tumblehome hull advantages

", But he still harbors doubts. 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. So famously the French built some [pretty](http://www.naviearmatori.net/albums/userpics/15767/Le_Redoutable_(1889).jpg) distinctive warships towards the end of the 19th century. 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. The hull widens as it nears the water, and at the bow at the waters edge is longer than it is on the main deck. PRICE CODE 17 18.SECURITY CLASSIFEA- TION CATIONOF REPORT Unclassified SECURITY CLASSIFI-OF THIS PAGE 19. 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. I have been trying to surmise the advantages and disadvantages of increasing tumblehome on a canoe. I feel like you would want to slope the armour and reduce the flat deck area by as much as possible, both to reduce plunging fire damage. The Fora platform includes forum software by XenForo. 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. As a result of this geometric characteristic, the tumblehome hull provides several advantages over conventional hulls, including the following: i) the wave-piercing bow is suitable for high speeds, and ii) a small radar cross-section (RCS) reduces detection possibility. The hull and rudder interaction coefficients, thrust deduction factor, inflow velocity to propeller, and inflow velocity to rudder are obtained in large drifting conditions using the measured . by ian123 Wed Feb 22, 2012 3:25 pm, Powered by phpBB Forum Software phpBB Limited. 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. The Portal for Public History. "To say [the ship is] inherently unstable in certain sea states, there are lots of caveats to that," Syring said. You know you have been following @TheDreadShips too long when you look at the Mercedes W14 and think, nice tumblehome hull there . "You mean this?" The S. A. . The 'tumblehome' hull forms a design in which hull slopes inward from above the waterline. There are no new questions here, however they've been around since the tumblehome configuration was adopted in the late 1990s. Tumblehome, historically, has problems in a following or stern quartering sea. Chief designers can completely change the styles used by a navy. What do all you experts have to say? Navy Unveils Next-Generation DDG(X) Warship Concept, WI the Imperial Japanese Warships of Operation Ten-Go was ISOT to the Battle of Jutland. "Frankly, the people best qualified to do it are the people already involved in the design and testing of the hull," he said. Five more are planned, far fewer than the 32 once envisioned. "It's never been to sea before, and that obviously brings in a certain amount of risk," he said. 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. Captain Carlson attributed the Zumwalts stability to hull form, relative location of the rudder stops, and the size of the propellers. 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. Wow, if I could I would love to commission you for making a 3D model of a battleship. Tumblehome is a term describing a hull which grows narrower above the waterline than its beam. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features Press Copyright Contact us Creators . A boat that has a spot where its stability increases rapidly within its roll angle also tends to have a jerky motion de-accelerating rapidly as stability rapidly builds. Firstly, it reduces deck area, which means that a lower weight of deck armour is necessary. Tumble home does not result in a loss of buoyancy until the tumbled home section is immersed. But fighting floods is more difficult without muscle power, and that worries surface officers. Go easy on me, Newbie hereConcave Hull design question Design Competition: Multi-Purpose E-Foiler. The Russo-Japanese War proved that the tumblehome battleship design was excellent for long-distance navigation, but could be dangerously unstable when watertight integrity was breached.[3][how?] We will begin this session by taking a look at the Zumwalt, formally known as DDG 1000, are a three-ship series of guided missile destroyers developed by the United States Navy. 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. 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. Another issue is they tend to be a bit wet, a flared hull blocks some spray from wave action near the waterline, a tumblehome doesn't as the waterline is visible from the weather deck. The Navy has built scale models to test the DDG 1000 design, including a 150-foot quarter-scale steel hull that was "extraordinarily stable," said one industry source. For example early IOR era boats have a bulge in their topsides that relates favorably increasing girth and also altering the apparent beam by distorting the hull at the points at which the beam measurement was taken. p54. Gear-obsessed editors choose every product we review. The U.S. Navys newest destroyer is a better ride in rough seas than other ships, thanks to the shape of the hull and other factors. In 1898 they ordered Tsesarevich from a French shipyard, building her to an upgraded version of the French Jaurguiberry design. Officials from both contractors deferred to the Navy when asked about the design. That curvature made the hull stronger than what a slab side would. 0000013074 00000 n For the tumblehome hull, an opposite trend is observed in both the experimental and numerical results. Although top Navy officials uniformly express confidence in the DDG 1000, there is no shortage of doubters within the service. With less of the hull contacting the water the vessel becomes laterally unstable, which might seem like a bad thing, but this instability allows for the hull to pivot along its length and managed to stabilize turning at high speeds. In more modern designs it was often about cheating some racing rule. "There's no requirement for stealth," said a retired senior line officer. One of the main issues with it is the stability, the more a hull rolls, ideally the buoyancy force acting against the force of the roll should increase the more the hull is inclined, with tumblehome, that peaks early due to the shape of the hull. Funny thingI was never attracted to those hull shapes Jeff shared a really interesting discussion of the design and performance aspects of tumblehome. "We're seeking to understand and quantify through our testing program the performance characteristics of the ship at extremely high sea states and heading position.". by ESP Tue Feb 21, 2012 9:05 pm, Post 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. But the reality is that no full-scale ship using the Zumwalt's configuration has ever put to sea and that worries many veteran naval architects, engineers and surface warriors. This also strongly reduces the ship's resistance to underwater damage. Critics of the Zumwalt -class destroyers have worried that the ship's design could lead to instability at sea. And why suffer the peril of an inherently instable hull form? The prospect of a new cruiser has reignited a debate over the need for stealth itself. True but historically Tumblehome was used before they had gun decks. The tumblehome has been reintroduced in the 21st century to reduce the radar return of the hull. Like every design question, it's a matter of trade-offs. 