Could the US Navy's Next Cruiser be Derived From the San Antonio Class LPD?

Huntington Ingalls Industries is in discussions with defense officials about potentially putting missile defense radars and laser weapons on San Antonio-class amphibious transport docks, a company executive said Jan. 13.

“You can put a lot of additional weight on the ship and you can put … some modern technologies like ballistic missile defense radars that are very heavy,” Brian Cuccias, corporate vice president at HII and president of Ingalls Shipbuilding, told reporters on the sidelines of a Surface Navy Association symposium in Arlington, Virginia. “We think it’s a great idea.”

The vessels, which are manufactured by the company, have design features that make them well-suited to carry a large radar, he said

“You have a design life margin …. on some ships that say you can only take so much more weight before you have a stability issue or, you know, you don’t have your margins,” he said. “When you close in the well deck of the LPD ship you expand that capability to take a lot of weight, and the stability on LPD is such you can actually put weight up high” where missile defense radars would be positioned.

One of the challenges of hosting ballistic missile defense radars is the need to power them and cool them, Cuccias noted. “You need arrangeable volume for power generation. You need arrangeable volume to have cooling,” he said. “LPD allows for that. … The basic bones of the ship allow that to take place.”

[...]

The Navy is hoping to equip some of its ships with high-powered lasers and electromagnetic railguns to enable them to shoot down enemy missiles and aircraft and attack surface targets with the emerging technologies. Cuccias said the LPD could potentially host those types of weapons.

link.

The article above does not say the ships would be the replacements for the Tico cruisers, but that is effectively what is being talked about.  So let's consider it.

On the Plus side:

1.  The  LPD's are huge.  Just look at the picture right above.  There are two San Antonios present side by side and a Ticonderoga in the foreground.  You can see the vast size difference.  The LPD's displace 28,000 tons, whereas the Ticos displace ~9,800 tons.

2.  The volume is huge within the San Antonios as well.  There's plenty of space to place pretty much anything.

3.  The hull is a known quantity and would save some money by being reused.  A simplified form of the hull is being used for the LX(R).

On the Down Side:

1.  The LPDs need a complete revamp for their propulsion.  Right now they use diesel engines able to move the hull a sedate 22 knots.  The Ticos move at a rate of ~32, almost 33 knots and this is far slower than the carriers with their nuclear propulsion.  

2.  The hull needs to be updated for carrying more helicopters - we got away from strictly specialist ships after the ending of the Burke Flight I destroyers.  The flight deck is plenty large, but the hangar space is far, far too small.  

3.  The hull needs to rebuilt so far, far more VLS cells can be added to the ship.  Currently, there are provisions for 8 VLS cells.  A cruiser needs 120+ and probably ought to use the more up to date Mark 57 vs the Mk 41 allowing for dispersing the cells through the hull for better survivability and  larger missiles.

4.  The lasers and railguns speculated on are a great idea...but its unknown how much they will cost in the end.  The savings of using the LPD hull may be a very, very small portion of the cost.  

5.  Power generation.  The diesel engines on the LPD-17 class are not going to be sufficient for the continual firing of railguns or fleet defense lasers.  This is only worsened by the fact in combat the ships must move as well.  However, there is the volume to replace, well everything and significantly add on.

6.  Its highly likely the electric propulsion system for the Zumwalt class will have to be adapted for the new LPD derived cruiser.  This would mean needing to upscale the system: the Zumwalts are 19,000 tons.  The new LPD derived cruisers would be at least 28,000 tons.  And scaling is a huge issue with any project.

Idle Thoughts:

1.  I suppose if the American definition of 'destroyer' is 19,000 tons now with the Zumwalts, it would make 'sense' the cruisers would be 28,000 tons.  :)

2.  This has potential, but I worry this will get killed the same way the Zumwalts did through rising costs triggering the death spiral.

3.   I also wonder about the survivability of the ship that was originally an amphib.  They are built with different expectations than the cruisers and destroyers.

4.  A dedicated BMD ship is a bad idea (see image right above and below).  The use of lasers and railguns will really change that design as well.

its an interesting idea.  We'll see if it goes anywhere.