Boom shakalaka-boom

Ok, you got a better song with Boom in the lyrics?

Today it was time to pull out the old mast segment we’ve had squirreled away and start creating the main boom. This stick is 18′ of a salvaged carbon mast. The section may be overkill but if we leave it as is, it should be a hell of a strong boom. One option is to cut away the last three inches off the skinny side and form a new, much lighter lower edge the whole length. Or we take Mike Leneman’s simple suggestion of making Swiss cheese holes all along the boom. That would also save weight and make it easy to run reefing rigging internally. And we also need to think through making sail catchers that stick out about a foot on both sides of the boom.

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We started making a forward end bracket to bolt inside this boom, which will provide a strong pivot pin attachment to the gooseneck on the mast. One big bummer is that goose is already bedded and bolted to the mast at 54″ up (for the Shuttleworth it was commissioned to) but we need it a foot lower (that would get it to the level resting position seen in these sawhorse holding photos). Can’t really do that mast work until the boat is out of the workshop. Hmmm. The next update should have that boom end bracket to show you. And yes, the boom in this position shown is 6’3″ above the cockpit floor so fewer whacked heads expected. It’ll be about a foot above the hard top, leaving room for some solar panels up there.

The rudder came out of its final carbon layer vacuum bag this morning, looking good (and big next to a grown up!)

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The yellow strip is a Kevlar piece to help make the leading edge tougher against hitting small stuff in the water. I’ll do a bit more final fairing on this board over the next couple of days and then it will be time to make the scary cut into it to creat the trailing edge trim tab. Cover your eyes, Mertyl, this one’s not for the faint of heart.

The boat has suffered some October down time due to excessive viewership of the SF Giants run. The prudent move would have been to purchase 10 gallons of epoxy, but instead the $ went to tix for Bumgarner’s shutout on Sunday.
Great time with Griffin!

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But World Series parades also mean it’s time for the weather to turn. Cold epoxy does not flow well, and I finally thought it through – make a winter warming hut! This simple box (old Sheetrock and leftover styrofoam) is now keeping the fluids at just right viscosity, with an air temp in the upper 70s. Venting the box more or less lets us modify the temperature and therefore adjust the go-off timing of the epoxy hardener. REALLY wish I had spent the two hours on this box two winters ago :(

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It’s warmed by a simple incandescent 60 watt bulb under an aluminum plate holding up the bottles.

Good things are happening building out the aft cabin furniture. Photos to come once the bunks are bonded in. Yes, doing some work on the inside even though I said no cabin work until all exterior parts are complete. Thankfully it means we’re getting to the end of the outside stuff and can see the light towards the winter interior build. We’ll skip the Giants parade and work on the rudder!

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Wind vane and rudder progress

The shop neighbors who were perplexed by the stern tower were satisfied now by seeing the self-steering wind vane installed. It’s the brown unit in these photos. The actual vane that gets pushed by the wind is in a deeply “reefed” position, tilted way back to fit under the skylight ceiling.

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The rudder control cables come thru the tower shelf and will get tied to the legs and then routed to the (to be built) yoke atop the new rudder’s trim tab pivot pin.

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We’ll get back to those details in a couple of weeks when the rudder cassette is built.

The rudder has been shaped, wrapped once in bi-directional carbon and had the 14 layers of carbon unidirectional cloth added in the recessed channels down both sides of the board. First, here’s a look at how that embedded pivot tube just fits inside the shaped rudder.

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And underneath the white fairing compound you can just see the staggered layers of carbon uni.

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The only unexplained part of the rudder plans is how one would keep the blade’s curve intact over the area that gets cut out of the foam core and replaced by that big carbon-wrapped spine piece. So we have a flat spot there that I’ve had to build back up with fairing compound. I’m doing the fairing work now, before adding the final outer layer of carbon wrap.

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Ok, that side is done and we’ll need a few fairing sessions to finish the other.

While the rudder layers cure, work progresses on prepping the windshield and hardtop for paint, and the floors for the aft cabin and equipment room. Pictures soon.

Charlie gets sucked in

F27 owner Charlie Jeremias apparently didn’t get too turned off during the SoCal TaTa rally with me prattling on about the boat build; in fact he wanted to come work in the shop. So we figured a good day of vacuum bagging work would be fun. (Now if I could just get him back here to do the fairing…)
We tackled the last of the net lashing tubes – the 14′ sections on the float decks. Here’s the 3/4″ PVC bonded to the deck with epoxy putty fillets:

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Then I had to hurry with the wetting out of the fabric rolls as Master Glasser Charlie confidently laid out the 3 layer lamination:

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Here we’re ready to add the peel ply, perf’d film and breather before closing up the bag:

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Then with the vacuum pump running we focused on the replacement carbon tube to encase in the rudder stock (next topic). The next morning I happily unpacked the bagging supplies from the float deck to see our new net lashing tube bonded in place. Came out just fine.

