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A seafarer may not be involved in the ship construction so much. But that does non hateful that they demand non know anything about it. For example if you see a crack in ballast tank, you should exist able to tell exactly where the crack is.

It is only possible if you lot can identify the structures within the anchor tank. Same applies to the other parts of the ship too.

Nosotros read about ship construction during our competency exams. Just problem is ship construction topics starts from the medium level and not from the basic level.

For example if we demand to draw the construction of double bottom, learning just involves placing each component at its place without answering why.

The get-go step of studying the ship construction demand to be knowing about the basic terms of transport constructions.

In this post I will discuss and explain x basic terms used in ship construction.

But before nosotros do that, starting time lets discuss briefly what ship is made of.

What are ships fabricated of

Ships are made of steel and we all know that. Simply what all forms of steel are used in building ships. I mean what shape of steel ?

Earlier learning anything about send structure we need to know the shapes used in ship construction. Allow u.s.a. discuss few of these.

Plate

Nosotros all know what we mean by plate. It is a rectangular shape steel with certain thickness. The almost common identify you can see the plate in ship construction is the main deck and side of the ship.

Bar

There is only one principle difference between steel plate and steel bar. The steel bar has bottom cross exclusive width than the steel plate.

This tabular array gives a off-white idea what cantankerous department of a steel tin exist called a plate/sheet or a bar.

Axle

A beam is a structural element that increases load bearing capability and avert bending of the construction. Beams tin exist categorized by many types simply from point of ship construction, we need to categorize information technology through cantankerous sectional shape.

For example, in that location are L-Shaped beams, C-shaped beams, I-shaped beams and SI-shaped beams. SI shaped beams are I-shaped beams with slight curved cantankerous department.

Shape of the beams are not limited to these ones. It can be in many other shapes.

At present that we know the shapes and structure of the steel used in ship construction, we can discuss the ship construction terms. But nosotros take to understand that all these construction volition be a form of plate, bar or axle.

i. Keel

First thing first. When nosotros say "Keel of the ship", nosotros are referring to a steel plate. Though it can likewise exist in the course of steel bar but it is very rare these days.

Keel of the ship is the bottom most plate of the send laid forth the entire length of the ship.

During structure of the send this is the first thing that is placed on the blocks. Because of this, laying the keep is considered to be the fourth dimension when construction of the ship begins.

Keel laying also has the importance with respect to many IMO conventions as this is the date construction of the transport starts.

Then keel is the steel plate with slightly more than thickness than the other adjoining plates on its sides. This area need more strengthening because the ship sits on this area on the blocks, during construction as well as during dry docks.

We tin can consider the keel of the ship every bit the backbone or spine of the ship.

Years back keel laying involved actually laying the keel of the ship on the blocks. Run into beneath the keel of the titanic being laid.

Present keel laying is considered to be the time when first piece of the ship structure is placed on the the wooden blocks. Like run into below the keel laying of cruise send "Anthem of the seas".

2. Shell plating

Again when we say vanquish plating, nosotros are referring to a steel plate. In this case information technology is too obvious from the name.

Shell plating is the steel plate used on the shell of the ship. The dictionary meaning of the shell is "hard outer covering". Then shell plating is any we see on outer side of the transport.

1 of the chief purpose of crush plating is to provide watertight peel of the ship. Apart from that it also adds to the longitudinal force of the ship.

Send construction requires us to exist able to pin point each component. So when we say vanquish plating, it is a huge area. We can farther split up this area in two broad parts, which is

• Bottom trounce plating
• Side shell plating

I am and so much sure that yous already would know what these two terms mean.

Bottom trounce plating is the shell plating on the lesser part of the send. Or we tin tin that bottom beat plating course the watertight skin of the lesser of the transport. It is the plate laid in the horizontal direction.

To a certain extent nosotros tin can say that even keel of the transport is also lesser shell plate.

Side shell plating is the shell plating on the sides of the send that forms the watertight peel along the ship side. It is the plate laid in the vertical direction.

3. Deck plating

This is ane is too obvious. Deck plating once again is a plate. Information technology is steel plate that forms the main deck of the ship.

As per the location, nosotros can requite a more specific name to the deck plating. For case accommodation deck plating or primary deck plating.

four. Strake

To understand what strake is, we need to again understand the construction of shell plating.

I am dead sure y'all know that transport's side plate (Trounce plating) is not made of single metal sheet. It is made of smaller sections of steel plates. These smaller sections of the plate are welded together.

In quondam days these were riveted instead of welding.

Irrespective of with what method these plates are joined together, these are placed in a certain design.

Let us empathise this with an example of box shaped ship. The smaller plates that we are talking well-nigh would look something like this for the box shaped ship.

In naval architecture and ship construction each of these plate has an identification. These are numbered in sure pattern. For example the plates on the side shell plating are numbered similar this.

• The plates are identified by a letter and a number
• Each plate is given a letter in the vertical direction starting with A from the bottom.
• Each plate is given a number in the horizontal management starting from aft.

Now based on these numbering system the identification of plates for the box shaped ship would look something like this.

Each section of the plate placed in fore and aft management is called a "strake".

And so in the above example, we take A-Strake, B-Strake and then on.

If nosotros desire to be more specific, We tin can say that nosotros have starboard A-Strake , starboard B-strake and so on. Like naming will be on the port side.

For the lesser trounce plating, like numbering is done for the plates forming it. For the bottom shell plating

• Plates are given a alphabetic character starting with "A" to the plate next to the keel plate.
• Plates and given a number starting from the aft

So the plate adjacent to the keel plate will take a identification of A1, A2 and so on starting with A1 from the afterward most plate.

Now in that location are 3 type of strakes that you would hear in send construction. Let us run into what these are.

