Myanmar Defence Forum

[tarpitz]

Rome is not built in a day.
Step by step development of locally built navy ships of Myanmar.

 

[tarpitz]

Good looking ship. But you guys need better welder and welding rod. New ship but looks beaten up. Rust will be a big problem in the badly welded areas.

I know the feeling of "Sour Grapes".
These are some photos of welding of Chinese and other ships.

Myanmar is thinking of sending her naval engineers to BD to learn how to make ships out of junk. After returning from BD, they will be able to build more decent ships.

 

[Stag112]

lol point me out where did we weld very bad.. it is just a very ok condition for sea going war ships which was operated for years. as ur logic , seem Singapore need better welders and welding rods too.? actually Singapore should send their engineers to BD to learn how to weld and build a war ship before building of their own. lol

formiddable class of Singapore navy
View attachment 389228

The uneven surface is meant to reduce the maximum RCS the ship offers.

In other words a perfectly even surface at a certain relative angle will offer a much stronger radar signature compared to a slightly uneven one. Meaning at all other relative angles, the uneven surface will return a slighly stronger signature, but it will be so weak anyway that there should be no material risk.

 

[TopCat]

lol point me out where did we weld very bad.. it is just a very ok condition for sea going war ships which was operated for years. as ur logic , seem Singapore need better welders and welding rods too.? actually Singapore should send their engineers to BD to learn how to weld and build a war ship before building of their own. lol

formiddable class of Singapore navy
View attachment 389228

I dont think this is singapores flag ship unlike yours. The rust shown in the surface is due to the bad welding.. you can see it yourself.

The uneven surface is meant to reduce the maximum RCS the ship offers.

In other words a perfectly even surface at a certain relative angle will offer a much stronger radar signature compared to a slightly uneven one. Meaning at all other relative angles, the uneven surface will return a slighly stronger signature, but it will be so weak anyway that there should be no material risk.

Actually the uneven shapes are probably due to absense of good Machine Presses which are very expensive to procure. Most of the cheap ship buildings only involved cutting, hammering and welding.
I am not sure about mm though.

 

[Stag112]

I dont think this is singapores flag ship unlike yours. The rust shown in the surface is due to the bad welding.. you can see it yourself.


Actually the uneven shapes are probably due to absense of good Machine Presses which are very expensive to procure. Most of the cheap ship buildings only involved cutting, hammering and welding.
I am not sure about mm though.

This is NOT Bangladesh section where you are entitled to your facts. I gave you an explanation that is a fact. You can look it up if you care. ALL stealth ships have this feature. I do not think billion dollar ships are exactly CHEAP. I understand you have you differences with your neighbors, but dont be unreasonable and weird at all times. Its very immature.

 

[barjo]

So much heartburn from the low IQ being exposed:

Silly twerp doesn't even realise the effect of camera angles and lighting.



Obviously!

Some effect of sun light from the ocean water uneven or ripple surface make dark and bright siluet on ship hull so it sometime makes ship hull seems pocky.. but its all eyes trick from hot weather...

cmiiw

 

[Nilgiri]

In the mean time:

In designing a ship with reduced radar signature, the main concerns are radar beams originating near or slightly above the horizon (as seen from the ship) coming from distant patrol aircraft, other ships or sea-skimming anti-ship missiles with active radar seekers. Therefore, the shape of the ship avoids vertical surfaces, which would perfectly reflect any such beams directly back to the emitter. Retro-reflective right angles are eliminated to avoid causing the cat's eye effect. A stealthy ship shape can be achieved by constructing the hull and superstructure with a series of slightly protruding and retruding surfaces.

https://www.revolvy.com/topic/Stealth ship&item_type=topic

Reeds Vol 14: Stealth Warship Technology

 

[Nilgiri]

The burmese guy removed the one of the picture in question. So I cant refer it back. You are pointing towards even geometrical protruding on the hull but this is not the case in the following picture. I may be wrong whether its intentional.

Induced thermal stresses (from the inherent geometrical protusion) and camera lighting/contrast can create this visual effect.

If you look up enough pictures of any stealth warship, you will find a cpl pictures like this (hence that pic of DDG-1000 I posted earlier too).

Here is same ship under different lighting:

 

[Penguin]

@Penguin @Bilal9
Brother could give us your expert opinion as to why Myanmar and some other navy (shown here by knowledgeable posters) have all beaten up hulls. Is it due to super stealthy feature or for bad workmanship. I am just totally confused. I tried to look up but could not find this advance feature in some of the most expensive ships like DDG-1000.
Your opinion is highly appreciated.

