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Walt S.

Spindrift 12 build log

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I'm fairing this week.  I have planed down the chines and rounded them over and then sanded with a fairing board to ensure waviness was eliminated.  I planed a 3/4" flat line down the keel line and 1/2" up through the stem where I expect to attach an UHMW shoe keel guard.  Today, I'm going to try fairing some spots with microballoon/epoxy putty.  

 

I'll try to finish fairing by the end of the week or when I give up, whichever comes first. 

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I dry-fit the fiberglass today overlapping it about 1 1/2" at the keel line.  Pictures to follow.  I'm going to start finishing the foils.  Dave and others have pointed out that you want to completely finish the centerboard (glassed, primed, painted) before gluing the centerboard trunk together so that you know the centerboard will fit. 

 

Does anyone have a source for soft single-braided 3/16" dacron rope?  I want to make the leading edge of my foils epoxied dacron rope. 

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Welp, I started glassing at 8 last night and didn't finish until 2.  I should've mixed larger amounts of epoxy and squeegeed more before rolling.  It has been 10-12 hours since I put the last coat on and the epoxy is still sticky.  The ambient temperature is around 55 degrees F and it got much colder last night even with a space heater.  I'm going to have to wait another several hours for the epoxy to get hard enough to put the fill coat on.  This time, I'm going to mix in larger quantities (8 pumps each of resin and hardener) with microballoons and spread it over a wider area faster with a squeegee.  The glass job looks pretty good though, in my opinion: no waviness, no air bubbles.  Again, I faired the hull before putting on the glass which is the way to go.  I gave everything a final downward squeegeeing before trying to sleep (I was unable), so there were no drips or runs. 

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You should be able to get dacron line at West Marine or any similar store.

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I finished glassing the boat.  To fill the weave I used a bit of cabosil (about 20 - 25% of the volume of epoxy), then rolled and squeegeed it on.  I waited a few days, sanded, and applied a hot coat running a heat gun slightly ahead of the tipping brush after I rolled it on.  Here are the results.

 

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Today, I planed the leading edge of the centerboard down to 3/8" width and dry fit the 1/4" nylon rope.  It turns out that the rope at the hardware store said "Nylon" but the inside packaging said 'Nylon, Polyester, and Polypropylene."  The latter supposedly does not bond well to epoxy, so now I'm going to have to drive half an hour to West Marine.  While I'm there, I might as well get varnish and paint.  If any of you reading this want to know why and how to put epoxy-saturated rope on the leading edge of your foils, read this featuring references to forum greats Tom Lathrop and GRaham Byrnes. 

http://www.duckworksmagazine.com/07/howto/foiled/index.htm

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Instead of a flat, ground into the lead edge for the "rope trick", I prefer to use a shallow groove, done with a cove bit, which helps self center the line, as it's being stretched taut around the blade. 

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I routed a groove in the edge, too.  The rope is half buried.  I used a centering jig on the router, two brass pins that screw into the base.

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I used Alan's simple method for scraping the groove with a sharpened screw head.  Worked great.  See his CS 15 video #14 at about the 1:30 mark.

 

Bob

 

 

 

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I ended up leaving it flat as I didn't see these updates before I got started.  It centered fine except in one small section.  I faired it with cabosil the next day.  The way to do it more precisely is on a router table.  I liked Dave/Hirilonde's method of cutting the groove on a router table and installing the rope before shaping it.  He shows this in his Lapwing build.

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You boat is looking good Walt. I was just reading about your plans of reinforcing the chines with some sacrificial wood. Have you considered using Kevlar fabric to protect the chines?

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Roam,


I considered it but think that the fiberglass will be tough-enough.  I filled the weave of the fiberglass with epoxy and cabosil.  It's so hard to sand that I wonder what further abrasion resistance is necessary.  I don't intend to drag it up the beach on its chines.  If it is just leaned over gently, the fiberglass should be hard-enough. 

 

The keel and stem are a different story.  I could see my boys having trouble lifting the boat and dragging it on its keel.  For that, I intend to screw in some HDPE over a bedding compound, though I haven't figured out which.  Most people here are using a hollow back on the keel which tends to run about $10-12 a linear foot and adds more weight. 

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I intend to post some more pictures today or tomorrow.  I finally finished epoxying the centerboard which ended up slightly wider (not thicker) than I would like due to the rope used on the leading edge, so I spaced the kingposts an extra 1/8" across the centerboard trunk.  I glassed the insides of the centerboard trunk, filled the weave with epoxy and cabosil, sanded, and hot-coated.  It seems plenty tough.   

 

This part of the boat build drags out quite a bit.  I'm trying to figure out where to put the dado slots on the trunk stiffening beams and am garbage at reading plans.  I am probably going to put the beams on then put in a 3/4" wide by 1/4" deep dado with a 1/4" routing bit on my Dremel.  A router table or table saw with a dadoing blade would be nice, but I don't have them. 

 

I'm going to keep the centerboard trunk in two halves so that I can position it on the deck and outline where the centerboard slot should by tracing one have of the inside centerboard trunk and then the other.  Then I'll cut it out with a jigsaw and glue in the trunk. 

 

Again, this part is dragging out owing to kids, number of coats of epoxy needed, work, etc.

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The inside of the centerboard trunk is now 1/4" wider than the centerboard (width, not thickness). Maybe I pushed the kingposts out too far?  I'm thinking of building up a 1/16" layer of epoxy on the inside of each kingpost to make the centerboard fit more snugly.  I'll make a gutter by using the thwart beams coated on one side with some packing tape so that I can pour thickened epoxy in a 1/16" gap. 

 

 

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Sorry I don't know which one, but one of Alan's videos of his CS15 build shows the gap he has for his centreboard and there is some gap.  In the video he points out that, while sailing, the foil is generally pushed hard against one side of the trunk so there is no rattle due to the space between the trunk and the foil. There is a good visual and explanation in that video. 

 

Matt

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Walt, 

I don't think you'll have any issues whatsoever with a 1/4" gap fore and aft. I think in fact it is desirable because it just makes it easier to put the board in and take it out. Close tolerances are the enemy with centerboards and hatches because they always seem to jam. 

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An 1/8" gap on either side is fine, though much bigger and you could expect some humming, without a slot flap.

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