New Naca 0014 Foil Rudder for our Com Pac 19

[DOUG142]

Well, I went ahead and did it now!  Building yet another NACA 0014 rudder.
It is shaping up nicely.   See progress pictures on our photobucket  folder by clicking on the WORLD icon on left side.

Foam is sooooooooooooo much easier that the layered wood one.  It will be glassed over and painted.  Color?

Doug142

[HideAway]

I asked our resident legend, Bruce Bingham - he's the guy who designed the hull of the Eclipse and has a long history with Compac and many others.  I asked him about the NACA foil rudder for HideAway.  He is in complete agreement with the need to make the change and the design. the 12 or the 14 is fine for our boats no wider.  He's also the guy who convinced me to become loose footed with our main sail and he was dead on with that -- the combination will be wonderful  Matt

[DOUG142]

Hide,
Do you need a template for either the 12 or 14 foil?  I have sent several to other fellow com-pac sailors.  Email me your address and I will send out a copy of each to you.

Doug
1983 CP-19 s/v Sweet Dreams

[CaptK]

Doug -

Your work is eerily similar to what I did with my CP23 rudder back in '02-03. My old website had big pics that are no longer accessible, but you can still see the thumbnails here. I was making mine as a 2-piece, with the intention to be able to bond the two halves to the rudder plate itself *after* they were glassed. This was for two reasons: as a way to avoid water ingress into the foam, and to make it easy for any CP owner to add them to their boat. A buddy who I used to work with in the surfboard industry was going to pull a mold off of my design, and we were thinking we would be able to "semi-mass produce" a set of aftermarket foils for CP'ers, since at the time there was nobody making them other than just a few individual owners.

Then, about the time I was finishing up the last fine work on the foils, I began collaborating* with Joel at IdaSailor in order for him to start production on the HDPE foils he still produces for Com-Pacs. That material was a better solution, was my thinking, as it was impervious to water, and largely the same to rocks or ramps. Also, I didn't really want to get into yet another business, lol. Joel made the first prototype from my dimensions, sent it to me, and after a bit of testing and refinement and another try or two until it was perfect, it became a standard item offered thru his company.

I useda NACA-12 foil as it seemed to be the closest to what was needed for the speed of CP's. The first time I put a foil on the rudder I was *amazed* at what a huge difference in immediately made in how the boat handled.



-------

Disclaimer: I got to keep the final prototype for my boat. Other than that, I don't get any reimbursement or kickbacks.

[DOUG142]

CaptnK,
Thanks,  my first one was layered luan ply.  A LOT of work!!!  It is still in use today with our com-pac 16's new owners. 
doug

[Bob Condon]

Captain,

Is HDPE another word for Azek products? -or- is there a product name.

I made a new motor mount for my CP19. I have an NC spindle bed
which made very short work to cut out and flue together and now
putting a weather resistent finish on it...   Does anyone else need on... I can make them
inexpensively...

I want to build a Nacra 014 foil this winter and was going to use a foam and
glass but you are saying that HDPE is a better base product before the glass. This would
be an easy fall project.

Thanks

Bob Condon

[CaptK]

Hi Bob -

For folks who may not know: "Azek" is a product name for sheet foam PVC (Poly Vinyl Chloride). It is not a light product like insulation or deck-core foams; it is lighter than a plain sheet HDPE of a similar dimension, and nowhere near as heavy as HMWPE (High-Molecular Weight Polyethylene), which is what "StarBoard" is.

I made a large rooftop garden out of Azek for my sister a few years back. Interesting stuff. Turned some scraps into my 'screen door' companionway boards.

Based on what I've seen, I believe Joel is using plain sheet HDPE material on his foils. Think "white plastic cutting board material", it is pretty much that. Tough stuff! He makes the foiled part of the blade of that material, and mounts it onto a stainless steel 'spine' for strength. The HDPE material does not have a lot of resistance to bending, so I think the spine is essential.

