Center board trunks

[Greg Luckett]

The Spindrift plan set calls for two coats of epoxy on the inside of the C/B trunk prior to assembly.  I am wondering if it should have a layer of fiberglass cloth as well?

Opinions/discussion please, and thank you.

[brucee]

Hi Greg,

Given that the inside of the daggerboard trunk is awkward to maintain once assembled and installed, and has a board sliding up and down it, I intend to use some fibreglas cloth inside the trunk on my Spindrift before assembling.  I'll probably use 4 or 6 oz cloth.  The cloth also guarantees a uniform thickness of resin on the surfaces.  See the attached table for additional weight added, which I figure will be maybe two or three ounces for the daggerboard trunk.

http://www.boatdesign.net/forums/attachment.php?attachmentid=3985&d=1126213824

Now if I can just slow down the weekend summer fun and busy days at work, I'll be able to make some progress on my Spindrift.

cheers,

Bruce

[Gordy Hill]

I coated the centerboard and rudder blade with epoxy with graphite. After sanding it down to 600 grit they looked like expensive carbon fiber pieces. I'd consider using graphite-epoxy on the inside of the centerboard trunk as well.

[Charlie Jones]

Greg- a layer of cloth won't hurt at all.As I also posted on another thread somewhere, I also coat the inside of the trunk with an epoxy/graphite mix ( several coats) to help make things slide a bit easier.

[Greg Luckett]

Thanks Charlie.  That has helped me make up my mind, as did the advice from Gordy and brucee.  I have had several boats with CB trunks and those were always a maintenance headache to do anything inside the trunk.  I have ordered some carbon from Chuck this evening since no one around here seems to stock it.  I have not assembled the trunk yet so the timing is good, and the CB is not yet built either.  I can easily make whatever adjustments are needed at this point.

We rolled the Spindrift over to finish the hull and get the keel installed prior to cutting out the CB trunk hole.  This will take me several days to reach that point.  I only work on the boat a few hours a day.

Thanks again you all!

[Maria CS20 104]

I have my centerboard template piece cut and ready for the plane.  Once cut down and sanded to shape do ya'll recommend fiberglassing the blade (4 oz?).  If so I think I should plane to 1" and build up to 1 1/8th with the glass and epoxy.  Comments.  The blade is laminated Walnut and Hickory strips and resulting board is 1 5/8ths thick before planning, shaping and sanding.  I was thinking (foolish of course) I'd add the handle after planning and then sand the whole lot as I shape it out to final dimension.  Ideas? :-\

Jim

[Greg Luckett]

I have been wondering the same thing.

How was the hickory for machining and gluing?  Two relatively hard woods.  I am thinking of using Sassafras and Black Walnut for my blade.

[Gordy Hill]

I can't see any reason for using up nice looking wood for a centerboard. It's really hard to beat fir.

It probably wouldn't make a difference, but it seems your board would be more stable if you stick to just one wood. However, I don't think you have to worry too much about electrolisis between dissimilar woods.......

[Greg Luckett]

LOL Gordy...ie. electrolisis.

I already own plenty of the Sassafras, walnut, oaks, maples, and basswood.  I do not have a good source of fir around here and would have to hunt for it and buy it too.  The Sassy will do nicely for spars too....I think.

[Maria CS20 104]

Hey Greg, I found the planning of the raw boards easy enough to take down for hickory, Sasafras will plane cleaner and look as good, not as ivory as hickory though.  Walnut planes better than most poods I've dealth with especially if it is 1st or 2nd cut having no knots or fragmented grain patterns.  I did alternate the grain and I put buscuits on a 3-2 pattern to stagger and add strength to the joins.  I got the wood for free and the hickory was a bit knotty and really had to be cut to stringers to elimnate several knots and be usefull.  All in all turned out beautiful, like a high dollar cutting board, walnut on outside edges and then hickory with walnut alternating across the board.  Final shape will change that and the toe and tiller will be additional hickory on bottem for hardnes and wear resistance, tiller walnut and hickory for a sandwhich effect.  Final planning of template board must be done with very sharp knives in the planner at a slower speed or it can (and has for me) result in some surface splinters against the grain where it is alternately stacked.  Final sanding should reduce any obvious splinter areas and fill, cover in glass with several final light coats of epoxy will fill out the board, sanding between coats.  On the rudder I used the Okume doubled 3/8ths play and sanded and shaped beautifully.  Had I not shot it full of brads to keep from slipping apart when clamping and them putting 200 lbs of weights or more to increas join pressure it would not look like I shot it with a 20 guage, but this will be epoxied in and painted to boat scheme.  Son is a weight lifter and I have used his equipment to suppliment my multiple clamps and thus equalizing pressure across different large joined pieces (including bottom and sides to hold flat during cures).  I am hoping to be able to set up to remove centerboard during trailering to prevent chattering and bouncing with only the hauldown tied in place to secure.  Will make a storage place on board, so it will get seen some and we wanted to make it reall pretty (col say's son Pat) with thh other planned wood highlights across the deck and in cockpit done in bright fashion.

