The Navy and two shipbuilders are moving forward with the Flight III upgrade to the Arleigh Burke guided missile destroyers (DDG-51), which adds an air and missile defense radar to the ship class starting this fiscal year.
General Dynamics Bath Iron Works and Ingalls Shipbuilding are collaborating on detail design of the Flight III upgrade, which should be complete by the summer of 2017, and both have responded to the Navy’s draft request for proposals (RFP) for Fiscal Year 2016 ship construction, DDG-51 program manager Capt. Mark Vandroff told USNI News in a Nov. 12 interview.
The two yards have taken the Navy’s preliminary design for Flight III, which was broken into 17 individual statements of work, and are working together to develop a 3D model of the ship that includes all equipment and distributed systems.
“We always planned to complete that some time in the late summer of 2017 because a ship that’s appropriated in FY ’16 generally spends about a year [procuring materials],” Vandroff said.
“A typical FY ‘16 ship wouldn’t start until the later part of 2017, and we would want the detail design to be done about the same time.”
The air and missile defense radar, Raytheon’s AN/SPY-6, is in the engineering and manufacturing development phase but is on track to be ready in time for ship construction, Vandroff said. The radar development is run out of the Program Executive Office for Integrated Warfare Systems, which has passed information to the shipyards through Vandroff’s office to support the Flight III detail design.
Virtually all the changes in Flight III support the addition of the SPY-6 radar. Vandroff said the primary requirements for the flight upgrade were to add additional power, cooling and weight margins for the ship’s service life.
“I could put a SPY-6 onto a DDG Flight IIA today with the power plant it has today, and it would work fine,” he said.
“There would be enough power. But there would be no growth margin for a 40-year service life. And if we’re building a new ship, we want to have similar growth margins on the Flight III that we’ve had historically on DDG-51s.”
To achieve sufficient power margins, Vandroff said the program office chose to replace the three Rolls Royce 3-megawatt generators on the Flight IIA ships with Rolls Royce’s 4-megawatt generator used on the Zumwalt-class destroyers (DDG-1000), which take up the same footprint on the ship and therefore give more power without forcing any ship design changes.
The new generators, however, make power at 4,160 volts instead of 450 volts – which Vandroff said is more efficient and safer, but necessitates more expensive switch gears. The America-class amphibious assault ship (LHA-6) uses the 4,160-volt power plant as well, so the DDG-51 program took the big deck’s electrical distribution system to support the new larger generators.
The SPY-6 radar is much bigger than the old SPY-1D(V), which means it makes more heat and requires more cooling capacity. The Flight IIA ships could handle the bigger radar, Vandroff said, but would again leave no margin. The Flight IIA ships use five air conditioning plants that produce 200 tons of cooling each – but the San Antonio-class amphibious transport dock (LPD-17) program was already in the middle of an effort to improve those AC units. By developing advances in the magnetic bearings, motor control of the compressor and more, the LPD program and Naval Sea System Command’s (NAVSEA) engineering directorate were able to get the AC plants to put out 300 tons of cooling each, rather than 200.
Vandroff said the improved plants cost a bit more, but “for us it came along at the right time so we could provide the additional cooling we needed without increasing foot space.”
“Frankly, if we didn’t have the radar, I would still be doing this just because, I would be doing it as a savings of lifecycle money because these AC plants produce cooling more efficiently than the current ones,” he said.
“They’re slightly more expensive, but over a 40-year service life of the ship, what you pay to get a more expensive AC plant you more than make up for in fuel savings over the life of the ship.”
The new SPY-6 radar is not any heavier than the old SPY-1D(V), but the weight is distributed on the ship differently. The old radar has a separate signal generator, which is a heavy piece of equipment and is located lower in the ship for its own protection and for shipkeeping purposes. The SPY-6 is an active array radar, which means the signal is generated on the array itself – meaning the array is heavier but must still be placed at the top of the ship, throwing off the ship’s overall balance.
To bring the ship’s center of gravity back down, Vandroff said he wanted to make the hull thicker in some places and to thicken the scantlings, which has the added advantage of creating a more survivable hull in the event of an underwater explosion. A ship can only be so heavy and still be safe to steam, and Vandroff said that adding steel to the hull and scantlings stayed within the weight margins but left little room for growth in the future.
“To get back that growth margin, we changed the hull form a little bit in the stern, and I mean a little bit,” he said.
“So the stern is slightly wider and slightly less flared. That gives you a little more volume that the ship will displace, and that volume change gives you another few hundred tons of service life in the weight.”
By adding weight to the bottom of the ship and then adding back in some margin for growth, Vandroff said the Flight III configuration has a center of gravity “roughly where it was on a IIA.”
Overall, Vandroff said of the Flight III configuration, “the radar is new, the radar is a new thing, but everything else I described to you is not new – it’s the 1000’s generators, it’s the LPD-17’s AC plants, it’s LHA-6’s electrical distribution system. It’s all things we’ve used before, we just said, I’m going to go use what I’ve got on hand. And then steel and the shape of the ship.”
Aside from those must-haves to support the new radar, Vandroff said he’s working with the shipbuilders to add in a couple nice-to-haves as well.
First, he said, “if you’re going to have a ship with this much BMD (ballistic missile defense) capability, it would be really good perhaps to put your BMD commander on this ship as opposed to the carrier or somewhere else in the battle group. So do I need a few extra racks for a BMD commander and his flyaway team? So we’re moving around to get a little extra berthing. Would it be helpful if they had two or three extra consoles in [combat information center] in order to plan BMD missions from? Yes, that would be helpful. It doesn’t really change the ship, so we’ve redesigned the consoles.”
And second, the Navy learned when it upgraded USS John Paul Jones (DDG-53) that tearing out the Aegis Combat System to upgrade the hardware was a more challenging task than it ought to be.
“It should be easier to swap out equipment than it was with John Paul Jones. For John Paul Jones, we buried the vital combat system equipment on purpose in the Arleigh Burke design deep inside the hull, inside lots of steel and lots of structure because that makes it more survivable in damage condition,” he said.
“It also makes it harder to get out. 30 years ago when we first designed Aegis, there wasn’t the concept that, wow, information technology is going to change really fast and we’re going to want to swap out hardware on a more regular basis. You built a ship for a 30-year life. So we’re looking at … rapid removal routes. Things where we’re going to place combat system equipment so it’s still protected, but every one of them will have kind of an easy way off the ship, either by unbolting plates or by making sure there’s areas where distributed systems are not run so its’ an easier hull cut, so we can get things on and off the ship in the combat system faster.”
For all the changes going into the Flight III design, Vandroff said the Navy will get a ship with “tremendous capability” in the SPY-6 that is not only a “huge leap forward” in integrated air and missile defense but also is much better prepared to ward off jamming attacks; has the margins to support future weapons; and still feels the same to the average sailor walking through the ship.
Excluding the lead Flight III ship, Vandroff said the new ships won’t cost much more than the older ones. The average Flight IIA destroyer during the last three years of two-a-year construction across two shipyards cost $1.5 billion per destroyer. Vandroff said his office was in the midst of updating its cost estimate, but NAVSEA has estimated that the Flight III follow-on ships, under the same type of two-a-year multiyear buy, would cost $1.75 billion each and could drop in price as the radars become cheaper to build.
Vandroff could not, however, discuss the timing of the new Flight III ships. The draft RFP is out and the Navy has already responded to comments from industry, but Vandroff said he could not discuss any future actions in the competitive bidding process, including a release date for the final RFP.
