Analysis: Will the USS Zumwalt Capsize in Stormy Seas?

| March 1, 2020


DDG-1000 USS Zumwalt

The Navy’s most advanced ship, USS Zumwalt, is scheduled to enter service this month. The stealthy design, with the unique “Tumblehome” bow, designed to slice through waves, was the source of much discussion. How would the vessel do in heavy seas?
Quite well, thank you. During sea trials in the Gulf of Alaska, famous for foul weather, the ship encountered Sea State 6 conditions, described by the World Meteorological Organization as “very rough” with wave heights of 13 to 20 feet.
From the article:

By Kris Osborn

(Washington, D.C.) When faced with high winds, up to 20-foot waves and dangerously rough seas — which Navy ships can survive? … and continue to wage war on the open sea?

Would the new stealthy USS Zumwalt destroyer capsize or suffer extreme damage if its wave-piercing Tumblehome hull were subject to massively dangerous stormy sea conditions?

Such questions, often put to the test with new ships during “sea-trials,” were of particular relevance with the Zumwalt, as it is a first-in-class high-tech warship built with a sleek, more linear, stealthy hull. There have been persistent questions as to whether the ship might have stability problems in dangerous sea states, given that it does not have a standard “flare” shaped ship hull used by most destroyers and carriers. Rather, it has a thinner, sharper, smaller wave-piercing hull intended to increase stealth, maneuverability and speed.

The answer, according to the Commanding Officer of the USS Zumwalt Capt. Andrew Carlson, is that the ship has remarkable, if even somewhat surprising, stability.

“We took advantage of a Gulf of Alaska storm which reached Sea State 6 conditions. We were able to drive around in that at full power.” I had some hesitations and I knew the ship rode differently, but I would rather ride this ship in heavy seas,” Carlson said recently during a presentation at the Surface Navy Association Symposium, Arlington.

Carlson explained that, while the rough seas were as always nerve-racking, the ship seemed to “come back” from a roll caused by extremely rough seas. He said that during the heavy storm, “green water waves were coming up on the bow.”

“You get used to the roll period. It is short. If you are working on top on a cruiser in rough seas, you wonder if you are going to come back (roll back flat in rough seas). With Zumwalt, we don’t experience that. You get used to finer oscillations,” Carlson said.

Pretty amazing. Read the article and watch the video here: Defense Maven

Category: Navy

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The Other Whitey

Tumblehome hulls are inherently stable in rough seas, according to my understanding. This is why it was the standard hull form for the tall ships of yore. The problem is when you start blowing holes in the side and letting water in. That’s when tumblehomes suddenly become very, very unstable, much more so than other hull shapes, and wind up doing HMS Captain impersonations.

Jan K

Naval architecture is definitely a complex field, but there are a few things that one can make sense of. Think of a conventional hull shape, flaring outwards: when the ship heels (leans over, whether owing to wave action or wind blowing against rigging or superstructure), the hull on the lower side gets pushed more and more into the water. This increases flotation on that side, by sheer displacement of water. This increases righting moment – the push that gets the vessel back upright. On the other hand, it also means that you have more mass on a longer lever arm, thus increasing the rotational momentum of the vessel, slowing both the original roll and the return roll. An additional complication, depending on configuration, sea state and degree of heel, is that the deck and deck edge can hydrodynamically tend to dig into the water, and hold back the return roll. It’s all very complex, which is why naval architects have to be seriously qualified. In a vessel with strong tumblehome, it’s more like floating a tube (there’s more to it than that, but let’s go with that for now). Less mass on a shorter lever arm means les resistance to both initial and righting roll, but it also means less resistance to the initial roll – which in a rough sea state means that waves which, under a flared hull, would normally lift that side of the vessel, now have nothing they’d be lifting and actually have less influence on the vessel’s roll. The flared bow is different from the flared side, because the bow hydrodynamically affects the ship’s progress through the water. Pitching can increase quite dramatically with a flared bow going through a heavy sea, because that flare catches every wave and lifts the vessel’s bow every time. On the other hand, a tumblehome that goes all the way to the bow will have some hydrodynamic tendency to force the bow down – but that is counterbalanced by the part of the hull that you don’t see, which provides hydrodynamic lift. The question is which one predominates, and… Read more »

Jan K

Understood and appreciated, sir.

