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51
The largest capacity fumigated on any one ship was 540,000 cubic feet. Two of
the fumigations were directed against ascertained plague epizootics, and the remainder
were disinfections on ships which had carried troops or for the destruction of rodents
on non-infected ships.
In the early part of the year the engine bedplate was found to be split, and was
repaired at a cost of 9l. 15s. The barge in which this engine is fitted is old, but in war
time it was deemed expedient to repair the decks and put in stiffening beams rather
than attempt replacement. In dry dock she has been found to be sound below the
water line.
A new bedplate was ordered, but is held over until required.
LAUNCHES.
"Lady Truscott."—On the 13th March, when the cover from the manhole in the
top drum of the boiler was being removed, an explosion occurred breaking the engine
room skylight, and burning the men engaged about the face, neck and hands,
fortunately not seriously. An inspection of the boiler was made by your Consulting
Engineers. They reported that nothing detrimental to the boiler had occurred. The
drum was free from scale and clean, and exception could not be taken to the tubes or
the lower headers.
A test by hydraulic pressure was recommended and applied to the boiler, disclosing
no defect.
The cause of this explosion is one of some rarity. Zinc blocks are used in the
boiler to prevent scaling.
The water of Gravesend town, which is used in the boiler, contains considerable
"hardness," rendering electrolysis possible at a low voltage.
The launch having been laid by, hydrogen had therefore accumulated in the
proportions necessary to form a highly explosive admixture with air. The intense
heat of the hydrogen flame, though momentary, produced painful burns, and the
Engineer, J. A. Hardman, is to be commended for pluckily remaining on duty.
During the year this launch has been kept available for special duties when
required, but from shortage of fuel and hands has not been in general service. These
conditions continue at the date of closing this Report.
During March, new zinc plates were fitted on the quarter of this launch, protecting
the steel plating from electrolytic wasting, at a cost of 5l. 12s. 6d.
"David Burnett."—The repair of the damage caused by fire in fore cabin during
December, 1916, was carried out in March, 1917, at a cost of 2001. In the course of
this work the deck was exposed and found to be damaged. This was repaired at a
further cost of 48l 15s. The whole of this damage was covered by insurance.
Advantage was taken of the occasion to fit the new funnel, which had been
sanctioned.
The boiler of the "David Burnett," which had been leaking at one of the seams,
was repaired in February and March. The weak seam was built up by the electric
welding process, and has not given further trouble.