FIELD OF INVENTION
The present invention relates to an arrangement of fixing of plates on skid during
block fabrication in ship. More particularly, the present invention relates with modification
of regular skid which helps to retain the actual shape of the block (all ships which are built
are divided into small parts called blocks).
BACKGROUND ART
Ships are divided into small parts called blocks. The blocks are built in the shop floor
or in a place with good crane handling facility in the ground. The blocks when finished are
then lifted and taken to the erection site where they undergo joining with the rest of the
blocks of the ship. The joining of all the blocks lead to the completion of the ship and the
ship is launched as a finished product.
All blocks which are built are built on skid. This skid helps to retain the actual shape
of the block. The primary activity going in this process is the laying of plates on the skid.
After that suitable frame, floors, girders and bulkheads are erected into the block.
Finally welding of all these members are done along with the plate lying on the skid.
So the plate forms the visual area of the ship which is viewed from the exterior. The shape is
very important for the performance of the ship.
Till date the plates are fixed permanently to the skid profiles with help of either bolts
or small metal pieces. These are welded to the plate fully using overhead welding. Welding of
bolts hence reduce the strength of the bolt which eventually lead to breaking of bolts when
welding is going on in the block as welding leads to a lot of contraction and expansion of

these plates. Flat bars welded to the plate do not allow expansion and contraction of the
plate thus allowing much distortion to occur in the plates which in turn affects the aesthetics
of the outer hull and affects the performance of the ship. Figure 1 shows the flow diagram
showing use of bolts to fix plates on the skid.
DEFECTS IN PRIOR ART
The following are the negative impacts which the conventional system has:
HIGH PRODUCTION TIME
HIGH INEFFECTIVE TIME DUE TO INVOLVMENT OF OVERHEAD FITTING
AND WELDING OF BOLTS
LOSS OF STRENGTH OF BOLTS DUE TO HEAT INPUT FROM WELDING
DIFFICULTY TO RE FIX THE PLATE WHEN THE BOLT BREAKS OFF.
A LOT OF HEAT INPUT WHILE GOUGING THE BROKEN PART OF BOLT
FROM PLATE.
OBJECT OF INVENTION
During initial stages of block fabrication we need to fix the plates to precede with the
block fabrication activities. Traditionally the process involves lot of overhead work beneath
the plate by skilled and unskilled workers. The process is slow and involves lot of redundant
manpower.
The object of this invention is to simplify the work by removing all overhead work,
avoiding breaking of bolts, allowing expansion and contraction of plates during welding,
avoid distortion to plate and finally improve the quality of finished product.

In addition it vastly increases the safety of workers who previously had to work
underneath the plates in constricted spaces.
Hence, the challenge to design, develop, test and successfully implement this
arrangement of fixing of plates on skid so that the block retains its shape properly and
has good aesthetic value in the finished product.
SUMMARY OF INVENTION
Therefore such as herein described, there is provided A method for plate fixation
arrangement (fabrication) on skid which make the outer hull of the ship comprising the
steps like : at first the channels are tack welded to plate on ground in desired locations.
Then angles are tack welded in the same location but with the skid. The plate fitted with
channel is then overturned on the skid fitted with angles. Then nut bolts are used to pass
through groves cut in the channels and angles and they are tightened. The plate is thus
rigidly fixed to the skid allowing only movement due to welding and restricting all other
motion.
BRIEF DESCRIPTION WITH ACCOMPANYING DRAWINGS
Fig. 1 shows the use of bolts which are directly welded to the plate and use of nuts
to tighten the bolt and fix the plate on the skid in accordance with the present invention;
Fig.2 shows describes the flow chart wherein channels and angles are used along
with nut and bolts to fix the plate on the skid in accordance with the present invention.

