Hello all!
3 weeks in a row. Now
this is what it’s about!
I will admit that I
didn’t get a huge amount done this weekend. I went out Saturday afternoon for a
long run which wiped me out a bit. Now, as I sit here on Sunday, I have a massive
headache, so it’s time to quit.
What I did do this
weekend is to sort the mast out. From the calculation I did 2 weeks ago, I
revisited it and added more selections to find out exactly when the deflection
starts to “bottom out” on the exponential curve.
Carbon
Fibre Tube Inner Diameter
|
Carbon
Fibre Tube Thickness
|
Force
at 850mm
|
Deflection
(Bend distance)
|
Bending
Stress
|
||||
mm
|
Inches
|
mm
|
Inches
|
N
|
Pounds
|
Inches
|
mm
|
psi
|
14
|
0.55
|
1.35
|
0.05
|
68.24
|
15.34
|
2.745
|
69.723
|
54622
|
18
|
0.71
|
1.4
|
0.06
|
68.24
|
15.34
|
1.087
|
27.6098
|
27922
|
19
|
0.75
|
1.4
|
0.06
|
68.24
|
15.34
|
0.9097
|
23.10638
|
24680
|
22.2
|
0.87
|
1.4
|
0.06
|
68.24
|
15.34
|
0.563
|
14.3002
|
17734
|
26.5
|
1.04
|
1.4
|
0.06
|
68.24
|
15.34
|
0.319
|
8.1026
|
11991
|
28.5
|
1.12
|
1.4
|
0.06
|
68.24
|
15.34
|
0.252
|
6.4008
|
10210
|
32
|
1.26
|
1.4
|
0.06
|
68.24
|
15.34
|
0.174
|
4.4196
|
7922
|
35
|
1.38
|
1.4
|
0.06
|
68.24
|
15.34
|
0.131
|
3.3274
|
6522
|
38.1
|
1.50
|
1.4
|
0.06
|
68.24
|
15.34
|
0.1006
|
2.55524
|
5462
|
42
|
1.65
|
1.4
|
0.06
|
68.24
|
15.34
|
0.075
|
1.905
|
4465
|
46
|
1.81
|
1.4
|
0.06
|
68.24
|
15.34
|
0.056
|
1.4224
|
3674
|
47.5
|
1.87
|
1.4
|
0.06
|
68.24
|
15.34
|
0.051
|
1.2954
|
3431
|
50.8
|
2.00
|
1.6
|
0.06
|
68.24
|
15.34
|
0.04
|
1.016
|
2981
|
60.3
|
2.37
|
1.6
|
0.06
|
68.24
|
15.34
|
0.024
|
0.6096
|
2093
|
So from the graph I
produced, the reduction in the deflection significantly decreases as we
approach the 40mm+ region. So, I made a design decision to go with a mast
diameter of 46mm. This 46mm is an inner diameter, the outer diameter of the
mast will now be 48.8mm. By sheer luck, this should make obtaining the right
size materials to produce it easier.
So I’ve updated all of
the parts associated with the mast to accommodate the new size and it now looks
like this:
I have also created and
inserted the rubber seals around the mast, both inside and outside the vessel:
I hope to have a better
go at it next weekend. But I’m giving up for today and I’m off to find
ibuprofen.
Next Steps
- Pin through mast to hold in place.
- Holes in deck for mast
- Rear bulb on boat
- Sail boom supports
- Sail top support
- Keel bulb size and shape.
Until next weekend!
Enjoy your week!