I apologise for the faux pas; thanks for fixing it for me.

Not a veteran, but I appreciate you all, so I just feel a little happier when I can add something.

Sparks: if you want to learn vast quantities by osmosis, look for anything written by Phil Bolger on the topic.

Sparks

Jan K, Thank you for the detailed information. Being one who is mesmerized by all things naval (though never in the Navy myself) I understand far more now than before.

You as well AW1Ed, thanks.

5th/77th FA

My knowledge of Naval Vessels is limited to (a) they make wonderful Floating Artillery Platforms, (b) they are an excellent sea mobile Aerial Artillery Platform delivery system, (c) they are good transporters of troops and material in about seven locations, and (d) they work better when the water is on the outside.

Some folks scratched their watches and wound their butts when the FIRST USS Monitor and CSS Virginia (Merrimack) Class of ships came along. The Zumwalt Class is just technology continuing the advance. I think that our Armed Forces should have the best available to do their jobs.

Slow Joe

I don’t know what we are doing building obsolete ships.

The weapon of the future is the drone. We should be building drone carriers for air, surface and underwater drones.

Jeff LPH 3, 63-66

Zumwalt, the knucklehead who had E-1 through E-7’s wearing a chiefs uniform.

Sparks

I think officers in whites, should have to wear the dixie cups. Only fair.

Cameron K.

I remember seeing that uniform in The Towering Inferno where a Navy Chief and a Petty Officer (either a Second or First Class, I can’t remember which) arrive to began air lifting survivors and the Petty Officer was wearing that exact uniform.

The Other Whitey

Smooooooooooooke on the water!

Even when it’s not on fire.

Hondo

I think he’s referring to the Kuznetsov that’s so unreliable that it’s generally accompanied by an ocean-going tug on deployments in case it breaks down.

https://en.wikipedia.org/wiki/Kuznetsov-class_aircraft_carrier#Reliability

Martel

The Zumwalt Class literally is kitted out with guns it doesn’t have ammo for. Also failed sea trials, in kind of a big way.

We just going to ignore this?

Martel

Soo… if it’s us, it’s “growing pains.” If it’s exactly the same thing, but with another country, it is comedy, and they are just lame?

Hondo

Invalid comparison, amigo.

The Kuznetsov has supposedly been “fully operational” since 1995 – or for roughly 25 years. And that didn’t happen until about 4 years after it was commissioned in 1991.

Comparing that with a new ship class of a novel design, the first ship of which has been commissioned <3 1/2 years, is a stretch if not complete BS.

Martel
Martel

Confused. Russian ship needs a hand, and they are 3rd world. US navy needs assistance, and that’s just “issues.” Woukd appreciate your standards before I comment further. Thanks.

Hondo

Gee, a ship had issues <2 months after commissioning.

This is news? C'mon, Martel – you're really stretching the limits of credibility by using that example. Is that the best can do?

Martel

I’m “flinging poo” by being respectful, and pointing out fact?

Screen shots have been saved. Enjoy social media fame.

Martel

29 ordered. 3 built. 2 on active service.

Mmmm….

Hondo

Yeah, that’s a problem. And it’s self-inflicted. This is yet another example of DoD – likely under Congressional pressure to reduce costs – cutting procurement quantity of something to “save $$$”. The near-universal end result of ding that is that the unit cost goes through the roof. Often, you’d be financially far better off admitting failure and starting over from scratch, using lessons learned from said failure. The rounds for the AGS were developed (at high R&D cost) under the expectation that 32 such ships would be produced. Unfortunately, the Navy is terminating production of the Zumwalt class of destroyers at 3. The original goal for a per-round cost was $35k. I’ve read that about $85k/round was later determined to be more realistic – but that was also based on production of ammunition for 32 ships using the system, not 3. The reduction in ships using the system means <10% of the rounds originally planned will be procured. If you have a huge R&D bill to recover, this means you have to recover those R&D costs over <10% as many units produced – which in turn raised the price of the round by a factor of 10 or so, from $85k to around $1M each. Why? Because economies of scale in production never materialize. Simplest interim solution – and one which I predict may well eventually be adopted by the Navy – would be to "bite the bullet" (intentional pun) and modify the AGS to use the Army's M982 Excalibur (and conventional 155mm rounds, if possible) as an interim measure. Unfortunately, this will require a $250M modification to the existing AGS, magazines, and Zumwalt-class ships produced to date – and, unfortunately, would also require "Big Navy" to admit it made a mistake. Navy pride and the "not invented here" syndrome may well make that common-sense solution impossible. Why someone didn't plan the M892 (or for the use of conventional 155mm ammo, for that matter) as a "fallback" in case the original AGS rounds turned out to be unusable for whatever reason is a damn good question. IMO that should have… Read more »

