071 LPD thread

[Blitzo]

I have had a little think about this and as stated before it would be highly unlikely that a LCU could manage anywhere close to 55-60 knots like a LCAC with a flat bottom hull this would not work

This now further diminishes the need for such a craft so now I do another conclusion

LCU slow to deploy and slow speed
LCAC fast to deploy and fast to run

So that's 2 points for LCAC and 0 points to LCU ( before I was giving LCU 1 point)

If they manage to significantly increase the speed then still I would give it only 0.5 points because it could never be as fast as LCAC which is still less than LCAC which gets 2 full marks

If you are talking about larger LCU then it's a non starter since China has around 30 x LST and 100s of other small utility craft

In in conclusion the scope for LCU in PLAN is very very small

I think LCACs with full loads can only do 40 knots. Even the new ship to shore connector/LCAC replacement is meant to do 35 knots with a full load

That said, I do not think even a high speed LCU can match LCAC speeds with a full load either. (however, I did say the PLAN should look into unique hull forms -- such as the BMT tri hull LCU design that shen posted which could do near LCAC speeds)

But there are other aforementioned advantages that LCUs have, even if they only have something like 3/4 of LCAC speed:
-cheaper, more conventional/less advanced than LCACs
-more can be built concurrently by smaller shipyards (because they are less advanced than LCACs)
-more (potentially twice as many) can be stored in an LPD's well deck, meaning if there are any missions that require storming a beach where the number of AFVs is more important, then LCUs are preferred
-they are more likely replacements for all the smaller conventional legacy LCUs in the PLAN's inventory, which obviously will not be replaced by LCACs

LCACs, have advantages such as:
-able to traverse harder to reach assault zones (but potentially not very useful in a TW scenario where ROC military will likely have surveillance capability of most of their coastal regions)
-likely a little bit faster than a high speed LCU (but by how much? twice as fast? One and a half times faster? one quarter faster?)
-faster to deploy from well deck


it's all a matter of degrees, and each of the advantages both types have will fade and grow stronger depending on the mission.

But at the end of the day this isn't a question of "LCAC vs high speed LCU, which is better?"
It is a question of what PLAN's needs are, and what their shipbuilding industry can produce.

The absolute, raw performance of an LCAC and an LCU are a factor to consider, but cost, construction/induction rate, availability, are also very important factors to consider and I'd say all those areas tilt heavily in favour of a high speed LCU compared to an LCAC, at least until smaller shipyards master LCAC technology (whenever that may be, if ever).

Look at it this way: a high speed LCU and LCAC combination will be high low combo like J-10 and J-11B/flanker, or F-16 and F-15, or F-35 and F-22.
One product is a slightly lower capability but with lower cost, greater availability and numbers, lower maintenance platform, whereas the other is a higher capability, higher performance, but higher cost, lower availability and numbers, higher maintenance platform. The two could potentially be able to complement each other.

I'm not going to say this is something PLAN absolutely needs, but I think it is worth looking into. I don't think either of us are able to say whether a high speed LCU has big or small "scope" for the PLAN.

 

[Blitzo]

On the subject of cost, a total of 8 LCU Mk 10 purchased for 35 million pounds between 2001 and 2003, which comes to about 6 million pounds per unit of 2013 pounds when considering inflation, and about 10 million USD today.


Whereas a single LCAC purchased in fiscal year 1990 was 24.4 million USD per unit, so about 44.4 million USD per unit today accounting for inflation.

And remember, UK military products tend to be more expensive than US products of similar capability, so the ratio for actual unit production (not to mention maintenance cost) of LCU versus LCAC would likely be even more skewed in LCU's favour even for a high speed LCU. Let's pretend a high speed LCU is twice as expensive as conventional LCU, which is obviously a crazy suggestion -- you still are able to buy twice the number of high speed LCUs versus LCACs!

Even the USN's next generation SSC LCAC replacement is pegged at a massive 56 million USD per unit!