Shear Strake

Shear strake is the superlative most strake of the Side shell plating. So if side beat out plating has strakes from A to One thousand, then 1000-strake is the shear strake. This is the strake that connects with the deck plating.

Can yous identify the shear strake in the box shape send example that i gave above ? Yes, you lot got it right. I-Strake is the shear strake in this case.

Shear strake is unremarkably of higher thickness and strength than other strakes. This is because this strake tin have lot of concrete damages during the life of send.

Keel Strake

I earlier said that keel is a plate that is dorsum bone of the ship. But keel plate is also made upward of smaller sections of the steel plates. These strake of plates that form the keel of the transport is called Keel Strake.

The plates in the keel strake are number from aft to forward starting from the aft 1 which has the number "i".

Unlike other strakes, keel strakes practice not take letter associated with its naming.

Garboard Strake

Garboard strake is the get-go strake on each side of the keel strake. Every bit we discussed in the bottom strakes, the first pale from the keel is named A-strake.

So we can also say that Bottom A-strake is chosen Garboard strake.

Now for the box shape transport, the naming of strakes might wait simple only for actual send with curved sides and flared bottom, information technology might not be that simple.

The naming and structure of side and lesser shell plating is provided in the "Shell expansion plan".

Side by side fourth dimension y'all become your hands on a shell expansion program of your transport, effort to read it to place shear strake, keel strake and garboard strake.

So beneath moving picture shows how beat plating and Strakes are continued with each other.

5. Stiffners

A steel plate of 2mm thickness can be hands bent. If you lot elevator this plate with the crane from its ends, it will most likely bend at the centre. At present what tin y'all do to avoid it from bending ?

One like shooting fish in a barrel solution is to increment the thickness of the plate past welding ii or more than plates together. But in transport construction this is non a good idea. I among many reasons for this is that we exercise not want to increment the light weight of the ship.

The better choice is to weld two of more than flat confined either in fore and aft direction or athwartship direction.

In this case these flat bars will be called stiffners. Anything that is used solely to provide strength to a transport structure can exist chosen a stiffner.

A stiffner welded in longitudinal direction is called "Longitudinal stiffner". Same way a stiffners welded in transverse direction is just called "transverse stiffner".

Longitudinal stiffners and transverse stiffners can farther will named according to various factors including the amount of strength these provide to the structure.

Allow us discuss few of these.

6. Girder

Girders are i form of longitudinal stiffners. These are

• Big size steel plate (or sometimes beams) connected to bottom of the transport
• Runs in fore and aft direction
• strengthen the send against bending moment

Girders are also named according to its location. The girder at the center of the ship is called center girder.

In double bottom tanks, the thick solid metallic plate that divides the ballast tanks into port and starboard tank is the middle girder.

Apart from the center girder, there can be few girders on each side of the ship or double bottom.

Depending upon the breadth of the ship, there tin can exist more than 1 side girder on each side.

While center girder runs in full depth of the double bottom tank, side girders may or may not run in total depth.

Though beneath photograph is non that of a ship, it is practiced representation of a ship's strengthening components. If you meet in this case girder is farther strengthened with something we may call "Vertical Stiffners" every bit at that place is no other specific name for it.

7. Longitudinals

Longitudinal is short proper name for longitudinal stiffners.

In almost cases the longitudinals are beams (mostly 50-beams) and runs forth the length of the send. Double bottom space is the most common space where yous can easliy identify longitudinals.

Longitudinals are further named depending upon what department these longitudinals are strengthening.

In double bottom anchor tank, longitudinals strengthening the bottom are chosen "bottom longitudinals". Longitudinals strenghtening the top of the ballast tank are called "top longitudinals".

If you have been to a double bottom tank, these longitudinals are difficult to miss. The lesser longitudinals are the one nosotros sometime step on to avoid stepping in the left over water (or mud) of the anchor tank.

I am sure you tin locate the longitudinals in above picture that I shared. If you cannot, I share it again with marking of longitudinals.

eight. Frames

Frames act every bit major transverse stiffners. Frames are

• Big size steel plate connected to bottom of the ship
• Runs in athwartship direction
• strengthen the ship against buckling and angle.

Nosotros tin can consider the frames to be like to the girders merely with just 1 difference. Frames runs in transverse (Athwartship) direction.

If keel is the backbone of the ship, the frames are considered to be the rib muzzle.

Frames are numbered starting from aft perpendiculars.

9. Transverse

Transverse is the brusk proper name for "transverse stiffners". These are different from frames in two ways. First unlike frames these do non extend to full top of the compartment. 2nd transverse are of lesser strength and thickness than frames.

Based on the location of transverse, these may exist called "bottom transverse", "inner bottom transverse" or even "deck transverse".

10. Stringers

In the in a higher place photo, observe how the girder is stiffned. The stiffner is welded in vertical direction. If same stiffner is required to exist welded in horizontal direction, information technology will be called stringer.

One of the location where stringer is more often than not used is the forwards part of the ship. Bow of the ship has to deport lots of stress so requires extra strengthening.

I will limit myself with discussion of bow construction just to understand stringers. I will cover bow construction in detail some other 24-hour interval.

And so amidst many other strengthening members, panting beams are used in this surface area to counter these stresses.

But even these beams need to be stiffened at the point where these connects with the side frame. Panting stringers does this job. As I said stringers are horizontal stiffeners (parallel to the water line).

Conclusion

Ship construction is something that requires a lot of imagination to understand. But even if someone has a potent imagination bone in the body, knowledge of send construction will still be difficult without knowing basic terms used in it.

These 10 terms are the basic of ship constructions and once nosotros know these, ship construction will be a piddling easier task.

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Source: https://www.myseatime.com/blog/detail/10-simple-terms-to-understand-ship-construction-better

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