A little progress...

Afternoon!

Not a lot done this week. I've recalculated the size of the keel bulb and that is half the width I thought it needed to which equals a cash and weight saving.

I had a play around with it in Pro-E and it is complete (on one side) bar creating the indent for the keel itself. I need to go through the manuals at work to find out how to move one of the reference lines to complete the keel indent.

Hopefully I'll get more done next week, but I doubt it. :)

Have a good week!

Further progress...

Afternoon!

Okay, so it’s been 2 months since I last posted. I was having such a good run, but life got in the way and the mother-in-law (plus others) got in the way of this weekend, I'm just lucky it's a bank holiday Monday here today.

So this weekend, I have done quite a bit of the small stuff. I started by adapting the connection between the keel and the mast to one solid component to reduce weight and add strength.

Before with dual plates:

After with it connected to the keel plate, and a bit of rework done on the keel plate.

Mast support pin included. It’s a bit long right now, but I don’t know how much is required to weld it in place. This is there to add strength to the mast and (hopefully) prevent it being ripped off the boat in high winds.

Holes have been put in the deck for the mast support. This doesn’t look very clean in this photo, but as there will be some play in the position overall and the holes in the rubber seals are smaller than the holes in the deck/supports so it hasn’t lined up properly, which means I’m not worried if it’s 0.5mm out.

I have adjusted the plate that supports the mast internally in the boat to take the M8 lock nuts. This cut out is to hold the position of them so that they can be spot welded into place and the boat doesn’t have to be opened when the mast is attached.

Below is the first version of one half of the keel bulb.

This is how it’ll attach to the keel with bolts obviously. On a second look, I was thinking how big it appears. I did a quick check on it and I need 579 cm^3 of lead to make the whole keel bulb. This one is 837 cm^3 as it is. I will need to revisit this next weekend (or whenever I can work) and redo my calculation on it’s size.

Anyway, to finish off, this is how my boat looks now. Not the best picture in the world, but you get the idea.

Next Steps

Rework bulb size calc and create bulb.

Rear bulb on boat

Sail boom supports

Sail top support

Hole in rib section for keel plate.

Inserts on backbone to support keel plate.

So much work still to go. Getting there slowly through via a lot of procrastination... :)

Mast sizing finalised and added to the model

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!