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Eu anden Methode var at tage Tidsintervaller under
Indhivningen afLodlinen, idet man lod Indhivningsmaskinen
gaa saa jevnt som muligt. Herved tik man bestemt elet
Tidsrum. Maskinen brugte for at tage ind 100 Favne
saavelsom det Tidsrum, den med samme Hastighed tog iud
Overskuddet over sidste Hundredefavnemærke, og Længden
af det sidste kunde saaledes bestemmes ved simpel
Proportion. Med jevnt Damptryk og jevn Damptilførsel til
Maskinen. hvilke er lettere at holde end jevn Bremsning især
i urolig Sø. giver denne Methode gode Resultater. Dens
Resultater antoges, naar den anvendtes med de nævnte
Forudsætninger, som de definitive, forsaavidt ikke den i
det følgende beskrevne Methode kom til ’Anvendelse. De
Lodskud, som i 1876 falde paa Dybderne mellem 100 og
300 Favne, beregnedes udelukkende efter den sidst
beskrevne Methode.
Den tredie Methode, der er den sikreste, indførtes
først i 1877. Idet Loddet løftedes af Bunden, viste
Virkningen af dets Vægt. sig paa Accumulatorer der pludselig
strakte sig noget ud. En Mand. som stod klar ved
agterste Spiltap. greb i dette Øjeblik paa givet Signal med den
ene Haand om halende Part af Linen over Midten af
Tappen. og fulgte med Linen, idet denne rulledes op paa
Rullen. agterover en paa Dækket afsat Længde af 3 Favne.
Naar han kom til agterste Mærke, slåp han Linen og raabte
„En". Næste Mand greb da fat om Linen ved Tappen,
og naar han kom til agterste Mærke, raabte han ..To" o.s.v.
Idet det sidst udløbne Hundredefavnemærke kom i
Vandskorpen varskoedes „Stop’. Den søgte Længde af Lodlinen
fandtes saaledes ved direkte l’dmaaimg med eii
Nøjagtighed af en Brøkdel af en Favn.
Ved de mindste Dybder, for hvilke Lodlinen var
mærket for hver 10de Favn, bestemtes det enkelte Favnetal i
Regelen ved direkte Udmaaling, dels alene, dels som
Control for Tidsintervaller med Indhivningsmaskinen.
Lodning med BaiUie-Maskinen. Denne blev gjort i
Stand paa Agterdækket lige agtenfor Hytten som før
forklaret. Saasnart de nødvendige Forberedelser med
Lodlinen og Accumulatorer de samme som ovenfor beskrevne,
var færdig, hexedes Lodlinen til Bingen i ßaillie-Maskinen
eller til øverste Øjebolt i Vandhenteren og i dette ,Tilfælde
nederste Øjebolt i Vandhenteren til Ringen paa Roret.
Linen stivhaltes og lagdes rundt Tapperne paa
Indhivningsmaskinen. Med denne løftedes nu, naar Fartøjet var stoppet,
det hele over Rækken mellem Hytten og Storvantet (Fig.
14) og firedes ned i Vandet for ikke at komme i Svingning
og Berøring med Skibssiden under Fartøjets Bevægelser.
Dybvandsthermometrene fastgjordes derefter paa Linen 11 å
2 Favne over Vandhenteren eller Lodderne, hvorpaa man
med Indhivningsmaskinen udfirede raskt 200 eller 300 Favne.
Maskinen standsedes, Stopper paasattes i Forhaand paa
Hyttedækket, Linen kastedes af Spiltapperne og rulledes
from computation by time-intervals almost always proved
too high.
Another method practised was to measure
time-intervals during the winding in of the line, due care being
taken to regulate with the greatest nicety the working of
the donkey-engine. We could thus determine both the
time required for bringing in 100 fathoms and that needed
for hauling in the surplus portion of the line run out
after the last 100 fathom slip had reached the water, the
length of which was then computed by simple proportion.
With an equable steam pressure and an equable supply of
steam, which is much easier to keep up, more especially
in a rough sea. than uniform manual braking, this method
will give good results: and hence,’when carefully obtained,
we regarded such as final, save when the method described
below was also had recourse to. The soundings taken in
1876 that embrace depths from 100 to 300 fathoms, were
computed exclusively by this method.
The third method, which is the most trustworthy, was
not adopted till 1877. On the lead being lifted from the
bottom, its weight tells upon the accumulator, which
instantly yields a little to the strain. Then, at a given
signal. a man, stationed for the purpose at the after drum
of the donkey-engine, laid hold of the line as near as may
be above the middle of the drum, and while the leading
part was being wound on the reel, went aft with it for a
distance of 3 fathoms, which had been marked off on the
deck, and thereupon let go, calling out as lie did so —
,.One"! Another man then caught hold of the line above
the drum, went the same distance aft. and cried — „Two"’!
and so on in like manner. The instant the 100 fathom
slip last run out appeared above the surface of the water,
a man called out — ,. Stop"! Thus, by actual measurement,
we found the length of the line within a fraction of a
fathom.
Soundings in shallower water, for which the line was
graduated into tens of fathoms, we generally determined
by direct measurement, whether taken as independent
operations or as a means to test the accuracy of the
time-intervals registered when heaving in the lead.
Sounding ivitli the Baillie Machine. — As previously
stated, this instrument was got ready for use on the
after-deck. just abaft the roundhouse. After arranging, in the
manner described above, the sounding-line and the
accumulator. we shackled the former either to the ring of the
Baillie machine or to the upper eye-bolt of the
water-bottle. the lower eye-bolt being in the latter case attached
to the ring of the tube. The line was now hauled taut
and passed round the drums of the donkey-engine. Then,
having deadened the ship’s way, we hoisted, by means ot
the donkey-engine, the whole of the gear over the railing,
between the roundhouse and the main shrouds (Fig. 14).
and lowered it into the water, to prevent the machine from
oscillating and from bumping against the side of the
vessel. The deep-sea thermometers were next made fast to
the line. 1 or 2 fathoms above the water-bottle or the
weight, after which we rapidly veered 200 or 300 fathoms
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