Rudder blade all laminated

The plans call for an extra layer of fabric around the top of the rudder blade and down the leading edge.  I decided to apply this reinforcement before the final complete wrap.   

Then the wrap of carbon fabric went on in one piece.  I also had some light weight fiberglass cloth (It seemed too light to be 6oz, it is probably 3.7oz) and applied this as the final layer for abrasion resistance.  

It would have been a good thing to use peel ply on this final wrap.  Just using plastic results in excess resin sitting on top of the fabric here and there.  But the final result is not bad for a hand layup.

I'm fairly happy with the final shape.  The overall thickness might be a mm thicker than the plans template,  and the trailing edge might be ~3.5mm thick.

The blade weight is 4.78 lbs and with the laminations complete  I can now move onto the rudder sleeve.  In this part the blade will actually be used as a mold.

 

Sheathing the rudder blade

January 2009 is just moving on at lightspeed so I thought I should post some small progress made on the rudder blade.

The Christmas break gave me the opportunity to stand back a bit, review other builders work, and it did not take me long to see that I made a mistake in the rudder blade uni-directional re-inforcements.  You never apply uni-directional directly onto the foam substrate directly.  It is always applied on top of some bi-directional re-inforcement.  In any event I somehow went ahead and laid down the carbon uni directly on top of the foam and the wrapped high density core.  Not as per the plans direction.  The plans call for the uni-directional to be sandwiched between the two layers of sheathing.  This was a strange error for me considering that I laid up the daggerboard correctly last winter.

I considered routing out all that unidirectional, but decided to leave that half of the rudder blade as is and make the other side correctly.  If it breaks at some point - my bad.   It will be my rudder blade half made right.

Here is a picture of the the complete rudder blade wrapped and the 6 oz carbon fiber (2x2 tweed weave) wetted out with the uni-directional apllied correctly on top of the cloth (at least on the one side).  

I'm in the process of smoothing out and rebuilding the appropriate shape over the uni-directional fiber before I apply the final sheathing layer.  The shape and overall thickness seems OK at this point.

Uni-directional carbon fiber in the rudder blade (updated)

There are a number of steps involved in getting the basic foam core re-inforced properly.  After the wrapped high density core is inserted,  some unidirectional carbon fiber tape has to be laid down on top of it.

Here are the pieces of tape cut to length and ready for application.  I used a 9 oz. weight carbon fiber  tape.  I can never get the tape trimmed as perfect as the plans show it.   You can also see the rebate around the high density core.  I tried to tailor the depth of the rebate down the length of the blade but I am sure some fairing putty will be required to get the profile shape back.  I'm always slightly phobic about making the rebate deep enough (is the high density core too thick?, is it mounted properly?), but I just stick to the dimensions indicated in the plans.

First I filled up the gaps around the rounded corners of the high density core with some high density putty.

And while still wet applied the layers of carbon tape.  The epoxy saturated  carbon uni-directional material really needs to be compressed and using a plastic sheet to squeeze out the excess resin really does minimize the overall thickness, which I think is what you really want.  

Everthing looks good and when it's cured I will apply the fairing putty to the trailing edge of the blade and recover the profile shape over all this carbon fiber.  Then turn the blade over and do the other side.

Updated December 23rd

Work has slowed a bit with Christmas and other projects but I have made a bit of progress in finishing off the one side of the rudder blade.

The above picture shows the trailing edge cut away to the centre and is ready for the lightweight putty fill.  The original layer of 6 oz fiberglass cloth really helps here to cut away one side of the blade at a time.

Here is the blade (port side) with the putty applied and sanded down close to a point that is almost ready for carbon fiber cloth sheathing.  I will now turn the blade over and finish the other side but  I have run low on carbon fiber and will have to visit Noah's or Canada Composites soon. ( A trip to the other side of Toronto).   I want to make sure I have enough material to finish the blade and rudder case.  This will be my last post of the year so merry Christmas and a happy new year to all.  2009 should be interesting. 

