THE HONGKONG GOVERNMENT GAZETTE, 5тu APRIL, 1884.
281
On the 22nd February, steam was again raised and a trial made; when the Government Marine Surveyor was not present, he not having been notified.
On the 24th February, steam was raised, and the vessel proceeded on a trip to Macao to resume her duties on the Canton and Macao line. The Government Marine Surveyor and others were on board.
The boilers primed soon after starting and it is our opinion that the stop-valve on the starboard boiler was partially closed to check the priming, and was not again opened; the effect being that the steam generated in the boiler was in excess of that passing away to the engines, and gradually accu- mulated. This in itself would not have caused the bursting of the boiler, inasmuch as the safety- valves should have lifted, and relieved it of any excess of pressure.
Under the impression that the spring was broken, and to prevent the steam blowing off, the Government safety-valve of the starboard boiler, which had not been previously adjusted, was shored down, with the knowledge and approval of the Government Marine Surveyor, shortly after which this boiler exploded.
If it was considered advisable to shore down the locked-up safety-valve, the working-valve should previously have been tried by hand, and proved to be efficient and working freely in its scat.
There is no evidence to show that this was done.
We are of opinion that nothing can justify the shoring down of a safety-valve, that is, fixing the valve immovably in its scat.
On the assumption that the spring was broken, the following was the proper course to pursue:- a. A weight put on the vertical rod on the valve to keep it in its seat; the weight to be such as to allow the valve to lift before the normal weighted pressure was much exceeded, or, b. A rough lever of wood might have been arranged, fixed at one end, and so weighted at the
other as to cause the valve to act as described in the preceding paragraph, or,
c. If it were not practicable to weight the valve as described in paragraphs a and b, the fires in that boiler should have been drawn, the boiler disconnected and the vessel steamed slowly into Port with the remaining boiler.
8. In view of the foregoing, we consider that the Government Mariuc Surveyor made a very grave error of judgement in approving of the shoring down of the Government safety-valve. He doubtless depended on the working safety-valve lifting, and relieving any excess of pressure. But we are of opinion that this valve was also fixed in its seat, because it failed to relieve the boiler of the excessive pressure which caused the explosion.
With a view to preventing in future an explosion such as that which occurred on board the Yot-sai, we make the following recommendations:-
That in the case of all newly constructed boilers, or boilers which have undergone repairs, it shall be compulsory on the Owners, Agents or Master to cause the following precautions to be observed:-- 1. That after the completion of the repairs, an examination of the safety-valves and their fittings
be made by a competent Engineer.
2. That this Engineer shall adjust the weight on all the safety-valves the first time sten is raised
in the boilers, and before the vessel proceeds under steam.
3. That he examine the boiler steam gauges, with a view to ensuring that they are in good order, placed in a conspicuous position, and that their pipes are connected to the steam space of the boiler.
If the boilers are for a vessel for which a Passenger Certificate is required, the Government Marine Surveyor is the proper person to perform the duties described, and he should supply the Owners, Agents or Master with a Certificate to the effect that the vessel may proceed under steain.
If these recommendations are carried out, we are satisfied that it will be impossible for a boiler to explode from excessive pressure.
Given under our hands at Hongkong, this 26th day of March, 1884.
H. G. THOMSETT, R.N., Stipendiary Magistrate.
HARRY WILLIAMS, Chief Inspector of Machinery, R.N. JAS. R. TWENTYMAN, First Class Engineer, Mercantile
Marine.
Approved,
G. F. BOWEN, Governor and Commander-in-Chief.
No comments yet.
Private notes are available after approval.