071 LPD thread

[Jeff Head]

re: PLAN Type 071 LPD & its Landing Craft

It occured to me there is another way to make a LPD hold 6 big LCACs. It is to use a lighter aboard ship (LASH) configuration instead of a standard wet well deck. This would allow 6 loaded LCACs to be stored in two layers in a 071 sized hull. I am not sure if it would be feasible to have a helicopter deck over the well without significantly increasing 071's freeboard.

Interesting.

The LASH system was designed for carrying "Lighters" which are basically barges, aboard transport vessels to move them over long distances by sea. Ultimately, because of the regualtions involved with the barges themselves and costs associated with those regulations once a lighter/barge was carried onto the inland waterways, the system became economically infeasable and has pretty much dried up.

Basically it involved having a lift that would pick up the barges (sometimes two at a time) and then stow them on deck.

​

To make such a system work on an LPD or LHD you would have to put a lift system at the back of the ship and then set up a two level well deck where you could place the upper LCACs on rails or sliders of some type so they could be pushed back at that level. You would probably also add another vehicle loading deck so you could load them on that level too, otherwise you would have to load them all once in the water by shullting them to the lower, "wet" portion of the well deck.

It probably could be done, but you would end up adding a lot of vertical weight to accomodate the 2nd level of LCACs, and then, because of the air assault capability of these ships, you would have to have the helo deck above all of that.

I just do not think it would be very feasible for the rapid loading and unloading of LCACs, but it could be done. Naval architects would have to put their heads together and figure it out. Perhaps they have already considered it and that is why we do not see the technology being applied. I just don't know.

 

[Engineer]

re: PLAN Type 071 LPD & its Landing Craft

Well, the PLAN Type 071 LPD is closest in size and function to the San Antonio Class LPD in the US Navy. The Wasp Class LHD is a much larger vessel.

However, when it comes to the LCAC and its fit, that doesn't matter because the well decks on both US vessels are exactly the same size.

The Type 726 PLAN LCAC is actually larger than the US LCAC. And that size makes a difference.

Here's the San Antonio well deck compared to the US LCAC;

San Antonio well deck width: 50 ft.
US LCAC width: 47 ft.

This gives the US well deck a full three feet clearance, 1 1/2 feet on each side.

By comparison, here's the PLAN Type 071 and the Type 726 LCAC:

Type 071 LPD well deck width: 53.5 ft.
Type 725 LCAC width: 52 ft

This means there is only 9 inches of clearance on each side for the Chinese LCAC...1 1/2 foot total clearance.

This makes it much harder to maneuver a Chinese LCAC into a Type 071 at sea...very hard indeed in any sea state beyond calm. Even then it would be hard.

Here's the overall LCAC and LPD dimensions:

US Navy LCAC:
Length: 87 ft
Width: 47 ft

Type 726 PLAN LCAC:
Length: 98 ft.
Width: 52 ft

Type 071 well Deck:
Length: 53-54 ft.
Width: 400 ft. (Approx)

San Antonio Well Deck:
Length: 267 ft.
Width: 50 ft.

I think size is least of the problems. When you look at US LCAC, you see there are two nozzles above the vessel for control of side-slip motion. Chinese LCAC lack those nozzles, so may well be under-actuated. That may be the reason why Chinese LCAC is still not in production despite being tested for years.

 

[Jeff Head]

re: PLAN Type 071 LPD & its Landing Craft

I think size is least of the problems. When you look at US LCAC, you see there are two nozzles above the vessel for control of side-slip motion. Chinese LCAC lack those nozzles, so may well be under-actuated. That may be the reason why Chinese LCAC is still not in production despite being tested for years.

That's an excellent point.

I had not noticed that.

But still, the Type 071 leaves very, very little room given the width of the Type 726 LCAC and the width of the Type 071 well deck. Even with better actuation, in any sea state past 0 or 1, it would be very, very difficult to put that vessel in that hole. Even in calm waters I will not be too easy.