Inserting the final high density core into the rudder blade

The final high density insert has to be wrapped in carbon fiber (F-22R option) and helps to create the longitudinal rigidity required in a modern lightweight foam rudder.  The high density foam is tailored in thickness so that further uni-directional carbon can be added on top of each side without adding thickness to the rudder blade.

I wrapped the upper and lower halves seperately so that it could be held for wrapping.  You can see the plastic stretch wrap which really helps to hold the carbon cloth in place.  It also allows all the excess resin to be squeezed out to either end.  

For some reason I decided to shape the foam before glueing in this core.  It probably would have been easier to insert the tailored wrapped core into the original rectangular block of foam, and then do the shaping.  Inserting the core after shaping required the use of some simple jigs, spacers and clamps to make sure there was no twisting or mis-alignment in the blade while the epoxy glue was hardening.

The offcuts from the original blade block of foam were put to good use.  The operation was successful and I am now putting in the rebates for the uni-directional re-inforcements.

Rudder blade foam shaping

Fellow builder Menno had a idea that he shared on the builders group.  He wrote

"My idea is to draw lines on the blank lengthwise, combining all points where the rudder/centerboard has the same thickness. Then use a router to make grooves with the correct depth and use those grooves as a guide..."

Something about this idea stuck with me and the thought of again artistically shaping the blade through the use of the templates seemed like a lot of work.  I know,  I shaped the daggerboard that way last winter.  So I decided to give the router approach a try.

Above is the block of foam with the high density inserts in place.  The block is thicker than required but I wanted to glue the foam  so that the centre had a glue joint.  I also applied a light fiberglass cloth in this centre joint (as I did on the daggerboard)  so that this thin blade might hold together a bit better.  Using the full size plan I transferred the lines.  All the arrows are to remind me to keep the cutter to the outside. 

I've used this mini-router before to create rebates where needed.  This time it is being put to very good use.
Removing the extra block thickness.

I used the oribital sander to get the shape close and then finally some hand sanding. 

And viola, here it is,  close enough to start work on getting the high density foam core inserted down the middle.   I wish I had made the daggerboard this way, this approach is much easier for me.  

 

Two more F-22's launched

Ian Farrier has posted pictures of two more F-22's launched in Australia and the Philippines.  The pictures can be seen here.

I suspect we will see more Farrier trimarans coming out of Melvest Marine.  If you check the link to their web site you can download a pricing spreadsheet for your very own F-22, if you want. Anyway,  I am still waiting for good pictures of an F-22 sailing hard with the screacher flying from the bow pole.

Work on the rudder is going well and I should have an update very soon. 

Bobstay bow eye

My family finds the name of this part interesting.  Say it three times really fast.  

Kidding aside,  I take the function of this part very seriously.  This bow eye has to take a substantial part of the load that will be created when the screacher is flying from the bow pole.   The bobstay holds down the bow pole and is connected to this eye which is mounted fairly low in the bow of the boat.   Knowing that I will probably like to drive the boat pretty hard I want to do a good job on the part.  It's another one of those parts that reduce the amount of metal in the boat and requires the use of carbon fiber.

I was able to make the part entirely from cut-off and left over material.  Above is the initial foam core that I artistically created from one piece of foam cut out from the daggerboard core.

The actual bow eye is made from a simple mold, tape and two pieces of foam and some high density putty (Cabosil and epoxy resin).  

I found that cutting and applying  the narrow strips of carbon interesting.  The unidirectional is made by knitting together bundles of carbon fiber strands  in parallel.  It was impossible to keep the knitting together with a cut of the stitching every 5 bundles, so the wrapping consisted of gathering up 5 individual bundles and wrapping them around the bow eye.  The two plastic plates really helped to keep the bundles in place.  

Final covering with the s-glass cloth was also quite challenging.  I have to admit I finally resorted to using a stretch  plastic food wrap to keep the cloth down.  I saw this hint from a post to the buildersgroup by Andrew Cuthbert.

I used a small piece of G10 tube that was cut off in making the rudder mount to help make a solid bow eye opening.  I plan to lash the bobstay synthetic rope (no shackle) so I also tried to  'bell mouth' the opening as I do not think that synthetics like a tight radius.

Don't think I can put off working on the rudder any longer.