The USS Zumwalt is the latest multi-role destroyer in the Navy’s arsenal. The destroyer is designed to carry out surface missions, function as an anti-aircraft platform, and support ground troops with naval gunfire. It’s a guided missile destroyer with advanced systems that could one day support railguns or laser-based weapons and — as if that wasn’t enough — it’s actually stealthy enough that the Navy may modify it to make it easier to spot on radar.
The Zumwalt is considered exceptionally stealthy — at 610 feet long, it reportedly reads like a 50-60 foot fishing boat. If that doesn’t seem particularly impressive, imagine successfully disguising an NBA player as a toddler for Halloween. It’s a bit like that. In order to achieve its stealth profile, the Zumwalt is designed with a tumblehome hull, which narrows as it rises rather than flaring out. Tumblehome hulls were standard in wooden sailing ships for centuries and many of the ironclads and pre-Dreadnaught battleships featured similar lines. One of the odd things about the Zumwalt is how its hull actually recalls much older designs like the USS Atlanta, shown below:
Tumblehome hulls were abandoned after the Russo-Japanese in the early 20th century, when multiple Russian battleships that used the hull type were lost at the Battle of Tsushima in 1904. Tumblehome hulls of that era could become dangerously unstable if the ship took on water, though they generally exhibited excellent seagoing characteristics. The Navy has insisted that the Zumwalt hull architecture has been extensively tested and will have no problems in rough weather. It goes without saying that the ship is far more advanced than previous destroyers, much less the ironclads it resembles — even the gun mounts on the Zumwalt retract into housings that are shielded from radar.
Adding deflectors to a boat to make it less stealthy might seem to work against Zumwalt’s primary purpose, but there are safety issues to consider. In poor weather and limited visibility, a 610-foot ship that looks 50-60 feet long is a potential hazard to everything else around it. The current plan is to mount reflectors on the ship that will increase its radar signature and warn ships in the area that they’re closing on a large vessel, not a fishing boat. In wartime or when operating in unfriendly waters these reflectors can be quickly removed, restoring the Zumwalt’s stealth profile. Keeping the ship out of stealth mode save when necessary also means fewer potentially enemy vessels see its “native” profile in the first place, reserving the capability for when it’s needed.