 

[chuck731]

re: PLAN Type 071 LPD & its Landing Craft

When moving slowly, an air cushioned vehicle's inflated skirt and the air in it forms a sort of soft bumper. The elasticity of these inflated skirts gives at least another 2 feet of play for the vehicle on each side

 

[philbob]

re: PLAN Type 071 LPD & its Landing Craft

perhaps this why construction has seem to suspended? I remmeber back in 2007-2010 people were talking like there would be alot more built but that seems to have ended its maybe another example of experimentation that the PLAN is know for (to be honest this is their greatest trait IMO)

 

[asif iqbal]

re: PLAN Type 071 LPD & its Landing Craft

Type 071 LPD through the Red Sea Good navigation experience for the captain and crew

 

[asif iqbal]

re: PLAN Type 071 LPD & its Landing Craft

http://i4.photobucket.com/albums/y116/aziqbal/6322a91a6bf504d39dadabceabe50589_zps9e6855ef.jpg[/IMG

[IMG]http://i4.photobucket.com/albums/y116/aziqbal/431bfdc9d3779bc62af3150848029598_zpsb1320503.jpg

 

[Jeff Head]

re: PLAN Type 071 LPD & its Landing Craft

Type 071 LPD through the Red Sea Good navigation experience for the captain and crew

Are they heading north? Are they going to pass through the Suez canal into the Med?

 

[i.e.]

re: PLAN Type 071 LPD & its Landing Craft

I think size is least of the problems. When you look at US LCAC, you see there are two nozzles above the vessel for control of side-slip motion. Chinese LCAC lack those nozzles, so may well be under-actuated. That may be the reason why Chinese LCAC is still not in production despite being tested for years.

nose nozzles are the turbine exhaust pipes. not for steering. steering is done solely on the vanes on the ducted fans in the rear.

the issue with the tight fit of chinese LCAC is actually the narrow beam to length ratio of type 071, ...its/ something close to 1:8 which is closer to a frigate then to San Antonio class which is about 1:6.5, beam to length, infact San Antonio is about 4 meter wider than type 071.

the issue is that they wanted a higher displacement. but do it with about the same propulsion as a san antonio. probably the higher displacement is all eaten up by the structural strength needed for a narrower hull. dohh!

come to think of it... the chinese LCAC prob suffers from the narrow beam of the type 071 class too. as it is designed to just be able to fit into the bay of type 071. so it has to be rediculously narrow. but the turbines don't scale well with a narrower hull smaller displacement. so it ends up has less capacity vehicle.

I suspect the next generation of LPDs PLA commission would not be on the current 071 hull. it would be something wider.

====

completely different but related thought:

Huntington Ingalls Industries is markting a BMD variant of the San Antonio Class... basically a

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which I think is an poor way to go for San Antonio's class precisely because its wider hull, as it is slow and can't keep up with the fleet. but, an excellent way for PLAN for its 071 hulls precisely because its narrow hull...

change all its diesels with Gas turbines. may be the GT-25000 and its derivatives. mount a current type 052D radars on the ship and pack it full of VLSs. and we have a 26-8 kt, 25000 ton ship that is basically a cheap but powerful cruiser. it can even keep its helopads and hangar for ASW duties!
forget the 055 class cruiser/destroyer... this will put the most ship and fire power in the water in the shortest amount of time since the 051 programs.

 

[Kurt]

re: PLAN Type 071 LPD & its Landing Craft

Interesting.

The LASH system was designed for carrying "Lighters" which are basically barges, aboard transport vessels to move them over long distances by sea. Ultimately, because of the regualtions involved with the barges themselves and costs associated with those regulations once a lighter/barge was carried onto the inland waterways, the system became economically infeasable and has pretty much dried up.

Basically it involved having a lift that would pick up the barges (sometimes two at a time) and then stow them on deck.

​

To make such a system work on an LPD or LHD you would have to put a lift system at the back of the ship and then set up a two level well deck where you could place the upper LCACs on rails or sliders of some type so they could be pushed back at that level. You would probably also add another vehicle loading deck so you could load them on that level too, otherwise you would have to load them all once in the water by shullting them to the lower, "wet" portion of the well deck.

It probably could be done, but you would end up adding a lot of vertical weight to accomodate the 2nd level of LCACs, and then, because of the air assault capability of these ships, you would have to have the helo deck above all of that.

I just do not think it would be very feasible for the rapid loading and unloading of LCACs, but it could be done. Naval architects would have to put their heads together and figure it out. Perhaps they have already considered it and that is why we do not see the technology being applied. I just don't know.

Something like that was done with the Australian Kanimbla class.

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The problem becomes visible if you imagine operation in higher sea states with the ship moving and the craft on the crane as a pendulum moving as well.