CUVX Design Report - the AOE home page - Virginia Tech

CUVX Design – VT Team 2 Page 14optimized for this particular use. The structural characteristics are well known. Conventional monohulls have alarge residuary resistance at high speeds. The radar cross-section for a ship with bow flare and vertical or flaredsides may be significant. Compared to multi-hulls there is less usable deck area.• Wave Piercing Tumblehome MonohullThe Wave Piercing Tumblehome Hull form (WPTH) has negative flare for all sections of the hull above thewaterline. It is designed to penetrate waves, reducing the potential for slamming and extreme bow and sternaccelerations, and decreasing resistance in waves. The tumblehome hull form offers an inward-sloping ruledfreeboard to potential threats, minimizing RCS. Since the WPTH hullform is a monohull, the construction costwould be lower than multi-hulls of the same displacement. There is more large-object space than in multi-hulls ofthe same displacement.The negative flare reduces arrangeable volume and area high in the ship. Deck area is a particular concern forflight operations where the recovery and launch decks must be of sufficient size. Flare also provides an increasingrighting moment with heel; tumblehome exhibits the opposite, limiting the acceptable operational envelope toprevent capsize. Damage stability also suffers. The risk associated with this hull form is significant, since no largenaval WPTH has been built.Table 7. Hullform Advantages (+) / Disadvantages (-)LowRCSEndurance @Low SpeedLowCostResistanceat SustainedSpeedGood Large-ObjectSpacesRecoveryDeckGoodSeakeepingCatamaran - - ++ - ++ ++SWATH - - -- - - ++ +++SurvivabilityTrimaran - - ++ - ++ ++ +ConventionalMonohull+ ++ ++ + -WPTH +++ + + + + - + ?Modified-RepeatLPD-17+ + +++ ++ + +Table 7 summarizes the preliminary assessment of hull forms for CUVX. Based on this preliminaryassessment of hull forms, the conventional monohull, WPTH and LPD-17 mod-repeat hull forms were selected forfurther investigation and trade-off in Concept Exploration and optimization.3.2.2 Sustainability AlternativesSustainability characteristics for CUVX include endurance range, endurance stores duration, aircraft weaponsstorage, and aircraft fuel storage. A threshold value of 4000 nm is a typical minimum for surface-combatantendurance range. Auxiliary and amphibious ships typically have values closer to 12000 nm. These values are usedas the threshold and goal values, respectively. In the CUVX trade-off study, the values of 4000 nm, 8000 nm, and12000 nm are considered.Endurance stores duration is typically 60-120 days for naval ships. Values of 60, 90 and 120 days areconsidered for CUVX. CV 67 data is used to specify goals and thresholds for CUVX space required for aircraftammo and fuel. CV 67 is non-nuclear and more similar to CUVX than CVNs. CV 67 carries 49 aircraft, 609.6MT of ammo, and 3353 MT of fuel. CV 67 aircraft ammo and fuel weights per aircraft are: 12.4 MT for ammo and68.4 MT for fuel. The CUVX threshold value for ammo storage was determined to be 5 MT/UCAV and the goalvalue 15 MT/UCAV. The threshold value for fuel was determined to be 30 MT/UCAV and the goal value 60MT/UCAV.3.2.3 Propulsion and Electrical Machinery Alternatives3.2.3.1 Machinery RequirementsBased on the ADM and Program Manager guidance, pertinent propulsion plant design requirements aresummarized as follows:General Requirements - The propulsion engines must be non-nuclear, grade A shock certified, and Navy qualified.The machinery system alternatives must span a total power range of 40000–80000 SHP with total ship service++++