Water Resistant Finish

[Burkhardt]

Thanks for the detailed instructions, very helpful! I still have a few Bondo spreaders but with this super low viscosity resin I guess a brush is the easier way to go.

I dug out my old project material and I found a roll of Carbon/Kevlar twill and a roll of glass fiber twill fabric. My wife tells me that I am a hoarder, not sure why...
While the black and yellow Carbon/Kevlar really looks cool, I will go with the glass fiber since it is easier to check the wetting and bubbles. Also, sanding Kevlar composite is near impossible without a lot of fuzz.

Last time I used that stuff was for a similar catamaran some 30 years ago, although back then with wooden hulls. So I after 30 years I am bit out of practice with the lamination business...

Anyway, I put a first thin sealing coat on the rudder blades today as recommended and will add a layer of the glass fiber tomorrow. There were bunch of bubbles but the torch did not work as intended. While waving the flame burst the big bubbles, the heat apparently made the wood expel more air and I ended up with hundreds of tiny bubbles. A few strokes with the brush removed most of that and I will sand the surface smooth before proceeding.

[Brian Harnett]

Viscosity really has nothing to do with, it I use west system it is pretty thin the Bondo spreader squeegees out excess, too much epoxy actually weakens the lamination and adds weight. probably not an issue in your case. Its spreads way more effectively than a brush.

[Burkhardt]

Oh well I changed my mind again...after seeing the nice contiguous coat of the epoxy (I used a thin and a thick layer of the System Three Clear Coat) I decided to forego the glass fiber layup. Given the short immersion I hope this will be good enough.

Here some progress pics:

Rudder Blades after epoxy coating
DSC01939-001.jpg

Rudder brackets/hinges and transom installed
DSC01944-001.jpg

[coryatjohn]

Looks nice! You can always sand it and add a few layers of glass at a later time if you feel the need.

[scottp55]

Looking good G. !

Are you adding something at the interface of wood/inflatable to reduce chafing?

scott

[Burkhardt]

Looking good G. !

Are you adding something at the interface of wood/inflatable to reduce chafing?

scott

Not sure yet. I will watch if there is surface abrasion. If so I may glue a wear strip onto the inflatable hull or add some cushioning in between.

[Burkhardt]

More progress. We had a bout of frost and snow last week here in Ft. Collins but this weekend it was nice, sunny and 80+ degrees again. So I hope I will still have a chance to try the boat this year

I installed the rudder blades, they are made to allow for beaching without damage:

Operating position:
IMG_2078.JPG

Half-raised position, should be still maneuvrable:
IMG_2080.JPG

Fully raised for taking in/out:
IMG_2081.JPG

[Burkhardt]

I decided to eliminate the daggerboards. Just too awkward with an inflatable catamaran. Or maybe I did not have a good solution for it.

Instead I made some mini-keels and the appropriate base boards to strap to the hulls. Maybe not as efficient but Hobie Cats have not had daggerboards for a long time.

The keels are machined double sided, using the Vectric molding toolpath.
The base boards are fully 3D machined from 1.5" BB plywood. Even with a 1/2" ballnose it took a couple of hours...

Since the 6' length exceeded my machine limits, I used 3 tiles. Worked kind of O.K. although it is difficult to align the tiles better than maybe 20/1000" (I could not use dowels). But that is what the sander is good for.

Keel base boards:
IMG_2129.JPG

Mini-Keels:
IMG_2132.JPG

Tomorrow I will glue and screw the keels to the baseboard.

Another little gadget: Since the inflatable does not allow for a real traveler for the main sheet with a rail, I designed a kind of "flying traveler", using a single block and two cam cleats. I am curious how that will work:
IMG_2130.JPG

[coryatjohn]

Looks great! Hope it works.