Improvements in Manhole Doors applicable to Vessels Carrying Water Ballast and other like Tanks.
Year: 1890

page_text: Date of Application, 6th June, 1890
Complete Specification Left, 27th Feb., 1891-Accepted, 4th Apr., 1891
PROVISIONAL SPECIFICATION,
Improvements in Manhole Doors applicable to Vessels Carrying
Water Ballast and other like Tanks.
I, EDWARD JOBLING, Boiler Maker and Iron Shipbuilder, residing at
59, Hartington Street, Monkwearmonth, in the County of Durban, do hereby
declare the nature of this invention to be as follows :-
The object of my invention is for insuring the greater safety of vessels having
ballast-tanks loaded with water.
My improved manhole door is secured with six screw studs and buttons placed in
such a manner that the force necessary to effectually close the door is evenly distri-
buted all round the edge of the plate."
These six studs are sufficient without the use of cross bars to insure the door
being perfectly water tight.
017
My manhole door is made of plain flat iron oval shaped 19" x 16" x having
six circular holes ths of an inch in diameter evenly pitched round the oval plate
2 inches from the edge. The 2 inches allowed on the edge of the plate being the
Into each of
necessary overlap. The door being fitted on the inside of the tank.
the six holes before mentioned I rivet a screw stud 2 inches in length by ths of
an inch thick.
In addition each stud
is provided with a cast steel notched button. Against this button the screw nut is
tightly pressed when making good at the time of fitting.
Each of these screw studs have screw nuts on the top end.
Round the edge of the plate door I also fit a grummet covered with white lead
or vulcan cement, thereby making the door perfectly water tight when the nuts
attached to the screw studs are well screwed down with a hand spanner.
In the centre of the door I also rivet an iron ring bolt, for the purpose of better
facilitating the handling while taking out and refitting.
My invention and its appliance when completely placed for work has many
advantages over all other articles of this nature hitherto applied. No cross bars
are required, which in other cases have been found clumsy, and difficult to keep in
place, and needing careful attention to prevent serious consequences.
Besides doors with cross bars have only 2 studs rivetted on the middle line
transversely, and are therefore liable to be shifted horizontally, through rough
usage while the vessel is loading.
Any injury sustained by those cross bars and studs render the door useless, and
consequently must endanger the safety of the vessel and cargo, or both, through
leakage.
My invention dispenses with the use of cross bars, gives greater security by
introducing six screw studs instead of two, as in the other case: Any four of my
studs will be sufficient to carry the door safely without leakage.
When my improved manhole door, is placed in position the notched buttons
overlap the edge of the manhole, and when the nuts are properly screwed down,
there is absolute tightness between the plates forming the tank top and that of the
door, making it completely water tight.
Should my door meet with violence while shipping cargo, it cannot shift hori-
zontally through the screw studs being fitted close. to the edge of the manhole.
These studs also assist very materially to strengthen the manhole, and straighten
the edge of the tank top plates all round the hole, the pressure in that case being
evenly distributed. Whereas in the case of cross bars the whole of the force is

page_text: concentrated on 2 studs in the middle line of the plate, giving greater liability to
fracture.
COMPLETE SPECIFICATION.
Improvements in Manhole Doors applicable to Vessels Carrying
Water Ballast and other like Tanks.
I, EDWARD JOBLING, of 59, Hartington Street, Monkwearmouth, in the County
of Durham, Boiler Maker and Iron Ship Builder, do hereby declare the nature of
this invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
My invention relates to improvements in manhole doors applicable to vessels
carrying water ballast and other like tanks, which consists of mechanism for insuring
the greater safety of vessels having ballast tanks loaded with water.
This improved manhole door is secured with six screw studs and buttons placed
in such a manner that the force necessary to effectually close the door is evenly
distributed all round the edge of the plate. The six studs are sufficient without the
use of cross bars to insure the door being perfectly water tight.
And in order that my invention may be thoroughly understood, I now proceed to
describe the accompanying drawings thereof, reference being had to letters and
figures marked thereon. Like letters represent like parts.
Fig. 1 is the plan of the top of the manhole cover fixed to the manhole. The
dotted lines indicate the outline of the manhole cover.
Fig. 2 is a section on line A B of Figure 1 and the hatch.
The manhole door a is constructed of plain flat iron, oval shaped as indicated by
dotted lines in Fig. 1; having six circular holes evenly pitched round the oval
plate near the edge. The margin allowed on the edge of the plate being the
necessary overlap, the door being fitted on the inside of the tank f.
Into each of the six holes before mentioned I rivet a screw stud e of any suitable
size. Each of these screw studs have screw nuts d on the top end; in addition
each stude is provided with a cast steel notched button c. Against this said
button the screw nut is tightly pressed when making good at the time of
fitting.
Rounds of spunyarn with vulcan cement or white lead is laid around the edge of
the door a, and when it is put in position the notched buttons e will overlap the edge
of the tank around the hole; after the nuts d are screwed home, the door a is
perfectly watertight. The studs e assist very materially to strengthen the manhole
and straighten the tank plates around the hole, more so than cross bars. I also
provide an iron ring bolt rivetted into the centre of the door a to facilitate
handling while taking out and refitting.
A manhole cover g with a flush ring in the hatch level i is shewn in section in
Fig. 2, this being no part of my invention.
My invention and its appliances when completely placed for work has many
advantages over all other articles of this nature hitherto applied. No cross bars
are required, which in other cases have been found clumsy and difficult to keep in
place, and needing careful attention to prevent serious consequences. Besides doors
with cross bars have only two studs rivetted on the middle line transversely and are
therefore liable to be shifted horizontally through rough usage while the vessel is
loading. Any injury sustained by those cross bars and studs render the door
useless, and consequently must endanger the safety of the vessel and cargo, or both
through leakage.

page_text: My invention dispenses with the use of cross bars, and I therefore give greater
security by introducing six screw studs e instead of two as in the other hereinbefore
mentioned case. Any four of my studs e will be sufficient to carry the door safely
without leakage.
When the manhole door a is placed in position, the notched buttons c overlap the
edge of the manhole; and when the nuts d are properly screwed down there is
absolutely tightness between the plates forming the tank top fand that of the
door thus making it completely water tight.
a,
Should my invention meet with violence while shipping cargo it cannot shift
horizontally through the screw studs being fitted close to the edge of the manhole ;
these studs e also assist very materially in strengthening the manhole and
straightening the edge of the tank top plates all round the edge of the hole, the
pressure in that case being evenly distributed. Whereas in the case of cross bars
the whole of the force is concentrated on two studs in the middle line of the plate,
causing greater liability to fracture.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination of a manhole cover and six screw studs, with six notched
buttons and nuts fixed to the manhole of a tank to contain water ballast and the
like, substantially as herein described and according to the accompanying
drawings.
2. The combination of the manhole door applicable to vessels carrying water
ballast and other like tanks, substantially as herein described and for the purpose
set forth.
Dated this 27th day of February 1891.
J. P. BAYLY,
18, Fulham Place, W., Agent for the Applicant.