23 Feb 2023 08:56:38 0000018739 00000 n Answers must be in-depth and comprehensive, or they will be removed. by eddyhops Wed Feb 22, 2012 2:35 am, Post Accept Read More, What Makes Zumwalts Tumblehome Hull So Special. With the advent of gunpowder, extreme tumblehome also increased the effective thickness of the hull versus flat horizontal trajectory gunfire (as any given width material grows effectively "thicker" as it is tilted towards the horizontal) and increased the likelihood of a shell striking the hull being deflectedmuch the same reasons that later tank armour became sloped. "When you talk with officers inside the Navy, there is a lot of trepidation over this ship," said Bob Work, a military analyst with the Center for Strategic and Budgetary Assessments, a Washington think tank. "We can operate safely in Sea State Seven and Eight," Syring said. by RodeoClown Wed Feb 22, 2012 4:31 am, Post The same hull form is the preferred option for a new class of missile cruisers, dubbed CG(X). This is an area of hull dynamics that is rarely discussed, but dependent on the shape of the topsides, as a boat heels the vertical center of gravity moves both vertically and horizontally relative to the center of buoyancy at any given heel angle. 0000110422 00000 n Due to stability concerns, most warships with narrow wave-piercing hulls combine tumblehome with multi-hull designs, such as the Type 022 missile boat. Draft: 2 ft. Dry Weight: 10,200 lb. Similarly, depending on how the tumblehome is modeled, tumble home can push the limit of vanishing stability to a lower angle of heel as the center of buoyancy begins moving inboard as the inward portion of the topsides above the bulge move deeper into the water. Can someone post a picture or describe tumble home. by Cheeks Tue Feb 21, 2012 9:37 pm, Post On the DDG 1000, with the waves coming at you from behind, when a ship pitches down, it can lose transverse stability as the stern comes out of the water and basically roll over.". "Scientists are people who build the Brooklyn Bridge and then buy it.". How accurate is it? by TNbound Wed Feb 22, 2012 1:38 pm, Post As noted, much has been made of the ship's tumblehome hull design and its perceived lack of stability. Although top Navy officials uniformly express confidence in the DDG 1000, there is no shortage of doubters within the service. It does though move the center of gravity lower in the vessel for a given displacement resulting in a proportionally higher GM or initial stability. However, have it ever crossed your mind why Zumwalt class is built with a tumblehome hull? Welcome back with us again today on another episode at this channel. But several Russian battleships sank after being damaged by gunfire from Japanese ships in 1904 at the Battle of Tsushima, and a French battleship sank in 90 seconds after hitting a mine in World War I. Also rented a golf cart - pretty handy to zip down to the store and back. What do all you experts have to say? The exterior walls slant inward from the base to the top. Douglas Wipper, a former director of the National Canoeing . Tumblehome allows the advantages of a wider boat - stability, water shedding - without the disadvantage of the paddle shaft being pushed way off the boat centerline by the outside gunwale. 0000004450 00000 n the disappearance of tumblehome on battleships was about the same time as the appearance of the dreadnoughts IIRC, where we can see very different arnament, engines and armour defining the ships design. Ideally, a boat does not change trim, or roll down or roll out as it heels. These two factors mean that more weight can be devoted to the ship's main belt armour, or to armament. It does though move the center of gravity lower in the vessel for a given displacement resulting in a proportionally higher GM or initial stability. Technological advances have improved the capability of modern destroyers culminating in the Arleigh Burke (DDG 51) class replacing the older Charles F. Adams and Farragut class guided missile destroyers. Both the French and Russians eventually dropped the hull form. The dimensions of the DDG-1000's seven-level deckhouse are approximately 160 ft long by 70 ft wide by 65 ft high (48.8m by 21.3m by 19.8m). Thanks for all the answers, I got the idea that Tumblehomes were bad from the wikipedia article on the subject and I now see that it was very flawed. Officials from both contractors deferred to the Navy when asked about the design. Writer on Defense and Security issues, lives in San Francisco. Navy officials and engineers insist the design is safe, and point to extensive testing using computers and a variety of scaled-down models that have sailed test tanks and coastal areas such as the Chesapeake Bay. Firstly, it reduces deck area, which means that a lower weight of deck armour is necessary. Suggestions that the ship would capsize are "not true. Was that part of the reason for late adoption of superfiring turrets, especially in some navies? In the 1880s and 90s, naval architecture was more an art than a science. 