Navy Swaps Out Anti-Swarm Boat Guns on DDG-1000s<header class="entry-header" style="margin: 0px; padding: 0px; border-width: 0px 0px medium; border-bottom-style: none; face-size: 13px; vertical-align: baseline; face-family: Arial, Helvetica, sans-serif; line-height: 13px; color: rgb(68, 68, 68);">
By: Sam LaGrone
Published: August 5, 2014 4:04 PM
Updated: <time class="entry-date" style="margin: 0px; padding: 0px; border: 0px; face-size: inherit; vertical-align: baseline; face-family: inherit; face-style: inherit; face-variant: inherit; line-height: inherit; color: rgb(143, 119, 62);">August 5, 2014 4:25 PM</time></header>
he MK46 Mod 1 weapon system fires a round during a live-fire qualification exercise aboard the amphibious transport dock ship USS New Orleans (LPD-18). US NAvy Photo
The Navy has replaced two 57mm guns planned on the Zumwalt-class guided missile destroyer designed to fight off swarm boat attacks with a smaller pair of 30mm guns, Naval Sea Systems Command (NAVSEA) told USNI News on Monday.
The trio of Zumwalt-class ships were originally designed to field the BAE Systems MK 110 close-in gun system (CIGS) — a gun used on both classes of Littoral Combat Ships (LCS) — to provide the ship’s company options to fight off so-called swarm boat attacks of the ship as part of a 2005 critical design review (CDR).
“The basis of that decision was the expected performance of the gun and its munitions, coupled with desire for commonality in [Navy] and [the Coast Guard], according to a NAVSEA statement provided to USNI News.
But in order to save weight and costs, NAVSEA elected to install twin General Dynamics 30 mm Mk 46 Gun System instead.
NAVSEA said it continued to evaluate the Mk 110 after the 2005 CDR.
“Through 2010, various analysis efforts were conducted to assess the performance of potential cost-saving alternatives to the Mk 110 CIGS, for both procurement and life-cycle costs,” read the statement.
“The results of the analysis for alternative systems to the Mk 110 CIGS were not conclusive enough to recommend a shift in plan.”
The 57mm Mk 110 fires a 220 rounds/min at range of about nine nautical miles, according to information from BAE.
Following a 2012 review the Navy, “concluded that the MK46 was more effective than the MK110 CIGS,” according to NAVSEA.
“In addition to the increased capability, the change from MK110 to Mk 46 resulted in reduction in weight and significant cost avoidance, while still meeting requirements… that will provide a robust rapid fire capability and increased lethality against hostile surface targets approaching the ship.”
The 30mm Mk 46 has range 2.17 nautical miles and fires at a rate of 200 rounds/minute, according to the Navy.
NAVSEA did not elaborate on what the original requirements were the DDG-1000.
Zumwalt-class guided-missile destroyer DDG 1000 is floated out of dry dock at the General Dynamics Bath Iron Works shipyard on Oct. 28, 2013. US Navy Photo
Representatives of BAE Systems — the company that also manufactures the Zumwalt’s 155mm Advanced Gun System (AGS) — referred questions to the Navy.
The Mk 110 was to be integrated into the Raytheon designed combat systems of the minimally manned Zumwalt. It’s unclear how the Mk 46 — currently in use on the San Antonio-class (LPD-17) amphibious warship — will be integrated into the Zumwalts.
Messages left with Raytheon officials were not immediately returned.
Following the 2000 terrorist attack of USS Cole (DDG-67) and the rise in Iranian small attack boats, the Navy became acutely concerned with so-called swarms of small and fast surface craft that could overwhelm the existing defenses of a warship.
Systems like the Mk 110 CIGS and the Mk 46 were designed to more effectively combat a swarm threat.
The following is NAVSEA’s complete statement to USNI News:
At the time of DDG 1000 Critical Design Review in 2005, the MK110 (57mm) close-in gun system (CIGS) was selected to meet the DDG 1000 ORD Key Performance Parameter. The basis of that decision was the expected performance of the gun and its munition, coupled with desire for commonality in USN and USCG. Through 2010, various analysis efforts were conducted to assess the performance of potential cost-saving alternatives to the Mk 110 CIGS, for both procurement and life-cycle costs. The results of the analysis for alternative systems to the MK110 CIGS were not conclusive enough to recommend a shift in plan.
A follow on 2012 assessment using the latest gun and munition effectiveness information, concluded that the MK46 was more effective than the MK110 CIGS. Based on that assessment, approval was received to change from the MK 110 CIGS to the MK 46 Gun System. In addition to the increased capability, the change from MK110 to MK46 resulted in reduction in weight and significant cost avoidance, while still meeting requirements. DDG 1000 is planned to have two medium range MK46, 30mm Close-in Gun Systems that will provide a robust rapid fire capability and increased lethality against hostile surface targets approaching the ship.