Preliminary Concept for a Panamax 38 kt Passenger Liner

Discussion in 'Boat Design' started by OceanLinerFan, Jul 18, 2017.

  1. OceanLinerFan
    Joined: Jan 2012
    Posts: 29
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    Location: Melissa, Texas

    OceanLinerFan Junior Member

    Hello everyone,

    It's been a while since I've been on these forums, and since then I just completed my first year of Naval Architecture courses at the Marine Institute in St. John's, Newfoundland, Canada. I'm going into my second year of studies in September 2017.

    Anyways, I have continued to look into "efficient" passenger liner concepts from a speed/powering perspective. One idea that has intrigued me is creating a passenger liner concept that would be relatively restricted in dimensions (Panamax specifically) but be able to move at the same speed as the legendary SS United States (38 kts). Her general "look" is based on the PXE ocean liner design from the Maritime Commission created in 1945.

    Figure 1: PXE ocean liner outboard/inboard profile from the U.S. Maritime Commission, 1945

    Basic stats of the PXE (pulled from Damned by Destiny book):
    -Waterline Length: 895 ft
    -Beam: 85 ft
    -Depth to strength deck: 71 ft
    -Longitudional coefficient (Cp): 0.57
    -Powerplant: geared steam turbines
    -Designed displacement: 37,500 tons
    Fuel oil capacity: 9,500 tons
    Fresh water: 800 tons
    Swimming pools: 200 tons
    Passengers, luggage, crew, provisions: 1000 tons
    Dry cargo: 1,350 tons
    Reefer cargo: 150 tons
    -Total deadweight: 13,000 tons
    -Designed speed: 29 kts
    -Designed SHP: 100,000
    -Number of screws: 2
    -Designed steaming radius: 12,500 nautical miles
    -Passengers/Crew: 1000/496
    -Bale capacity: 150,000 ft^3
    -Reefer capacity: 15,000 ft^3

    Machinery wise, she would have been novel in that she would have been a twin screw vessel with only 4 boilers (2 boilers per shaft) meaning a loading of 50,000 SHP per shaftline. These would have been the largest marine boilers ever made (no specifications on the steam conditions of these boilers, but its very likely that they would have been of the 850 psi/900 F type as in an earlier, smaller passenger liner concept design for the South American service to Rio).
    Now, with my "base ship" out of the way, these are the preliminary specs that I have outlined for a faster version of this type of ship, with some of my own design "tweaks" to suit my own design style.

    LOA: 962 ft
    LWL: 920 ft
    Beam (overall/waterline): 101 ft
    Draft (normal load): 30.5 ft
    Depth to Main Deck: 73 ft

    Service speed: 34 kts
    Maximum speed: 38 kts

    1. Form Coefficients/Displacement --
    Block Coefficient: 0.523
    Displacement: 42,350 long tons
    Wetted Surface Area: 105,930 ft^2 (estimate, includes +10% for appendages)

    2. Resistance and Powering Estimate (for maximum speed of 38 kts):
    Froude Number: 0.37267
    Reynold's Number: 5.105 x 10^9
    Frictional Drag Coefficient: 12.918 x 10^-4
    Residual Drag Coefficient: 21.295 x 10^-4
    Delta-Cf: 1.0 x 10^-4
    Total Resistance: 1,528,807 pounds (lbf)

    Quasi-Propulsive Coefficient (estimate): 65.03% (based upon some empirical formulae I found)
    Effective HP (EHP): 178,510
    Shaft HP (SHP): 274,502 [nominal 280,000 SHP plant required]

    3. Ship Centers (estimate from formulae I found):
    Cwp = 0.70 (taken as normal) --> 65,044 ft^2 waterplane area
    Waterplane Moment of Inertia = 38,704,974 ft^4

    BM = 26.11 ft
    + KB = 17.82 ft
    KM = 43.93 ft
    - KG = 38.32 ft <--- based on roughly 52.5% of ship's hull depth, liberal estimate
    G.M. = 5.61 ft (1.71 m)

    This is all I have derived from my calculations so far. It's possible that I will continue to develop this (and my MS CANADA liner) as I continue my Naval Architecture studies at the Marine Institute this year and next. It's a concept that I think might be interesting to pursue sometime after I graduate. I would love any feedback on what I have laid down so far.
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