The $1000 Sailboat

[Tailmaker]

As you may see from previous project posts, I am not so much in the decorative and artsy stuff but rather prefer unique utilitarian, technical and practical CNC projects. So here is my latest effort if you want to indulge in a few posts with pictures and the explanation.

Background: I used to have a 14ft catamaran some 30 years ago but sold it due to family, job, moving, etc. Now retired, I want to have another sailboat without spending a lot of money so I set my goal of building a small catamaran based on an inflatable cataraft for less than $1000. Spoiler alert: I ended up spending about $1400 but at least I got it finished and tested before winter

Here is the concept as done on 3D CAD. Main purchased components: The raft, a lateen style Sunfish dinghy sail and some aluminum tubing.

I made a transom and rudder brackets from bamboo and BB plywood. This was simple 2D profiles with some chamfering paths.

The rudder blades are Baltic birch plywood, cut out 2-sided with profile tool paths and coated with a few layers of epoxy.

To be continued...

[Tailmaker]

Continued.
The rudders are self releasing due to the need to beach the boat:

Normal operation:

Half raised for shallow water:

Fully raised to take in and out:

To be continued....

[Tailmaker]

Continued...

I did not want to go for typical daggerboards since awkward to attach to an inflatable so I decided to go for mini-keels to provide the required lateral drag.

The keels were cut like the rudders with 2-sided molding tool paths for better hydrodynamic shape:

The keel base was a full 2-sided 3-d cut from 1.5" plywood to conform with the inflatable hulls:

Assembled with screws and construction adhesive. The inside of the base has a number of flutes projected onto the 3d-shape (to lock with ridges on the inflatable hull). The skid rails should help protect the plywood when beaching:

Attached to the hulls with ratchet straps:

To be continued...

[Tailmaker]

Continued...

Ready to go, some features of the trailer were also made on the CNC machine:

On the water:

Finally sailing. Well, was not much wind that first day.

Happy owner :

It was 80 degrees and 4 weeks after the first snow storm in Northern Colorado. Weird weather but at least the wind direction blew all the wildfire smoke away.

[highpockets]

Awesome project!!!

[garylmast]

John took the words right out of my mouth. "Awesome project".

Gary

[RebeccaJ]

Wow this is a fantastic project! You really pushed the boat out with this one Great job and very inspiring! Now for all the adventures hey! Well done

[Bobtail Farm]

+1

[scottp55]

Aah...It's finished!!
What a Project G. !!
Must have been a few modelling challenges/ a few fixturing challenges as well!
Love your twin keel shapes:)

What was most challenging for fixtures on your machine?

GLAD to see the customer was happy!!
He deserves a pat on the shoulder!
Wonderful work, Well done!
scott

[Tailmaker]

Thanks All for the nice words. It was a fun project but I should have started it in Spring. I barely made it to the end of the season. Oh well.

Aah...It's finished!!
What a Project G. !!
Must have been a few modelling challenges/ a few fixturing challenges as well!
Love your twin keel shapes:)

I started the design and ordered the inflatable hulls sometimes early August. The 3d design was work in progress until now, I am on version 24 of the 3d design. If somebody is interested, a downloadable version in .obj and .wrl is here: https://www.dropbox.com/s/3pl8spndj4b7k ... 4.zip?dl=0
You can even load it in Aspire but also possible to view with Windows on-board tools.

What was most challenging for fixtures on your machine?

Biggest problem was that the parts were way too big for my machine. I could have dropped in my machine extension table gadget (https://youtu.be/fClejhSXwoM) but found it simpler for this one-off project to just tile the tool paths. I did not use dowels, just shifted the blanks against a fence by tape measure and eyeball and clamped them down with spacers. Not super accurate and you can see some tile transitions in the plywood patterns. But I am a follower of the good-enough-for-the-purpose doctrine and the random orbital sander can smooth out a lot.