_That the Way to get a Sailing Boat off the Shore, when she is fast by
any Accident, is to let go both or all the Sails, and stand at her
Head, and push with a Sprit._
This Error, though it may seem ridiculous to those who have been brought up
at Sea, and understand Sailing, is nevertheless very common in Inland
Rivers, where Sailing is but little understood. You may very frequently see
fresh-water Sailors, as soon as they find that their Boat has struck,
immediately let both their Main-sail and Fore-sail fly, after which they
all run to the Head of the Boat with Sprits, and begin to endeavour to push
her off; which Method is contrary to the Rules of Mechanics, and therefore
of Sailing.
A Boat or Vessel of any Size (a 90 Gun Ship moving upon the same Principle
as the smallest Cutter,) is acted upon by the Powers which are the Cause of
her Motion as she swims in the Water, in the same Manner as a Lever of the
first Kind, whose Center or Prop is between the Power and the Weight. To
explain this, let us suppose a Boat, instead of Swimming in the Water, to
be upon dry Land, and to have her Mast run quite through her, and fastened
into the Ground, upon which she might be turned at Pleasure, as upon an
Axle-Tree: In this Case, as her Mast is rather nearer her Head than her
Stern, it would be more easy to turn her Head round by laying hold of her
Stern, because there would be a Mechanical Advantage, by the greater Length
from the Stern to the Mast, than from the Head to the Mast. And in whatever
Direction the Stern of the Vessel is turned, her Head must move the
contrary Way, and vice versâ. Now, the same will happen to a Vessel in the
Water; if you push her Head in one Direction, her Stern will move in the
other, and vice versâ. So that a Vessel under Sail with a Side-wind, may be
called a Lever of the first Kind, both whose Extremities are kept in a
Ballance by the Sails and Rudder; Forces which keep continually acting upon
her. The Rudder may be considered as a Kind of Moderator, which is to
interpose when the Sails which are before the Mast, or those which are
behind the Mast, or abaft, overpower each other, and destroy that Ballance
which a Vessel rightly trimmed very near preserves of herself. It must be
observed, that the Sails before the Mast of a Vessel, and those behind it,
act in contrary Directions. Those which are before the Mast turn her Head
from the Wind, and those which are behind it turn her Head towards the
Wind.
By this Time, we see the Impropriety of letting both the Main-sail and
Fore-sail of a Vessel go, when she strikes upon Ground, and then running to
her Head in order to push her off: For first, concerning the Article of
going to her Head to push her off, if she is a small Vessel, the Weight of
two or three People at her Head will press that Part, which generally
happens to be the Part upon the Shore, still closer down; which is a Thing
so well known to every Waterman, that we shall say no more about that. Now,
as to letting both the Sails go, they might with as much Propriety both be
set, for as they act in contrary Directions, they destroy each other's
Force, if the Vessel is well trimmed; so that a Vessel will come off the
Ground no sooner for letting both the Sails go. The Method that I should
take in a Case of that Kind, would be to set the Main-sail and let the
Fore-sail fly, and if that would not do alone, to assist the Main-sail by
pushing at the Windward-side of her Stern with a Sprit, both which Forces
acting together, namely the Main-sail and the Sprit, would in all
Probability put her Head about so as to bring it beyond the Point from
which the Wind blows, which Point after I had got her past, I would set the
Fore-sail to the other Tack, and let the Main-sail go; and by that Means,
the Fore-sail would put her Head almost round; then the Main-sail might be
set, and after Sailing back so far as to get quite clear of the Place where
the Vessel stuck fast before, she might be tacked about again, and pursue
her intended Voyage.
I don't presume to say, that this is the very best Method of getting a
Vessel off the Shore; as those who have been used to the Sea may have a
more ready Method still: But I do say, that it is a Method which is
consonant to the Principles of Mechanics, for which Reason, it may very
safely be put in Execution, either at Sea or in fresh Water.
* * * * *