Rudder laminate design
 Share
The version of the browser you are using is no longer supported. Please upgrade to a supported browser.Dismiss

 
$
%
123
 
 
 
 
 
 
 
 
 
 
 
 
 
 
ABCDEFGHIJKLMNOPQRST
1
2
adapted from the Antrim/Pineapple sails method available at: http://www.well.com/user/pk/PCrudder.html (Except rudder force -A6thru A12- is based on Dave Gerr's "Elements of Boat Strength".)
3
Fill in the yellow cells!
4
6Design speed, the fastest your boat will be moving when you deflect the rudder "hard over", in knots
5
4Underwater surface area of the rudder, in s.f.
6
494 = Total pressure (force) on rudder, pounds
7
8
3.5Horiz. distance gudgeon CL to center of pressure (CP) of rudder, inches. (assume CP @ 35% aft of LE)
9
18Vert. distance from lower gudgeon to centroid/center of pressure of rudder, inches.
10
8,884bending moment, in.-lbs.
11
1,727twisting moment, in.-lbs.
12
9,050combined moment, in.-lbs.
13
14
3Safety factor, between 2 and 4 suggested
15
100000Design stress of laminate, from 10,000 for fiberglass cloth, to 100,000 for carbon with uni fibers. psi
16
0.271Required Section Modulus, in^30.271
17
Marko:
18
10Width of blade, inches.10
19
1.2Design thickness of blade, inches1.50
20
1.126Core thickness, inches1.438
21
0.037Skin thickness required, inches (at lower gudgeon/point of max bending)0.029
22
21Total fiber ounces per yard to achieve skin thickness16548g/sqm
23
24
25
Gudgeon load calcs
26
10Distance between gudgeons,inches10
27
888Force on upper gudgeon, pounds4kN
28
1,382Force on lower gudgeon, pounds6kN
29
0.19618-8 hardened stainless pin diameter, inches (loaded in single shear)4.969mm
30
31
Note: grounding loads or impact loads are not considered, nor is "hoop" or compression
32
strength to resist pintle strap loading. These calculations are not my own, although they
33
appear to match real world experience. USE AT YOUR OWN RISK!!!
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
Loading...
 
 
 
Sheet1
Copy of Sheet1
 
 
Main menu