Define 'beaten up"

Dutch LCF (Zeven Provincien)

 

[TopCat]

Define 'beaten up"

Dutch LCF (Zeven Provincien)

 

[Penguin]

RSS Intrepid, a Formidable class frigate of the Singaporean Navy

491, a 49m FAC-M of the Myanmar Navy

@TopCat

I suppose metal hullplating "works" a bit with temperature changes. Also, I imagine a ship is not (nor should it be!) fully 100% rigid and so the hull also "works" (it flexes along three axes, sometimes to the point of developing cracks).

"A ship may be made of steel, but it must be assembled in such a way that there is built in elasticity to cope with the huge forces of the sea that will flex the whole ship, subject it to huge weights and pressures, and threaten, if it were not well designed, to tear the ship apart."
http://njscuba.net/artifacts/obj_hull_steel.php

It may be that ships with hull and superstructure shaping for RCS reduction, which often leads to large flat surfaces at a greater or lesser angle from vertical, are prone to more visible 'buckling' of the hullplates (not necessarily more buckling per se, just more evident)

Those are jst some layman ideas of mine on this topic. Researching the phenomenon might turn up more or better explanations.

RSS Steadfast

 

[TopCat]

RSS Intrepid, a Formidable class frigate of the Singaporean Navy

491, a 49m FAC-M of the Myanmar Navy

@TopCat

I suppose metal hullplating "works" a bit with temperature changes. Also, I imagine a ship is not (nor should it be!) fully 100% rigid and so the hull also "works" (it flexes along three axes, sometimes to the point of developing cracks).

"A ship may be made of steel, but it must be assembled in such a way that there is built in elasticity to cope with the huge forces of the sea that will flex the whole ship, subject it to huge weights and pressures, and threaten, if it were not well designed, to tear the ship apart."
http://njscuba.net/artifacts/obj_hull_steel.php


RSS Steadfast

RSS Intrepid, a Formidable class frigate of the Singaporean Navy

491, a 49m FAC-M of the Myanmar Navy

@TopCat

I suppose metal hullplating "works" a bit with temperature changes. Also, I imagine a ship is not (nor should it be!) fully 100% rigid and so the hull also "works" (it flexes along three axes, sometimes to the point of developing cracks).

"A ship may be made of steel, but it must be assembled in such a way that there is built in elasticity to cope with the huge forces of the sea that will flex the whole ship, subject it to huge weights and pressures, and threaten, if it were not well designed, to tear the ship apart."
http://njscuba.net/artifacts/obj_hull_steel.php

It may be that ships with hull and superstructure shaping for RCS reduction, which often leads to large flat surfaces at a greater or lesser angle from vertical, are prone to more visible 'buckling' of the hullplates (not necessarily more buckling per se, just more evident)

Those are jst some layman ideas of mine on this topic. Researching the phenomenon might turn up more or better explanations.

RSS Steadfast

That make sense.
So they were not for stealthy feature but for stress related bending.
What does it meant for a welding mark visible for a hull with bare eyes? Does a very good shipbuilding yard take special care for welding quality in addition to uninterrupted welding? How machine press can be used to reduce the number of weld required as well as overall quality of the design and fabrication?

 

[Penguin]

That make sense.
So they were not for stealthy feature but for stress related bending.
What does it meant for a welding mark visible for a hull with bare eyes? Does a very good shipbuilding yard take special care for welding quality in addition to uninterrupted welding? How machine press can be used to reduce the number of weld required as well as overall quality of the design and fabrication?

No, that is not what I said.
I said the buckling may be a result of hull flexing and this may be more evident in ships with stealth features (i.e. with large, smooth surfaces). I'm not the best person to answer your questions concerning shipbuilding specifics. Perhaps others with more experience and knowledge in design and construction can jump in?

 

[Penguin]

It is not a new phenomenon.

Allen M. Sumner FRAM II class destroyer

 

[TopCat]

4.3. WELDING INDUCED DEFORMATION
As in case of the stresses occurring during and after welding, welding deformation can be transient or residual. Figure 7 gives an overview of various types of welding deformations to be expected when welding plates.


FIGURE 7.
Different types of welding distortions. The arrows indicate the shrinkage direction of the weld metal which causes the corresponding distortion [Masubuchi 1980].

All these kinds of distortions are related to the shrinkage of the weld metal during cooling. They can be subdivided into:

Figure 8). Such problem results through various stages of production have emerged as a major obstacle to the cost-effective fabrication of lightweight structures. Same situation may occurs in aerospace and aircraft assembly where the high strength to weight ratio are necessary and thin elements are used, in addition to the requirement of smooth surface to maximize hydrodynamic performance and minimize radar signature [Huang 2004]. A conservative estimation for the labor costs accumulating for post-welding distortion correction is approximately 30 % [Andersen 2000; van der Aa,2007].

Here is your answer @Penguin @Bilal9
Culprit is welding. It has nothing to do with stealth.