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. 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. It's also worth noting that the Navy and its shipbuilders have conducted extensive modeling and testing of the concept and insist the hull form is valid. Ellyptical tansoms are generally thought to have come into being strictly for pragmatic reasons. All ships may face dangerous conditions, he said. The hull form in combination with choice of materials results in decreased radar reflection, which together with other signature (sound, heat etc.) The tumblehome designs you highlight were created well before these issues were well understood. Interesting thread, but I have no idea of what you are talking about. Could you elaborate as to tumblehome liabilities in these areas? 0000128006 00000 n Experts offer their predictions. "A one-twentieth-scale, 30-foot scale model is undergoing testing," said Capt. Those concerns are unwarranted, the Navy insists. "We can operate safely in Sea State Seven and Eight," Syring said. Tumblehome designs have some major advantages for battleship designs. However, France in particular promoted the design, advocating it to reduce the weight of the superstructure and increase seaworthiness by creating greater freeboard. The Zumwalt reportedly quickly rights itself in rough waters, faster than other designs. Ten major technology areas, including the hull, are part of the DDG 1000 development project. 14 SUBJECT TERMS Tumblehome, Wallsided, hydrostatic, damaged stability 15. Discussion in 'Boat Design' started by econologica, Aug 20, 2006. does anyone know a technical naval architecture reason for this ubiquitous tumblehome in small runabouts? It deflects waves and resists capsize. As mentioned, the case could be made the timber ships of war had tumblehome in order to keep the weight of the heavy guns within the limits of the waterline, to allow the guns to be rolled out and fired even when ships we grappled together in close combat, and due to issues related to timber ship construction (the convex surfaces associated with tumble home meant that the seams were compressed rather than stretched open when exposed to high loads.). Its long, angular "wave-piercing" bow lacks the rising, flared profile. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more! the tumblehome hull design is used on a modern warship, as well as the benefits from using an innovative and modem tumblehome hull design. Zumwalt, on the other hand, handled conditions better than most ships its size. Was that part of the reason for late adoption of superfiring turrets, especially in some navies? There's nowhere left to go with the Arleigh Burke design, meaning the service will have to find a new ship to meet . 0000136777 00000 n The first of a planned 19 is to be ordered in 2011. ", Still another naval analyst said the problem is worse than that: "It is inherently unstable.". ", "These retired folks don't have the data that I have," Syring said. US NAVY DDG 1000, Tumblehome Hull Zumwalt (photo phisicalpsience.com). "If you're operating a million-watt radar, the question might be: Why invest in this hull in the first place? 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. Both bidding teams one led by Northrop Grumman, the other by General Dynamics presented virtually identical tumblehome designs, as dictated by the Navy's stealth requirements. USS Zumwalt undergoing sea trials in December 2015 (photo: en.wikipedia.org). Well, technically, one can initially see several reasons why these bows have become popular of late. Abstract The tumblehome hull adopts some novelty designs such as low-tumblehome freeboard and wave-piercing bow. 0000140477 00000 n Sponsored by Grammarly Grammarly helps ensure your writing is mistake-free. [4], Last edited on 15 February 2023, at 19:34, Learn how and when to remove this template message, "Frank Lloyd Wright Building Conservancy", Traditional Birchbark Canoes Built in the Malecite, Penobscot and Passamaquoddy style, DDG-1000 Zumwalt / DD(X) Multi-Mission Surface Combatant Future Surface Combatant, https://en.wikipedia.org/w/index.php?title=Tumblehome&oldid=1139565021, This page was last edited on 15 February 2023, at 19:34. The destroyer uses a unique "tumblehome hull" design. by TNbound Wed Feb 22, 2012 1:38 pm, Post [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 ). And the Navy shouldn't base CG(X) on the Zumwalt hull "until we get some experience with DDG 1000, or get a larger model where we can verify the performance of the hull," he said. As an addition to the above answers (ie stability, that are more important IMO). It allowed for maximizing a vessel's beam and creating a low center of gravity (by decreasing mass above the waterline), both tending to maximize stability. The tumblehome will affect rolling if you think the boat will roll lots or wish to use tumblehome to reduce rolling. This means that a tumblehome design is much more vulnerable to capsize. FLARE A flared hull widens out near the gunwales. 0000018739 00000 n But the doubts persist despite the Navy's declarations of confidence in the design. By angling the ship's main belt, it also increases the effective thickness a shell will encounter. 0000009269 00000 n It's great for fenders and lines so those items don't crowd valuable fish box or other storage." Mag Bay 33 Specifications LOA: 33 ft. 6 in. Interestingly, the Zumwalt, unlike other modern warships, has such a tumblehome hull. As such, a tumblehome design will be better armoured or armed than an equally-sized conventional design. Depending on the shape of the hull, some boats actually move lower into the water and are said to roll down. startxref The Navy expects to award construction contracts for the first two ships in May to Northrop and General Dynamics at a planned price of $3.3 billion each. We enjoyed everything about our stay - rented the pontoon boat and fished for a day with a shore lunch that we packed ourselves. We've taken it up through Sea State Eight and even Sea State Nine [hurricane-force seas and winds] in some cases to understand the hull. If all the critics are right, this thing is dangerous. Nothing like the Zumwalt has ever been built. By rejecting non-essential cookies, Reddit may still use certain cookies to ensure the proper functionality of our platform.