0000001020 00000 n Especially the green water of tumblehome hull is different from that of hulls with flare free board. Create an account to follow your favorite communities and start taking part in conversations. Norman Friedman, a naval consultant and author of a series of design histories on naval warships, said, "This thing has a very good potential for causing a lot of problems. The sharply reduced crew size of just 182 promises operational cost savings and instant response, but automated damage control mechanisms coordinated by software remain an unproven option. "We've done all the modeling and testing to convince us that this is a great hull form.". The tumblehome hull forms a design in which hull slopes inward from above the waterline. Tumblehome designs also have some improvements in seakeeping over a conventional flared design. The Navy is analyzing potential alternative designs now for the cruiser, which is to carry a heavier, more powerful radar and more missiles than the Zumwalt. The chief advantage comes from the fact that the sides of the hull are angled away from the waterline. A ship model tank test means high cost and it takes a remarkable time to carry out experiments. Another advantage of a tumblehome is that enemy warships are kept as far away as possible, due to the broad distance covered by the ship's convex sides. The Yamato for scale is not my own, I just placed it there for scale. That means if your stability goes wrong at the wrong time and you find out you've got a software problem, you begin to submerge. This is achieved by shaping the bow and stern with a slight flare to direct water away. General General Discussion, Users browsing this forum: No registered users and 6 guests, The team | Delete all board cookies | All times are UTC. Tumblehome has been used in proposals for several modern ship projects. Its long, angular "wave-piercing" bow lacks the rising, flared profile of most ships, and is intended to slice through waves as much as ride over them. In modern days forward swept bows are used so the anchor is far enough forward not to be dropped on the sonar assembly under the water line. The term is also applied to automobile design, where a vehicle's sides taper inward as they go up. The hull consists of an outside covering (or skin) and an inside framework to which the skin is secured. Could you elaborate as to tumblehome liabilities in these areas? So lately I have been working on a huge battleship that just so happens to use a Tumblehome design. The much-analyzed Tumblehome hull is a smooth, stealthy, linear type of hull engineered to slice through the waves. And I'm giving short shrift to the discussion of form stability versus ballast conditioned stability. Or an adult toy, 1600 Ton Master, 2nd Mate Unlimited Tonnage. Is Russias Only Aircraft Carrier Cursed? Boat Design Net does not necessarily endorse nor share the view of each individual post. Despite being saddled with a two-year delay largely due to cost overruns, delays, and technical problems, the next-generation ship is expected to enter service in mid-2024. Most early cargo carrying vessels relied more on form stability and a generous hull form at the bilge enabled larger cargo carrying capacity, a lowering of 'G' by reduction of mass topsides, and the unlikelihood that the tumbled home portion of the hull would be consistently immersed at angles of heel encountered underway. At least eight current and former officers, naval engineers and architects and naval analysts interviewed for this article expressed concerns about the ship's stability. I may be wrong - I often am - but I think think tumblehome actually acts as a scoop and brings more water in. by Bob P Wed Feb 22, 2012 12:58 pm, Post All the tests are successfully confirming the tank testing and design analysis we've done. Gear-obsessed editors choose every product we review. We may earn commission if you buy from a link. The three rotation motions of a vessel- pitch, roll, yaw. However, the design has serious issues with survivability. the tumblehome hull design is used on a modern warship, as well as the benefits from using an innovative and modem tumblehome hull design. When you purchase through links on our site, we may earn an affiliate commission, which supports our community. Most evident in solo designs. So what are/were the benefits of this hull shape? The design includes a vertical stem line. Tumblehome is a term describing a hull which grows narrower above the waterline than its beam. US NAVY DDG 1000, Tumblehome Hull Zumwalt (photo phisicalpsience.com). "If the ship were to go dead in the water in those high sea states, the bow points into the sea and you can ride there all day because of the nature of the hull form," Syring said. Some say that a reverse bow "looks fast," but I personally believe that we generally grow to like the look of any feature that finally proves itself and performs well. 0000014703 00000 n When you talk about a stability curve for a boat with moderate tumblehome, the modeling of the hull below the waterline and in particular area just below the maximum beam becomes very critical as this controls whether the boat builds stability progressively or whether the boat simply flops over until fetching up against the bulge in the curve lurching to a halt as the stability builds. (U.S. Navy photo by . By rejecting non-essential cookies, Reddit may still use certain cookies to ensure the proper functionality of our platform. An extreme tumblehome shape can make a canoe a little less stable when leaning, but generally a slight tumblehome shape doesn't affect stability much at all. "It is very mature at this point.". Righting arm is reduced with increased immersion/increased heel. n. 1. Zumwalt, on the other hand, handled conditions better than most ships its size. JavaScript is disabled. The RPK-74 Light Machine Gun Is Far Deadlier, U.S Navys MQ-25 Stingray Unmanned Tanker. Tumblehome designs have difficulties operating in bad weather, with a considerably higher risk of capsize than a flared design. New to this category is the Zhaochang patrol ship, purpose-built for long-distance fisheries enforcement with a new tumblehome hull design and a 30 . On a recent mission to Alaska, it is confirmed the designs superiority, countering critics who believed early on that the Zumwalt would be less