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Once these tubes get faired and we cut the notches (same as was done on the beams and main hull), the float exteriors will finally be DONE!

Now back to the new rudder. At least the $100 Rockwest Composites carbon pivot tube showed up within 48 hours, so we’re quickly back in business. Charlie cleaned out that channel in the foam core to reset the proper depth. This time I used a more viscous epoxy and cabosil mix and pushed the tube in to a shallow puddle, and let that cure overnight. The next day saw further filling of epoxy mix to encase the carbon tube.

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Now it’s game-on; get to shaping the rudder out of the foam core stock! This time I only cut three depth lines with the circ saw and went right to the power planer. The long process I described months ago on the first rudder was cut down by about 75%, and this one is being shaped better too. But of course if you don’t mind the power cord, the machine quickly chews it up.

20141012-000509.jpg under the cord in that photo you can see the depth guide lines cut where the rudder face will be 1/2″, 3/4″ and 1″ out from the centerline. Didn’t bother to spray paint in the grooves this time as they are easy to spot as you plane away the stock. The trick is to leave a good 1/8″ or so to do by hand (shur-form) and not take the planer down to the depth contour line. Also, looking at Jim Antrim’s plans for the rudder trim tab I knew that carbon pivot tube would be close to the newly exposed rudder skin surface. Sure enough, you can see that it will lie about 1/16″ in to the remaining foam area. Tonight I back filled that channel back to flush with the rudder face – but here it is before filling in the gap:

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Tomorrow we’ll finish smoothing out this first rudder side, and when satisfied with the shape we grab the carbon fiber 12 layers of 6″ wide that needs to have more of the foam core rebated back to add this stiffener fabric. That step will make more sense with tomorrow night’s photos.

Stern tower finished

Here are a few more views now that the equipment tower is fabricated and faired. It will be getting a second horizontal ‘shelf’ but we’ll wait on placing that until figuring out if an electric tiller pilot (remote steering) can be mounted back there. This would be in addition to the primary windvane (no electricity needed) self-steering gear. We need to have the completed tiller in place first.

The legs have thru-holes for lifelines:

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The top is a carbon deck and a simple hollow box below with access ports to hide the equipment fasteners and wires. The hole in the center of the platform is a channel to pass the windvane’s control lines down to the rudder trim tab. And the horizontal stick out the back is a little gantry for lifting and holding the rudder out of the water once docked or anchored. The ear flap on the starboard side is for the radar; the port side is flush son you can get to the aft steps easily.

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I’m actually getting sick of the splotchy fairing patches look on all these big parts. It’s about time to get things primer painted so a cohesive boat begins to emerge. But we shouldn’t touch any painting until the fabrication work is complete.

After the Jim Antrim meeting the steps on building the integrated trim-Tab rudder became clear, so work is underway. During careful placement of the 5′ carbon hinge tube, we had a “runaway thermal event”, meaning Greg blew it by trying to bond the 7/8″ carbon tube in to the centered 1 9/16″ channel cut into the foam core, and expecting to have that work in one fill ‘er up with epoxy putty pass. As I was seating in a uniform depth, the mass of wet epoxy down at the bottom was too great and it superheated quickly. Realizing the problem, I tried to yank the whole tube out and quickly evacuate the putty. Instead the carbon melted and bent the tube that needs to stay arrow-straight. What a huge mess, along with the panic of losing the very expensive 2 1/4″ shaped foam core and triple layer carbon spine. Here’s the work before the meltdown.

20141006-235307.jpg that’s the spine about to be bonded in – 3 layers of carbon around high density foam, then center the whole thing in the low density rudder core. Also see on the left side the marks for the trim tab – it’ll be 4 1/2″ of the 16″ wide rudder and run about 3′ vertically.
So Monday morning began with another $100 sent to Rockwest Composites in Utah to replace the pivot tube. Monday night ended with a nasty two hour job of extricating the ruined tube and hardened putty from the soft rudder core. skilsaw, router, grinder and multi tool teamed up to make a fantastic mess but in the end the channel integrity is back and ready to take the new tube once the UPS truck drops by. We’ll do the bonding in multiple stages this time. Another expensive lesson learned.