Jim

[Greg Luckett]

Jim,

Could you post a picture of the center board and the rudder...and tiller?  I am curious about how the different shades and widths affect the appearance.

I just remembered that I have a nice piece of mahogany that could be cut into strips for making a tiller or the dagger board.  I am going out to sit the different woods next to each other and see how they look.  The mahogany will darken and so will the sassafras (not nearly as much).  This whole idea is starting to spark my thinking as to trying different combinations for shading, color, and how the relative thicknesses of the strips will make it look.

I built a large rudder a while ago doing something similar to what you described except I used sheet rock screws (lots of them) to both keep the pieces in position and to also clamp them.  It worked really well, then I removed the screws, filled the holes, shaped the panel into a rudder, glassed it, and then painted it.  It came out really nice.

Thanks!

[Maria CS20 104]

We have a "finished" rudder, ready for epoxy, really nice shape, a little more rounded that what I have seen but length is a little longer as well.  The centerboard blank is ready for final planning but the guy who will do it is out of town.  I will get pics of what we have of all the construction pics. I owe everyone these already, they will include the rudder and centerboard blank that still needs final planning and sanding.  I will provide pictures of final shaping and sanding as we progress.  Remember this is really hard material, all kiln dried when in the raw and I expect my muscles and back will get a workout.  Tiller is still in the drawing phase and we are working on the how to cut small strips and not loose fingers and end up bloody.  As a Safety Manager it does not bode well to show up at work each Monday with more patches and bandages than intact skin and bone, I work a little slower but I keep my parts (mostly, blow-outs occur).  I'll get these to you and all as they come to fruition.

Jim

[Maria CS20 104]

Can't seem to post a thing in our pics, Son says files are 2 meg or more maybe need a web site with attachment, heck I do not know we will figure out.  Greg, play with the layout drawing pics and coloring in with colored pencils.  I think you will find minimum contrast with mahogeny and oak and walnut, darker woods will look better, I think it will.  Son wants the distinct contrast with light and dark, I prefer softer contrast and walnut, fir and Sasafras would lood cool and distinct, or walnut, sasafras and red oak on a three ply orientation would be beautiful as well.  I will post pics as soon as we can figure out.  Ideas?  Really would like to share the work on a new file.

Jim

[Greg Luckett]

Pics must be less than 256 KB, I think.  Once that is true, clik on the "+Additonal Options" and use the attachment option to insert pics.  I use Adobe Photoshop to modify my pics.

[Greg Luckett]

I use my bandsaw to resaw the lumber into thin strips.  Much safer than a table saw for that sort of work.

[JeffM]

Jim, just got thru posting some pictures.  Besides the 256K limit, I also keep my dimensions to 600X800.  At least, that was rule with the old software.  I like Easy Thumbnails--free, simple to use, does just what it says.

[Greg Luckett]

Greg- a layer of cloth won't hurt at all.As I also posted on another thread somewhere, I also coat the inside of the trunk with an epoxy/graphite mix ( several coats) to help make things slide a bit easier.

Charlie (and all), I just got a bag of carbon from Duckworks, then realized I do not know how to use it.  How is this mixed, ratio wise?

Thanks.

[Greg Luckett]

Charlie (and all), I just got a bag of carbon from Duckworks, then realized I do not know how to use it.  How is this mixed, ratio wise?

Thanks.

I found at the West System site and in one of their manuals too, that the carbon (graphite?), should not exceed about 10% by volume.  Since I use the pumps I am just going to use a measuring spoon that is approximately the right volume for that particular batch.  This should work I think.