It was on this island that the distinguished Major Sabine conducted his scientific and interesting observations upon the swinging of the pendulum in 1822, as it lies as nearly as possible under the Line.
On the following morning, the 25th, the Nemesis crossed the Line, with the thermometer at 96°, which had been the average temperature for several days. Strong adverse winds prevailed, with a heavy swell for many days afterwards, against which she went ahead very steadily, at the rate of five to five and a half knots an hour; but, as it was desirable to save fuel as much as possible, it was at length determined to make a hitherto untried experiment—viz., to work the lee paddle-wheel only, while under sail, (the other wheel being disconnected, and allowed to revolve by the motion of the vessel,) and also to use only one boiler. She was steered about five and a half points from the wind, and in this position, with a rolling sea and steady breeze, she continued to make head at the rate of six and a half to seven knots an hour, the active or lee paddle-wheel making twelve to fifteen revolutions per minute. Thus the success of the trial was complete, particularly as it appeared to counteract the lee-way of the vessel. The helm did not seem to be materially affected by the unequal force applied to the two sides of the vessel.
Some pains have been taken to ascertain whether both engines could be worked to any good purpose with one boiler. In reply to this question, it appears that, except in the river Mersey, at Liverpool, with all circumstances particularly favourable, the Nemesis was never able to work both engines with one boiler with more than very inconsiderable effect. But it must be very evident that any vessel, having power enough to do so in case of emergency, must possess a great advantage; and there is little doubt that, with twenty or thirty horse power more, she would have been able to accomplish it in smooth water, particularly with sails set. It is therefore to be regretted that her power (only one hundred and twenty horse) was scarcely sufficient for her size and weight.
On the 2nd of June, the ship all at once seemed to be lost to the control of the helmsman, and, no other very good reason suggesting itself, the rudder was naturally examined with care. It was at once discovered that the drop or false rudder had been carried away, but by what means did not sufficiently appear, except that, on examination, there was reason to think it must have been fairly worn through at the point of junction with the lower edge of the upper or true rudder—for at this part nearly the whole strain of its action operated.
No time was to be lost in attempting to repair this injury, as the vessel became almost unmanageable, the true rudder, at times, being nearly above water, in the heavy pitching of the ship. With the utmost exertion on the part of the officers and the intelligent carpenter of the ship, a temporary false rudder was constructed, and securely fixed before nightfall. It was, moreover, found to act even better than the original one, having more hold in the water, as well as a larger surface of attachment to the upper rudder. Subjoined is a plan of this contrivance, which will almost suffice to explain its ingenuity. It was made of planks of wood, instead of solid iron, and was secured by chains, in such a manner as to grasp the upper or true rudder firmly, while it could also be raised or lowered at pleasure.
PLAN OF A TEMPORARY RUDDER, FITTED AND SHIPPED AT SEA,
ON BOARD THE H.C. STEAM-VESSEL NEMESIS.
A Main Rudder.
B Side view of temporary rudder, made double, (out of six spare float-boards,) so as to clasp the main rudder on each side.
C Pigs of ballast between the floats, resting on the heel-piece.
D Lower chain guys, which pass round the heel of the rudder, crossing it at the fore part, and leading up on each quarter, with a tackle attached to each side.
E Chain-head guys, passing through bolts in the main rudder, and set up over the stern.
F Strengthening pieces of iron.
The whole apparatus was found to answer remarkably well, and, during the remainder of the voyage to the Cape, (and that a trying one,) it never got out of order, or required additional support. Indeed, it was remarked by every one, that the vessel was more easily steered than it had been before.
But the difficulties which the Nemesis had to encounter were not yet ended. Strong breezes from the southward still prevailed, without any prospect of a speedy change; her progress was slow, and there only remained on board thirty-two tons of coal, with a little wood; nor was there any place at hand to which she could run for fuel. It was therefore resolved to stand out to sea, trusting to her canvas only. Thus her remaining fuel would be reserved for any emergency, and would suffice to ensure her being able to get into port when within a reasonable distance. A reference to the map will shew her position at this time.