Martel

Might of been 2, or even 3 years ago…But care to make the ship, and which country owned it, that got stuck because of ice up in Canada?

Hint: Wasn’t Rusian.

Martel

*fat thumb edit.

*Russian.

Hondo

Oct 2018, actually – <18 months ago. And while in May 2019 a workaround was announced, that workaround was expected to take at least 1.5 years to finish the work.

It's likely going to take quite a while longer, though. Less than three months ago, a major fire apparently broke out on the Kuznetsov while it was being repaired. The fire killed 2 and injured 14.

The LCS that got stranded in Montreal last winter was embarrassing, yes – but that incident hardly compares to a ship that needs to be followed around on deployments by an ocean-going tug because it’s not considered reliable enough to make it back to home port when it deploys.

Martel

Please see my post about the Zumwalt breaking down in the Canal Zone, and needing a tugboat to rescue it.

Thank you.

Hondo

See my reply below. This is yet another invalid comparison. Very different situation, both in terms of inherent reliability and ship’s age (a ship several years old is expected to be more reliable than one <2 months after commissioning).

Methinks you have nothing, Martel. You're grasping at straws by using invalid comparisons that are simply not credible.

Martel

So,a ship several decades old that needs assistance is a dumpster fire, but one 3 months old that needs assistance isn’t? Your words, not mine. Thank you for your insight.

Hondo

Exactly – and if you understood a damn thing about how systems are actually developed and fielded, you’d know that already.

All new systems have issues immediately after they’re introduced into service. Something is always overlooked or “gotten wrong” during development.

Ships in particular are prone to this, because they’re large complex, designs. They tend to take months or years of “find/fix” to sort out unknown/undetected problems – particularly when they’re the first of a new class.

Honestly, I think you’re simply trolling here. Why don’t you be a good lad and (as the British might put it) bugger off. You’re adding nothing to the discussion here, and I think that’s by design.

Hondo

Yeah, but how many extra crew does it take before it will “become so overly populated that it will tip over and capsize.” I understand a certain Congresscritter from Georgia wants to know. (smile)

Hondo

Actually, a bit off here. 32 ships of the class were originally planned; the program was first cut to 24, then to 7, and then terminated at 3 ships.

You are correct that the third ship of the class has not yet been commissioned, but that’s about all you’re correct about above.

Like many recent DoD systems, the Zumwalt-class was IMO yet another case of “trying to do too much”. The end result often is that the resulting system is too costly to be procured in sufficient quantity to be operationally effective.

There never has been and never will be a perfect system. But DoD sure loves to spend tons of money trying to produce them when a 90% solution could be had at far less cost relatively quickly.

Martel

Thank you for the numbers correction. Much appreciated.

Doesn’t change the fact that this Class of ship, much like the latest “fighter”, is a POS.

Some people here just can’t handle that.

Martel

You and your buddy went straight to the name calling.

I’ve been respectful, factual, and humble when I was wrong.

Be a man and do the same.

Thank you.

Jeff LPH 3, 63-66

The embroided Zumwalt profile on a baseball cap can’t compare with those late 1940’s-1960’s tin can embroided cap profiles.

26Limabeans

Might keep sailing while capsized with that
giant keel already in place.

Deckie

If she has a low center of gravity (large GM) she may roll like a bitch. Wonder what her metacentric height is?

Hack Stone

They can design a stealth warship to withstand 20 foot waves, but they can’t design an airplane that can make it to Sisters Eagle Airport.