You could do the same with Azek, and Azek would be easier to work, but it will have a rougher surface (more porous) when finished, and not be as resistant to getting dings. Maybe coating it with epoxy resin then paint after shaping, to smooth it out. Simple to test that before going all out with the project.

HTH!

[Bob23]

   In a departure from the norm, which seems to be normal for me, I built my foiled rudder using the original plate rudder as a base. 4 foiled frames of hardwood were bolted and epoxied to each side of the blade, the spaces between were filled with foam and sanded to the foil shape of the frames and the whole shebang was skinned with 3mm Okoume plywood from CLC.
   The result was a wood foiled rudder blade that has worked great and is serving as a prototype and test rudder. I designed a downhaul to keep the floatable blade from floating up. The wood matches the teak on Koinonia almost perfectly.
   I documented some of the building process on "The Continuing Adventures of Koinonia" in the 23 section. It looks great hanging off the transom of the ship. If I ever learn to post photos (please don't laugh) you all will see what I mean.
   The entire project took a long time to complete due to my advanced degree in procrastinationogics and my tendecy to be a prefectioninst. Thanks are due to Doug 142 who sent me the NACA 0014 foil template. Inspiration was from others here at the site who were building foiled rudders last winter. I just took a different path than the others...the road less travelled.
    Bob23

[Bob Condon]

Thanks Bob23 and CaptainK

Thanks especially for the descriptive difference

I now have my plate at home so I can have a Stainless Steel spine welded up.

I think I will look for HDPE locally but I know I can get full sheets of 3/4 Asek for $130
and I understand I can get HDPE 12x48 is around 80....

I was thinking of using epoxy and fiberglass to improve the ding-resistence.

I also need to make a new tiller... Mine rotted out between the two pieces of aluminum
and came apart when we were coming in to pull the boat for the season... quite the shock...

Again, thanks

Bob

[rwdsr]

Is that AZEK stuff expensive?  Was thinking I might like to make the hatch out of that.  The one that came with the boat was really rotten and just fell apart when I tried to open it when I first got the boat. (Can't believe it's coming up on a year already.) So I used the old wood for a pattern and cut a new hatch out of plywood, then 6-8 coats of spar varathane and later on I put the window and screen in it.  Also where do you get that?

[Bob Condon]

home depot has a 1x8 board 8' long for around $25. With a router, it cuts just like wood. The N/C machine
cuts it very clean. A friend was making a half circle to make a startburst with the clapboards...

I am contemplating using it for making latice frames for under the porch... It will last forever with the new
Vinyl lattice.

The companionway hatch would be an excellent project

[Potcake boy]

Gentlemen - what is an NC machine?  Would it add much to the clutter filling my garage?

Ron

[Bob Condon]

N/c Machine is a Numerically Controlled computer driven router/spindle.

SO I can mount a piece of wood in the bed of the machine (which is 5 feet x 9 feet)  BIG garage clutter
and with a computer I can design a 3 dimensional picture (a  sign, a wooden picture of the Last Supper)
and can drive any number of carbide router/machining bits through wood, plastic, light metal etc to make
objects...

so for the rudder, I would create a file which contains all the x,y,z points on a rudder and ever 1/8", run a cutter
through those points and make a smooth shape of a rudder, which I would sand and finish.

Making a new motor mount block for my Cp19 took 5 minutes to design, 5 minutes to write the files and bring to the machine,
and about 7 minutes to cut after I mounted the block on the table.

The machine I own is on website: http://www.shopbottools.com/mProducts/prSalpha.htm

I make a lot of signage, put playing with things like custom rudders, etc...

Bob Condon

[DOUG142]

Sorry, don't have an extra $20,000 laying around for one of those!  I fiberglass'd my hand shaped and sanded foil this morning.  Looking good at my photobucket files at left side of this post ...click on the World icon.
Save $$$
Doug

[Salty19]

Pic of the IDA HPDE NACA0012 rudder with stainless "spine" Captl was talking about...



And heck one from the 16 with attached mast crutch for good measure
Very nice units. The auto kickup/down feature works well when in shallow water.