Common Hull Strategy: Surface Combatants

As shipbuilding costs have continued to rise, several suggestions have been made to help bring down the costs in shipbuilding. Among the many suggestions, one that continues to rise to the top is for the Navy to use common hull strategies for ships, similar to how the Spruance class destroyer hull and Ticonderoga class cruiser used the same hull. Another aspect of the common hull strategy is the type vs model debate, for example the DDG-51 represents a single type of ship with three models. These types of model changes for a ship type are built from lessons learned in production and adapted to meet requirements in an evolutionary model as technology changes, so they aren't necessarily a bad thing.

Defense Daily has an article out today describing some of the efforts of NAVSEA to evaluate reducing the number of hull types the Navy operates. Today, the Navy operates 21 types of ships and there are 29 models based on those 21 types. The process as described in the Defense Daily article focuses on amphibious ships and surface combatants (available here, #16). This post is specific to Surface Combatants.

Surface Combatants

On the surface combatant side, the most attractive from an affordability standpoint is to reuse DDG-1000 for the next generation cruiser and select one of the two Littoral Combat Ship designs and build on that to be the DDG-51 replacement, Goddard explained.

"In the end, you end up with just three types, and one could argue this is just two types of ships, a LCS-type, a small combatant and a large combatant with the cruiser just being another model of the destroyer," he said.

Even if the Navy doesn't build another surface combatant in the next decade, between 2012 - 2022 the US Navy will reach the zenith of strike power from the sea with its surface combatant fleet. Even without the proposed DDG-1000s. The Navy will have 22 modernized Cruisers each equipped with 136 VLS cells, 16 of which are occupied by 64 ESSMs, sporting a total of 184 vertically launched missiles each Cruiser. Three of the 22 Cruisers will also have a mature, modernized, independently deployable ballistic missile intercept capability. Combined the 22 modernized Cruisers will carry 4048 independently launched guided missiles in their vertical launchers.

The Navy will also have a force of 62 Destroyers, with 28 of those destroyers equipped with 92 VLS cells, and the remaining 34 destroyers equipped with 96 VLS cells. 22 of the 34 destroyers with 96 VLS cells occupy four of those VLS cells with quad packed ESSM, giving those 22 destroyers a total of 108 vertically launched missiles each. Combined the 62 Destroyers can carry 6104 independently launched guided missiles in their vertical launchers.

Those 84 ships have a combined 10,152 VLS launched missiles including ESSM in quadpacks in the Tactical VLS cells, and I'm not counting Harpoons.

In that context, lets review what Goddard is saying. The DDG-1000 and the CG(X) programs would be combined to form a single class of ship. Based on current numbers, there are 7 proposed DDG-1000s and 19 proposed CG(X), not including the nuclear requirement, which would total 26 of these advanced 14,000 ton cruisers. The DDG-1000 design includes 80 Advanced VLS launchers, which we will estimate is around 208 total guided missiles per ship. Combined that means 7 DDG-1000s and 19 CG(X) would have around 5408 guided missiles in their vertical launchers.

Under a LCS common hull strategy, to retain the strike power of the upcoming 2012-2020 AEGIS fleet, 4744 missiles are required on the LCS hull. The General Dynamics Multi-mission combatant claims 32 VLS cells, but DID claims 16 Tactical Length VLS cells. To split the difference, we'll use the number 32 total missiles per ship. In order to make up the difference between the 26 DDG-1000/CG(X) ships and the AEGIS fleet of today using the General Dynamics MMC version of the LCS, the US Navy would need to build 148 LCS combatants.

The Lockheed Martin Multi-mission combatant is claimed to have 16 Strike Length VLS cells, but the Israeli version also appears to have VLS for 16 Barak missiles. While the RIM-162 ESSM is bigger than the Barak missile, I'm assuming the LM version could support 16 ESSM which allows us to estimate 32 missiles as well, but half are ESSM. In order to make up the difference with the Lockheed Martin MMC version of the LCS, the US Navy would need to build 148 LCS hull ships to equal missile totals, but 297 LM LCS to equal the same number of MK41 VLS cells.

It would appear that the CG-52/DDG-51 fleet is the most brilliant strike fleet ever built. It would also appear any future fleet that considers the DDG-1000 / LCS MMC mix of designs to replace the CG-52/DDG-51 fleet is going to require an enormous investment. I estimated around $180 billion dollars using the 26 / 148 mix.

An alternative would be to build 19 CG(X) and 19 DDG-1000, basically 1 of each escort for the 10 CSGs and 9 ESGs, and 71 GD LCS MMCs. That option would allow the Navy to sustain the number of VLS cells in the future fleet. At an average of $3.3 billion per DDG-1000 / CG(X) and an average of $800 million for the LCS (same numbers used in all estimations), that 38 / 71 mix would cost around $182 billion dollars, roughly the same as the 26 /148 mix.

That is why when Bob Work went to testify before Congress last year, he recommended a major modernization and life extension program for the existing AEGIS ships and a new design effort for the future fleet (full report here PDF). Rear Adm. Charles Goddard is wasting his time looking for common hulls among the 2 DDG-1000 and 2 LCS hulls provided, because he is not going to find the magic formula that reduces shipbuilding costs and sustains the fleet anywhere near current levels without new designs.