Type 075 LHD discussion


Tam

Major
Registered Member
I think its more like they want to hide the ship internals. The line you don't cross is photographing the ship internals. Right now, the other two ships are in a stage being in blocks and pieces that their internals are going to be seen. That's why the ships are pixeled out in the photos and if the first ship reveals whats inside through its rear elevator, that's pixeled out too. When the other two ships are sufficiently formed and covered by a hull that conceals their internals, then they are allowed to be posted in the Internet.
 

winton

New Member
Registered Member
The curved clipper bow on the type 075 is totally unlike those on any other Chinese warship. It suggest to me this ship’s hull is based merchant design, and not warship standard. Whether that is actually so might be shown once we actually see the underwater hull form around the screws and propellers.
How does a bow type suggest either warship or merchant standard? Can't a specific bow be both?
 

Tam

Major
Registered Member
How does a bow type suggest either warship or merchant standard? Can't a specific bow be both?
Absolutely. Bow design tends more to reflect the sea conditions, e.g. North Atlantic vs. South Pacific, and whether the ship is intended more for open seas or littoral waters.

The shape of the bulbous bow and the shape of the bulb, where its locus is, top, center or bottom, whether its a delta, nabla or oval type, that's where you have more of a difference between a merchant vessel and a warship. But that reflects more of the purpose of the ship, rather than some kind of quality standard.
 

winton

New Member
Registered Member
Absolutely. Bow design tends more to reflect the sea conditions
So what is @Richard Santos talking about?

Lets go on the same vane. Wouldn't the fact that the US navy had several crashes lately suggest that the ships were built to a much lower standard than we had initially thought? Seems plausible given whats happen.

The 075 looks like its been built with all the lessons from other professional navies. Not so much the US
(or Norway for that matter) who have adopted different philosophies.
 

taxiya

Major
Registered Member
Straight raked bows are popular because they are cheap to make, not because they are higher standard.

The curved clipper bow is more desired than a straight raked bow, but also more expensive to build. It is better than straight raked bow to keep waves to reach the deck in rough sea state. It also greatly increase buoyancy when the bow dips into the water. Many older built Navy ships choose this type.

Straight raked bow becomes popular in the Navies because it is easy and cheap to build. Just weld flat straight plates together, you get a ship. While to make that curve of a clipper bow out of steel plate, one need the huge press machine. There was a documentary recently talking about that press machine and how the Type 055 ships' clipper bow is made out of it. That machine can make any curve the designer want because it is computer controlled.

Prior of 055, the 052xs are using straight raked bows just like US Tico and Arleigh Burke.

The only advantage of Straight raked bow over clipper bow is that it has a little bigger volume at the bow which is preferred by commercial ships like most of the new yacht.
 

Tam

Major
Registered Member
Straight raked bows are popular because they are cheap to make, not because they are higher standard.

The curved clipper bow is more desired than a straight raked bow, but also more expensive to build. It is better than straight raked bow to keep waves to reach the deck in rough sea state. It also greatly increase buoyancy when the bow dips into the water. Many older built Navy ships choose this type.

Straight raked bow becomes popular in the Navies because it is easy and cheap to build. Just weld flat straight plates together, you get a ship. While to make that curve of a clipper bow out of steel plate, one need the huge press machine. There was a documentary recently talking about that press machine and how the Type 055 ships' clipper bow is made out of it. That machine can make any curve the designer want because it is computer controlled.

Prior of 055, the 052xs are using straight raked bows just like US Tico and Arleigh Burke.

The only advantage of Straight raked bow over clipper bow is that it has a little bigger volume at the bow which is preferred by commercial ships like most of the new yacht.

The reason for modern bow design is 100% dealing with hydrodynamics, buoyancy, and stability, relating to what type of ship this is, and what's the most efficient for this type and purpose of ship. It has nothing to do with cost. There are bow designs more efficient for 'fuller' designs such as bulk freighters, tankers and ULCCs that would displace up to 400,000 tons, and there are bow designs suitable for warships that displace 4,000 tons. Building the bow section of the ship is far from one of the costliest contributors to the ship, and for a warship, its about its sensor, management and weapons systems.

Bow designs change and continually change because engineers are still perpetually searching for the perfect hydrodynamic bow design given a ship type or purpose as requirements for fuel economy and other things continue to tighten.

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Most raked and clipper bow designs are generally accompanied by a bulbous bow, so its never a simple geometry anyway regardless of how it looks above the water. For warships, the bulb would contain a hull sonar but for merchant vessels, the bulb is hydrodynamic reasons only. With warships, the bulb tends to be more rounded or full at the bottom, while on merchant vessels it tends to be more fuller and rounder at the top. This has nothing to do with cost, but because merchant vessels are considered more 'fuller' designs with a much higher weight displacement.
 
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Tam

Major
Registered Member
So what is @Richard Santos talking about?

Lets go on the same vane. Wouldn't the fact that the US navy had several crashes lately suggest that the ships were built to a much lower standard than we had initially thought? Seems plausible given whats happen.

The 075 looks like its been built with all the lessons from other professional navies. Not so much the US
(or Norway for that matter) who have adopted different philosophies.
US Navy having several crashes have more to do with questionable seamanship and bad luck. The fact that the Burkes survived despite being cleaved by modern freighters or tankers is a testimony to the ship's bulkhead design. Of course, you never mess around with a modern freighter or tanker that is at least twice and more of your displacement, the higher the ship's total displacement is, the stronger the keel is, and can you imagine how strong the keel is for a ship that can displace up to 400,000 tons. As for Norway, I think no one remembered to close the doors inside the ship and that ship flooded relatively quickly.
 

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