed of eight knots, and we start her engine to make
the number of revolutions necessary to induce a speed of four knots,
the screw, not traveling as fast as the hull, will be dragged to
the amount of the difference between its speed and the speed of the
boat--four knots. In that the screw shall have a propulsive force it
must be driven at a speed to exceed eight knots, an increase of over
100 per cent. Reasoning from this, we may lay it down as an axiom,
that: A vessel whose maximum speed under sail exceeds her maximum speed
under power will not increase her speed by employing sail and screw
conjointly.
While auxiliary sail is of little or no value, auxiliary mechanical
propulsion is. But its chief value lies in it as a substitute, and
not as an auxiliary. The wind--the fuel of the sail--is not only a
variable quantity, but frequently an absent one. A small vessel, such
as are the majority of our cruising yachts, seldom exceeds a speed of
eight knots, and as a general average taken through a summer's cruising
do not log more than four, much of this low average is due to the hours
spent in calms and light airs; and if we add the time lost in waiting
for a breeze, the average will fall still lower. A yacht in sailing
100 miles in the usual summer weather takes, we will say, twenty-five
hours. Sixty miles of this is made in a fair breeze in ten hours, then
six hours in which she makes ten miles, leaving nine hours in which to
make the other thirty.
60 miles 10 hours. 6 miles an hour.
10 " 6 " 1-2/3 " "
30 " 9 " 3-1/3 " "
Average for 100 miles, 4 " "
Let us suppose that a similar craft is fitted with a motor to drive
her at a speed of five miles an hour. She voyages 100 miles, the first
sixty in ten hours. During the doldrums she uses her power for six
hours, and makes thirty miles, and in sixteen hours has covered ninety
miles against the sail yacht's seventy. Having made the distance at an
average speed of 5-5/8 miles, she is within sight of her port when the
other is thirty miles off.
Last summer I ran thirty-eight miles in fourteen hours in a small
sloop. Thirty-two miles of this distance was made in eight hours, the
remaining six miles taking six hours to cover, and if you analyze a
set of cruising runs you will see that mine was an exceptionally good
performance. I usually, in cruising, figure on making an average of
three miles, thirty miles being a fair day's work and forty a good
one, while a fifty-mile run is possible only once or twice during the
season. This is in a boat whose maximum speed is seven knots.
I have not the slightest doubt but what a man with a yacht fitted with
a motor capable of driving her at a speed of five miles, and using the
engine only as a substitute for sail when the wind is dead or fickle,
could cruise twice as far and see twice as much as one who depended
solely upon canvas. This is a deal to promise, but no doubt those who
have had a long experience in cruising in our Eastern waters will
underwrite the opinion.
But while auxiliary power has its advantages, it also has its
disadvantages. It increases the expense; it takes up room in the boat;
it is noisy, and, to a certain extent, disagreeable, due mostly to the
use of a fuel which is not equal, odoriferously speaking, to genuine
wood violets. But its chief drawback is that its use tends to make
cruising less toilsome and hazardous. Like all modern
"Inventions that save our seamen's lives,
And murder the breed of sailor men,"
its effect is to discount skill and pluck, to take away from voyaging
that uncertainty which is the chief charm of the cruiser's existence.
The fact that you leave port with a certainty of getting to your
destination on time, barring accidents, makes somewhat monotonous an
event that otherwise containing a large element of chance induces a
corresponding degree of excitement. There is probably no pastime so
tiresome to an active man as steam yachting, especially if it be in
familiar waters. A steam yacht is a lazy man's palace and an active
man's prison. Except when there is a race or a difficult bit of
navigation, I would as soon run a trolley car as a power boat. But,
then, happily for the world, we are not all taken off the same molds.
Many men yacht for pleasure, and find such pleasure in idleness. I
don't. I find my pleasure in physical exertion, and in opposing what
skill and knowledge I may possess to the task of getting the better of
the elements. But as age and rheumatism tighten their grip, my heart
is being gradually weaned from the sail, and I find myself thinking
seriously, if, after all, it will not be better to have a little power
under the deck to fall back on at certain times.
_ON REEFING_
_Precaution is the mother of safety._