Διαδικτυακή Κοινότητα Φοιτητών ΕΜΠ

και βρηκα και πως επιπλεει
Αυτο ειναιι SWATH (Small waterplane area twin hull)

googlisious

Sea Shadow (IX-529) is an experimental stealth ship built by Lockheed for the United States Navy to determine how a low radar profile might be achieved and to test high stability hull configurations which have been used in oceanographic ships.

Ορίστε ρε παιδιά stealth είναι που μου λέγατε ότι δεν είναι stealth!!! Μα το θεό είναι σαν F-117 Nighthawk που του λύγισαν τα φτερά προς τα κάτω!!!

Οντως...αλλα ρε παιδια...εσεις που ειστε και πανεπιστημονες...η τεχνολογια στελθ δε βασιζεται στη μη αντανακλαση των κυματων των ρανταρ λογω γεωμετριας του σκαφους;αυτο πως αναθεμα δεν τα αντανακλα!;!;

f117-night hawk

ΓΙα να σε "δει" το ρανταρ, πρεπει να σημα να ανακλαστει προς την ιδια κατευθυνση απο την οποια ηρθε, πισω στο ρανταρ δηλαδη.

Στη θαλλασσα ας πουμε τα ρανταρ ειναι επιγεια. Μια τετοια γεωμετρια λοιπον το αντανακλα κατακορυφα προς το υπερπεραν ( ) το σημα, οποτε το ρανταρ δε λαμβανει τιποτα.

Γι αυτό οι έξυπνοι χρησιμοποιούν:

Απ το στομα μου το πηρες!(οχι δε του παιρνα τσιμπουκια μην αρχισετε:Ρ:Ρ:Ρ:Ρ)

Enositis21 wrote:και βρηκα και πως επιπλεει
Αυτο ειναιι SWATH (Small waterplane area twin hull)

Αναρωτιέμαι ποια είναι τα + και - της κάθε μεθόδου πλεύσης! Θα μάθω μόλις ξεκινήσει το μεταπτυχιακό!

A Small Waterplane Area Twin Hull, better known by the acronym SWATH, is a twin-hull ship design that minimizes hull cross section area at the sea's surface. Minimizing the ship's volume near the surface area of the sea, where wave energy is located, maximizes a vessel's stability, even in high seas and at high speeds. The bulk of the displacement necessary to keep the ship afloat is located beneath the waves, where it is less affected by wave action. Wave excitation drops exponentially as depth increases (Deeply submerged submarines are not affected by wave action at all). Placing the majority of a ship's displacement under the waves is similar in concept to creating a ship that rides atop twin submarines.

Variations
Basic Catamaran

2 main types of catamaran exist: the regular catamaran and the open catamaran, which features a trampoline between the hulls instead of plating.

The normal catamaran multihull, powered or not, consists of two Amas separated by two Akas, which may suspend a platform or trampoline between them. They can be of various sizes and recently, have become very large.
[edit] Pontoon boat or hydroairy ship
Main article: Pontoon (boat)
Hydroairy or Pontoon type

The hydroairy ship appears to be nothing more than an upgraded and enlarged pontoon boat with a formed and shaped underplatform. The general architecture is identical, consisting of two flotation chambers, for the Amas, joined by a load carrying platform, which carries the superstructure.

Invented in 1952 by a Minnesota farmer,[7] in the rural town of Richmond, MN. Ambrose Weeres had an idea that if you put a wooden deck on top of two columns of steel barrels welded together end to end, you would have a sturdy deck that would be more stable on a lake than a conventional boat. This was Ambrose Weeres, walking the same idea paths as the early Polynesians, while proving that the ideas behind the multihull are not all that counter-intuitive.

These sorts of boats are cheap and easy to make, require no ballast, and thus have good performance. Although this design is almost exclusively restricted to power boats, it is still essentially a catamaran. No displacement is lost towards ballast, therefore yielding huge operational efficiencies.
[edit] SWATH
SWATH type

The Small Waterplane Area Twin Hull (SWATH) is a hull form used for vessels that require a ship of a certain size to handle in rough seas as well as a much larger vessel. An added benefit is a high proportion of deck area for their displacement—in other words, large without being heavy. The SWATH form was invented by Canadian Frederick G. Creed, who presented his idea in 1938 and was later awarded a British patent for it in 1946. It was first used in the 1960s and 1970s as an evolution of catamaran design for use as oceanographic research vessels or submarine rescue ships.

Catamarans provide large, broad decks, but have much higher water resistance than monohulls of comparable size[citation needed]. To reduce some of that resistance (the part that generates waves), as much displacement volume as possible is moved to the lower hull and the waterline cross-section is narrowed sharply, creating the distinctive pair of bulbous hulls below the waterline and the narrow struts supporting the upper hull. This design means that the ship's floatation runs mostly under the waves, like a submarine (the smooth ride of a sub was the inspiration for the design). The result is that a fairly small ship can run very steadily in rough seas. A 50-meter ship can operate at near full power in nearly any direction in waves as high as 12 meters

The S.W.A.T.H. theory was further developed by Dr Thomas G. Lang, inventor of improvements to the semi-submerged ship (S3) in about 1968. Basically, a SWATH vessel consists of two parallel torpedo like hulls attached to which are two or more streamlined struts which pierce the water surface and support an above water platform. The US Navy commissioned the construction of a SWATH ship called the 'Kaimalino' to prove the theory as part of their ship research program. The Kaimalino has been operating successfully in the rough seas off the Hawaiian islands since 1975.