Center for International Maritime Security:
CIMSEC sat down with Captain Mark Vandroff to solicit his expert insight into the complex world of acquisition and the future of the U.S. Navy’s destroyers. CAPT Vandroff is the Program Manager of the U.S. Navy’s DDG-51 program, the Arleigh Burke-class destroyer, which is the most numerous warship in the U.S. Navy. In the first part of this two part interview series, CAPT Vandroff discusses the capability offered by the SPY-6 Air and Missile Defense Radar, the differences in warship design between the currently serving Flight IIA and upcoming Flight III variants, and the U.S. Navy’s ongoing Future Surface Combatant Study.
This is a big year for your program. It is the fiscal year where you begin procuring the new Flight III destroyers. Can you talk about the differences from the Flight IIA to the Flight III?
The raison d’etre of Flight III is fielding AMDR. SPY 6 is the designation for that radar as it goes on a DDG-51. That radar program may yield other radar technologies because it is very exciting technology. The Flight III gets the AMDR SPY-6 radar onto a DDG-51 platform, replacing the SPY-1 radar currently in use. That radar is a significant, multi-generational leap forward in radar technology. In the same space and roughly twice as much power, it produces over 35 times as much power out. Between the power efficiency and sensitivity of the radar, it is a huge step forward. It also includes other very desirable radar features such as a much improved resistance to advanced counter-radar jamming techniques and the ability to integrate seamlessly through a radar system controller, not only the S-Band SPY-6, but also an additional separate frequency input. It can use the multi-frequency input for better targeting, and a lot of good things happen for targeting and your reaction time by synthesizing multi-band input. We hook up the SPY-6 AMDR, which is a S-BAND radar, with the existing and already planned for DDG-51 X-Band emitter AN/SPQ-9B to get the full radar suite for the Flight III.
If it were all that simple I would tell you to talk to my colleague, CAPT Seiko Okano, she’s the SPY-6 program manager. I would not have to do very much and she would just deliver me a different radar. But the radar requires us to do things to the ship to be able to accommodate it.
The radar takes about twice as much power. We had to take the ship from three, 3 megawatt (MW) generators to three, 4 MW generators because we never have three on at one time for purposes of redundancy. We always calculate what would happen if you had to run on two of the three. When we calculate what our battle loads are and can we handle them, we always calculate to whether we can handle them with two of the three generators if one of them is down for whatever reason. That’s how you design a redundant warship.
So when we up the power out of our generators to four megawatts we run into our first physics challenge. When we up the power we have to do one of two things, either increase the voltage or increase the current. At a certain level of current, it becomes difficult and at times unsafe to run a certain amount of current through the kind of wiring we would put on a ship. With what we currently have, if we had to up the power anymore we would be hitting those limits. So we have to up the voltage, which is easily done. We’ve got 4160 volt power on aircraft carriers, on DDG-1000, so we had to implement that for Flight III. There’s a separate 4160 bus for powering the radar, and then we stepped down with transformers for our 450 loads that exist. That allows us to power the radar, and at the same time power the rest of the ship the way it is powered in a Flight IIA. That was the first change and we’ve done a lot of work to make sure that electric plant design will be safe, stable, redundant, and survivable in battle. That’s been the work of the last two or three years, and a lot of work is put into splitting those loads out.We have a 4160 distribution system with the existing 450 distribution system that we could do that with. That was the first ship side technical challenge that I would say now we’re pretty much through. The new generators, the four MW generators, have gone through their critical design review and they’re just now starting production.
The next thing we needed to look at was actually powering the radar. The radar runs off 4160 converted 1000 volt DC to AC. The equipment to convert that and condition it was similar to what DDG-1000 uses, they use that power conversion module on their SPY-3 radar. We competed, it was a full and open competition, we got many bids, and DRS (Diagnostic/Retrieval Systems, Inc) won the work. They came to us with a box that was based on their DDG-1000 design, but had a couple of generations of power monitoring and power conditioning improvement on top of that incorporating lessons learned from the commercial world. That’s been through its preliminary and critical design review and its gone into production now. That gets us power to the radar, and power to the electric grid.
If you think about power what else does the radar need? The radar needs more cooling. A more powerful radar produces more heat. For reference, a refrigerating ton is the amount of cooling I would have if I rolled a ton of ice into this room and let it melt for 24 hours. A DDG-51 today has about 1000 tons of cooling. Once you install the SPY-6 you really need 1400-1500 tons of cooling. When we were starting the early preliminary design, NAVSEA already had an energy saving initiative. It was a plan to take the Navy standard 200 ton plants and equip them with a more fuel efficient compressor, and some other design improvements. All of that’s made by York Navy Systems in Pennsylvania that makes that standard 200 ton plant. NAVSEA works with them, and they are actually in the process now, and there’s a working prototype of the improved 200 ton plant that is putting out over 325 tons of cooling and it is just going through its equipment qualification to make sure the new machine will pass all the Navy standards for shock survivability. We are getting ready to put the initial orders for those to deliver to the Flight III because when you put five of those you get an excess of 1500, and that will give us more than enough cooling to accommodate the new cooling loads. So those have been the key components in changing the ship for the Flight III.
In terms of weight, if you put everything that a SPY-6 uses and everything a SPY-1 uses on a scale they roughly balance. However, SPY-1 forms the signal in a signal generator and then transfers that up to the array, so that signal generator is lower in the ship. Because SPY-6 is an active array, the signal is generated on-array, so that means the arrays are heavier. Arrays go up high so that means the weight goes up high. If you are on a ship you are not crazy about high weight. You want to be like a running back, you want your weight low so it is hard to knock you over. The last thing we did is move some weight around in the ship. We thickened up the hull and the scantlings, which are the ribs of the hull. That offsets the high weight by putting extra weight low, and moves your center of gravity back down. The center of gravity of a Flight III will be roughly where the Flight IIA’s center of gravity is now. We are still concerned about things like performance for flight ops and maneuvering, and what that means for the pitch and roll in different sea states. We have the advantage of Naval Surface Warfare Center Caderock’s great new MASK tank where they can do all sorts of different sea states all in one tank. We have the scale model of the Flight III being built out at Carderock and that will go through all its tank testing with an idea to make sure that as we are designing the ship we know where we are for maneuvering the ship.
Those are the big shipboard changes that facilitate the introduction of the radar. It is cool for me as the ship guy to talk about moving weight around to get good center of gravity, or getting the new electrical plant, but all that has to mean something to the warfighter. What the warfighter gets out of the Flight III is that improved radar performance from the new SPY-6 radar tied into the existing AN/SPQ-9 radar and those synthesized together for better performance in the atmospheric regime and the ballistic missile defense regime. It offers tremendous improvement in capability in both of those regimes.
Because AMDR is such a tremendous increase in capability, how does this affect the DDG-51’s growth margins?
That is one of the reasons we looked at things like the extra cooling and the extra power. If you look at where the Flight IIA is, the Flight IIA has about one and a half MW of service life power growth, and about 200 tons of cooling growth. If you added up every load on a Flight IIA today you would get something just over 4 MW of load, and if you put two 3 megawatt generators on the load together to power those four megawatts. You pay an efficiency penalty when you parallel two generators together, so two 3 megawatt generators gives about 5.8 MW of usable power and about 200 KW of the generators fighting themselves at peak. That is about one and a half MW to one and two thirds MW of margin on a IIA today. The Flight III will have a heavier load. A full battle load will be up over 5.5 MW, but we will be well over 7.5 MW when we put two four MW machines online together. We will have another two MW of power. The total cooling reserve will be about 200 refrigeration tons to 300 refrigeration tons.