seaworthy than previous design. This allowed French ships to combine heavy gun turrets with sufficient freeboard, and their designs proved quite seaworthy when the Russian Baltic Fleet transited to the Pacific in the Russo-Japanese War. Steep spots in the curve (rapidly increasing stability) typically mean that somewhere there is a flat spot (a place where stability levels off or decreases rapidly). DDG 1000 has a 'tumblehome' hull form, a design in which hull slopes inward from above the waterline. This design increases load capacity, while still being easy to paddle. The shape was popular among French naval designers in the late 19th and early 20th centuries, and a number of French and Russian battleships short and fat, without any wave-piercing characteristics were put into service. ", "The Navy would say it has tested the software thoroughly and knows exactly what it is. But at some point I plan to do a proper drawing and a higher quality 3D model. "All these things can get a little confusing," concludes Mann . [1] Flare can also induce instability when it raises the center of gravity and lateral torque moment of a vessel too much (by negatively impacting its righting moment and metacentric height ). Syring and Fireman bristled at suggestions the tumblehome hull would be in danger should the ship lose power or control in high seas. That said, there are some major advantages to adding deadrise to a hull: The V-shape helps the boat cut through waves while minimizing impacts Deadrise helps a boat bank into turns V-hulls often throw less spray However, having all that V-shape in the hull does also introduce some disadvantages into the mix. My plan is to reign in the design, then make a shipbucket, then make a better 3d model in Rhino 3D (right now its in Sketchup). Tumblehome is a term describing a hull which grows narrower above the waterline than its beam.The opposite of tumblehome is flare.. 5482 0 obj <>stream Unlike most contemporary warshipsor any ships for that matterthe Zumwalt uses a so-called tumblehome hull. Public discussion of the shape largely ended when the Northrop team was picked. Why Is a Russian Spy Ship Lurking Near Hawaii? This will tend to reflect radar energy that is directed towards the ship from another up into the The new form design makes the ship have many special hydrodynamic performances. Older warships had loads of it -- was that about gunnery, or sailing? %%EOF The vessel with 14,500 tons is a multi-function class that was built with a primary purpose of naval gunfire support and secondary roles of surface and anti-aircraft warfare. Steel warships especially of the early 1880s frequently demonstrate tumblehome, though it has been an influential factor in their design ever since their beginnings. This faceted appearance is a common application of the principles of stealth aircraft. The result is a ship that looks like a knife cutting through water, giving it a sleek, stealthy look. http://www.naviearmatori.net/albums/userpics/15767/Le_Redoutable_(1889).jpg. The drawing here (done by Mann at Power & Motoryacht's request) illustrates what he thinks are the several aspects of design that make for a true Carolina-type sportfishing boat, namely flare, flam, S-frame (or S-curve, a hullside design element), and extreme tumblehome. Low freeboard fenders sit high on the hull and hang inward over the gunwale. Some people have criticized the Zumwalt tumblehome hull, because it lacks these features. The Zumwalts Shape Helps It Handle Rough Waters, U.S. Navy photo by Mass Communications Specialist 2nd Class Jonathan Jiang. ", "What I'm trying to find out is what speeds do we want to avoid in those sea states," Syring said. Normal approximations of sea keeping characteristics using linear differential equations In addition, the streamlined, wave-piercing tumblehome hull of the warships has a "knife-like profile," which provides the 600-foot-long vessel with the radar signature of a fishing boat. But the concerns from current surface warfare officers have not persuaded Navy leaders to re-evaluate their position, he said. . Nothing like the Zumwalt has ever been built. "You mean this?" By the same token, the narrow deck line associated with tumblehome can reduce the initial force needed to start to right an inverted boat however, depending on how the tumblehome is shaped, it can also increase less significant ultimate force required to right the boat. Depending on the shape of the hull, some boats actually move lower into the water and are said to roll down. 0000136350 00000 n This can have a negative impact on maintaining a straight course as the hull shape change in the water causes the boat to want to 'roll steer' or in other words develop a tendency to change course solely because of the heeled shape of the hull in the water independent of all other factors which may otherwise cause a boat to alter course as it heels. This design features the famous Carolina flare, broken shear and tumblehome that is sure to turn heads. The Navy May Use One Hull Design To Replace Its Cruisers And Some Destroyers. One former flag officer, asked about DDG 1000, responded by putting out his hand palm down, then flipping it over. Interesting thread, but I have no idea of what you are talking about. 0000009269 00000 n Tumblehome hulls haven't been seen on naval ships in over a century. 