DETAILED DESCRIPTION
To understand the conventional method of plate fixing we have to have a fair good
knowledge of what a skid is and why it is used for fabrication of blocks of the ship.
A skid is a skeletal structure which determines the outer shape of a block of a ship.
Plates which make the outer hull of the ship are given the shape of the skid and then fixed
on the skid profiles to retain its shape at the end of the block fabrication procedure. During
block fabrication there is a vast application of welding process.
What welding does is it changes the dimensions and shape of the plates. Here the
skid is necessary for retaining the shape of the block during welding. But we must allow
some movement due to expansion and contraction due to large heat inputs due to welding of
the plates in order to avoid distortion. So the plates need to have some movement due to
welding, but no other movement of plate is allowed all throughout the fabrication process. If
we have a look at the existing process where bolts are welded to the plate, the bolts break off
during fabrication. Repair work has to be performed in between. This allows distortion
process to occur in the block, rectification of which destroys the quality of the job. If we look
at the pictorial representation we will get a clear idea of the process.
The innovation improves the plate fixing process and eliminates any rectification
process during block fabrication. Let us look at the pictorial representation first and then we
shall see step by step the new process going on.
In the new process we first put reference marking on the plate which is overturned.
We then fix channels with groves cut in them in the desired locations. Then according to the
same markings on the plate we take reference markings on the skid profile and fit angles

with grooves cut in them in the marked locations. We then overturn the plate and match the
channels sitting above the angles. A pictorial flow chart as shown in Fig.2, shows the
modified method of plate fixation on skid.
The bolt of required size is then passed through the channel and angle and it is
tightened with appropriate nut. Tightening of the nut leads to the fixing of the plate firmly in
the skid.
This arrangement allows movement of the plate only in two directions which can only
come during welding of the block. Thus after welding also we easily avoid distortions and we
maintain the aesthetic value of the block.
ADVANTAGES AND USES OF PRESENT INVENTION
The invention has allowed us to eliminate a lot of problems which were occurring in
the existing process. Now we have completely removed overhead welding work for plate
fixation. This in turn has reduced the working hours for the same job by almost 40%. We
have prevented breaking of bolts thus has helped the block to retain its shape at all times
without any distortion occurring to it. Finally we have improved the aesthetic value of the
ship as a whole and have also kept intact the performance of the ship.
The present invention has a wide range of Industrial application both for naval ship
and merchant vessel construction. This system of cleaning of black water from bilge area of
ship will reduce the overall cleaning time and improve the safety of work.

INVENTIVE STEP
1. Process of execution of fixing of plates in skid during block fabrication
process in ship building industry using channels, angles and bolts.
2. Process of construction of plate fixing arrangement in skid during block
fabrication process in shipbuilding.
3. Process of construction of plate fixing arrangement with the process of
reducing distortion in welding.
4. Design and process of construction of plate fixing arrangement with the
process of improving aesthetic value of the ship.
Although the foregoing description of the present invention has been shown and
described with reference to particular embodiments and applications thereof, it has been
presented for purposes of illustration by way of examples and description and is not
intended to be exhaustive or to limit the invention to the particular embodiments and
applications disclosed. The particular embodiments and applications were chosen and
described to provide the best illustration of the principles of the invention and its practical
application to thereby enable one of ordinary skill in the art to utilize the invention in various
embodiments and with various modifications as are suited to the particular use
contemplated. All such changes, modifications, variations, and alterations should therefore
be seen as being within the scope of the present invention as determined by the appended
claims when interpreted in accordance with the breadth to which they are fairly, legally, and
equitably entitled.

We claim :
1. A method for plate fixation arrangement (fabrication) on skid which make the
outer hull of the ship comprising the steps of:
welding of channels to plate on ground in different locations;
welding of angles with the skid over the said location;
overturning of the plate fitted with channel on the skid fitted with angles;
matching is done such that the said channels sit above the angles; and
passing nut and bolts through groves cut in the channels, angles and are tightened
such that the plate is rigidly fixed to the skid allowing only movement due to welding and
restricting all other motion.
2. The method for plate fixation arrangement as claimed in Claim 1, wherein
tack welding is done for welding of channels and angles.
3. The method for plate fixation arrangement as claimed in Claim 1, wherein the
different locations are present on the skid.
4. The method for plate fixation arrangement as claimed in Claim 1, wherein
marking is done on the plate before it is overturned and these are taken as reference
markings on the skid profile and thereby fitting of angles with grooves cut in them is carried
out in the said marked locations.

5. The method for plate fixation arrangement as claimed in Claim 1, wherein the
said arrangement allows movement of the plate only in two directions which can only come
during welding of the block.
6. The method for plate fixation arrangement as claimed in Claim 1, wherein the
said welding avoid distortions and maintain the aesthetic value of the block FABRICATION.