When we consider how immature PLAN's LCAC design and subsystem industry is, it isn't unrealistic at all to say the cost ratio between a PLAN built high speed LCU and 726 LCAC would be quite heavily skewed in the LCU's favour given the only major challenges in designing a high speed LCU will be the hull form. Propulsion, navigation, ship control, etc, can all use existing or adaptations of similar subsystems whereas in LCAC everything has to be developed from the ground up -- its uniqueness in concept is its tripwire in cost.


again I'm not saying PLAN should abandon LCAC for LCU, but I'm saying they should look into high speed LCUs as a complement given how expensive LCAC is and how few can likely be procured. Frankly it is a very open ended statement, and I don't think anyone can reasonably disagree with it confidently knowing that such a suggestion is preposterous.

 

[Jeff Head]

The Chinese do have a functional LCU. It is the Type 074A. It is somewhat larger than the US LCU 1600, and will not fit into the well deck of the Type 071. Its bridge and mast are too tall.

I am surprised that they have not developed a version of this vessel that could be used for the Type 071. They seem like very decent LCUs.

Here are some pics:

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And here's a higher res picture of two of them togther.

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I am not sure how many of these have been built. About 550-600 tons. 13 or 14 cew. Very similar to the US LCU. When you compare them, you can see how the US LCU was designed to fit into the well deck. Notice the bridge and mast of the two:

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Given the obvious problems the PLAN has had with bringing forward any numbes of LCACs, a good LCU, where they could fit two into the well deck (each one can carry three tanks), would make a lot of sense to me...albeit, they would also make for a slower assault to shore.

Great discussion guys.

 

[Jeff Head]

For a modified Type 074A (I will call it Type 074B), here's an idea.

- Lower bridge.
- Lower mast.
- Clear equipment/personnel area fore to aft.
- Rear Ramp for loading.

​

Clearly simply a modified Type 074A so that it can fit into the Type 071 well-deck.

 

[wtlh]

Is a bridge this low safe for navigation for a vessel of this size?

 

[Jeff Head]

Is a bridge this low safe for navigation for a vessel of this size?

Yes. The US LCU 1600, which is shown below, has an even lower bridge, but has a range of 1,200 nautical miles.

 

[Blitzo]

For a modified Type 074A (I will call it Tyep 074B), here's an idea.

- Lower bridge.
- Lower mast.
- Clear equipment/personnel area fore to aft.
- Rear Ramp for loading.

Clearly simply a modified Type 074A so that it can fit into the Type 071 well-deck.

Would be interesting, however, a few issues that may arise is that it probably won't be very fast, and will be harder to develop into a higher speed LCU than a smaller LCU, and also, larger LCUs could be more vulnerable because you are putting more AFVs into one craft.
Dispersing AFVs among more smaller high speed LCUs means the opposing force will have more individual targets.

That said, I can see the attractiveness for both.

 

[Jeff Head]

Would be interesting, however, a few issues that may arise is that it probably won't be very fast, and will be harder to develop into a higher speed LCU than a smaller LCU, and also, larger LCUs could be more vulnerable because you are putting more AFVs into one craft.
Dispersing AFVs among more smaller high speed LCUs means the opposing force will have more individual targets.

That said, I can see the attractiveness for both.

Well, it was not my intent to propose this Type 74B as a high speed LCU.

More of a replication of the US Navy's path.

right now, the PLAN is having a difficult time getting their LCACs on track. I suspect there are design, engineering/propulsion problems.

So, they could increase their flexibility and add a viable, good landing craft by developing an LCU that will fit into the Type 071 well deck.

 

[shen]

Here is a new Russian landing craft with 35 knots speed.

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It has an innovative air bubble injection system to reduce hull resistance. But look at how much raw horsepower is still needed to get in up to speed.

 

[Blitzo]

Here is a new Russian landing craft with 35 knots speed.

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It has an innovative air bubble injection system to reduce hull resistance. But look at how much raw horsepower is still needed to get in up to speed.

Worth noting this craft is about twice the weight of the mk 10 sized LCU I was considering