Page 155 - Practical Ship Design

122 Chapter 4

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V 1 W Z 1 AA
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Resistance Powering
7 Ct inclusive
8 service speed Vk Pe = 0.0697 . Ct . S . V3(kW)
9 Froude Fn = 0.1 64 Vk/& prop diameter
10 Rn = 2.636 x 1 O6 Fn . L’ service RPM
11 QPC = 0.84 - (Nd)/lOOOO
12 Ps = Pe/QPC (kW)
13 trial margin
14 Cb Ps (trial) (kW)
15 A service margin
16 C Ps (service) (kW)
17 S = C/AL derating
18 ’s’ = 1.01 66 S/A‘” MCR (kW)
19 Lb (basis or model)
20 Bb C app as Yo Ct
21 Tb rudder 1.5%
22 Rnb twin rudders 2.8%
23 (1 + K) shaft bkts and shafts 6%
24 Ctb stabiliser fins 2.8%
25 Cfd = 0.075/,/- bilge keels 1.4%
26 Cfd (use Rnb) powering assumes SW (r = 1.025)
27 Ctd = Ctb + (1 + K) (Cfd - Cfb) fb - fall back value
28 6’ = B(LWL) machinery type chosen
29 T’ = T(Lb/L)
30 Mumford corrections B & T
31 Ct corrected L,B,T approx capacity check
32 AC (fb = 0.10 x 1@)
33 c aPP depth D
34 C air sheer camber
35 Ct inclusive D’ corr S & C
36 gross vol L . B . D’ . Cbd
37 deductions
38 additions above upper deck
39 gross cargo cubic
40 structure deduction
41
42 cargo cubic
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Fig. 4.19(d). Spreadsheet for merchant ship design (continued). Powering and approximate capacity
calculations.