0000135757 00000 n Traditional designs tend to remain pretty neutral with regards to heel, but designs with tumblehome tend to initially roll out, before rolling down, sometimes quite deeply. by Cheeks Wed Feb 22, 2012 3:51 am, Post Board index "It's never been to sea before, and that obviously brings in a certain amount of risk," he said. In expressing their confidence in the design, Navy officials said that recent meetings and reviews have concentrated on other technology areas and not addressed any concerns with the ship's configuration. This 3d model is to just help me with placement and scale. "It all comes down to engineering and science," he said. Tumblehome is a complex issue to explain in detail. UxS IBP 21 integrates manned and unmanned capabilities into challenging operational scenarios to generate warfighting advantages. Other professionals would prefer to see the hull validated by an independent study group before the Navy commits to building ships. The hull form in combination with choice of materials results in decreased radar reflection, which together with other signature (sound, heat etc.) Both flare and tumblehome may be built into different parts of the same hull. The ship's induction motors generated a whopping 58 megawatts of electricity while cruising, enough to power the entire 17,630-ton ship thanks to an Integrated Power System. There's nowhere left to go with the Arleigh Burke design, meaning the service will have to find a new ship to meet . It appears that by doing so the boat retains less water when executing a roll and potentially it is drier when running through river features. But he admitted that there is a crucial problem with his idea. 0000140477 00000 n We enjoyed everything about our stay - rented the pontoon boat and fished for a day with a shore lunch that we packed ourselves. "We feel very confident in the hull form," said Allison Stiller, the deputy assistant secretary of the Navy for ship programs. The streamlined, wave-piercing tumblehome hull has a "knife-like profile," which provides the 600-foot-long warship class with the radar signature of a fishing boat. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more! This significantly reduces the radar cross-section since such a slope returns a much less defined radar image rather than a more hard-angled hull form. But you have to worry about conditions where software hasn't been written correctly. This includes a roof tapering in, and curved window glass. by pblanc Tue Feb 21, 2012 11:48 pm, Post 0000003811 00000 n The house and stable are unique examples and similar to wooden water tower construction with flared supports for added strength. It cannot be denied that the USS Zumwalt, with its knifelike bow, is more stable in stormy weather than other destroyers and cruisers. 2 In early operations the ship displayed good sea keeping, even at high speeds, and very good vertical and axial stability. "Stealth was BS to start with and is still BS.". Tumblehome designs have some major advantages for battleship designs. The ship's form was conceived in the mid-1990s as the ultimate stealth ship exceptionally hard to find using conventional radars and search systems. Comparative model experiments show that a ship fitted with a bulbous bow can require . ", Still another naval analyst said the problem is worse than that: "It is inherently unstable.". The long deep and narrow fore portion of the hull resembles an axe. Actually tumblehome was a means to strengthen the hull. Reddit and its partners use cookies and similar technologies to provide you with a better experience. Forcesproject.com Having the ability to handle severe conditions better than most ships its size, the U.S. Navys newest warship, USS Zumwalt is reported to quickly rights itself in rough waters, faster than other designs. Since the interior walls are straight, the transition takes place in the exterior windows and doors which are wider at the bottom than they are at the top. Over the next few years, the Borodino class of battleships was constructed in Russian shipyards, using a modified version of the Tsesarevich design. "In conventional hulls, we have done more with model testing and design work. The ship's Raytheon AN/SQQ-90 integrated undersea warfare system includes AN/SQS . With a relative location of the steering stops, the size of the propellers and the stability of its so-called tumblehome design, it seems that Zumwalt-class destroyers appears to be one of the Navys most comfortable rides. . "Those folks are genuinely interested and passionate," he said. In the days when mainsail booms and mainsheets hung over the transom, and fishermen hauled nets and traps over the side, the rounded corners of an ellyptical transom kept lines from getting hung up on the corners of the transom. Define tumblehome. .css-v1xtj3{display:block;font-family:FreightSansW01,Helvetica,Arial,Sans-serif;font-weight:100;margin-bottom:0;margin-top:0;-webkit-text-decoration:none;text-decoration:none;}@media (any-hover: hover){.css-v1xtj3:hover{color:link-hover;}}@media(max-width: 48rem){.css-v1xtj3{font-size:1.1387rem;line-height:1.2;margin-bottom:1rem;margin-top:0.625rem;}}@media(min-width: 40.625rem){.css-v1xtj3{line-height:1.2;}}@media(min-width: 48rem){.css-v1xtj3{font-size:1.18581rem;line-height:1.2;margin-bottom:0.5rem;margin-top:0rem;}}@media(min-width: 64rem){.css-v1xtj3{font-size:1.23488rem;line-height:1.2;margin-top:0.9375rem;}}Is Russias Only Aircraft Carrier Cursed? As a result, it can create a wider beam that can accommodate additional systems. The senior surface warfare officer noted numerous discussions among other surface warfare officers about the somewhat dismal history of tumblehome ships. USS Cyclops Is the Navys Last Missing Big Ship. The Fora platform includes forum software by XenForo. As long as you don't go overboard with it and end up looking like a beer can floating on its side. [1] Now its captain is speaking out about how it handles high seas. In the ensuing battle, three ships of the class would be sunk.