Team Seacats

I launched the boat yesterday and sailed it twice. It was an outstanding success! She handles very well with only a bit of weather helm (this is desirable from a performance standpoint as far as the underwater foils are concerned). I’m fortunate to have this pond on the property where I work so I can take it out at lunch or after hours. During lunch, the wind was a bit fluky but had an occasional sustained 8 knot puffs come down the lake. She remained dry as a bone inside and the rig / sails look exceptional with a bit of pressure on them.

Later, on my way home at about 7pm, I drove by the upper pond and the wind was a nice steady 8 to 10…a quick call to Bonnie to relay that I wasn’t coming home just yet, and I was sailing again 10 minutes later. 10knots is getting to the upper range of this rig and I took a couple of knock-downs going upwind where the boat laid over and I lost helm until I eased the sheets. After a long upwind beat and another tack, suddenly the boat felt terribly unresponsive and I began to wonder if I was having radio trouble. I finally managed to get the boat to bear away and control did come back. I decided I would make an inspection so I pointed the boat onto a reach back at me. I immediately noticed that the mast was bending off to leeward and upon inspection, found that during tacking, if the sails flog a bit, they can shake the shrouds out of the spreaders (spreaders are slotted … it’s a long story). A little tape or thread holding the shrouds to the spreaders will solve that.  I also realized that I forgot to cover up the drain hole in the upper right corner of the stern.  However, even that didn’t allow in a single drop of water even through the knock downs and excessive healing.

We took some video this afternoon and I’m doing a little editing on it – will probably have it up by the end of the week.

The mast and sail rigging is complete now and the only lines left to run are those to the main winch servo.  I hope to work on re-installation of the deck hardware this evening.  The main sail and jib sail clew attachments to their respective booms is done by means of a rubber grommet that tightly fits the .25″ carbon fiber boom.  They fit tightly enough to not move under line pressure but you can slide them up and down the boom manually to adjust the angle of the clew attachment for better sail shape control.  The jib tack is tied in place to the leading edge of the boom, but the head has a tension adjustment on it.  As for the main, I have temporarily tied the main downhuaul in place but will work out some sort of adjustment on this in the future.

The vang worked out particularly well and the carbon fiber bowsie presents a great deal of “bling”.  All long line terminations at this point are neatly spliced – no knots unless they are on extremely short lines (like the ones holding the main sail to the mast or the ones wrapping the grommets).

Lead is heavy but it flows almost like water when it’s molten!  I found this out when the old mold half (on it’s second cycle) cracked mid-pour on Saturday.  As you can see evident in my pouring stand / setup, I was concerned about this possibility and wanted to take precaution that molten lead did not end up on me.  I put in a blast shield constructed of 3/16″ plywood and an old towel in the workbench to shield me from the pour…good thing too.  As it turns out, when the mold cracked (ever so slightly), the lead went between the mold and the plywood and just pooled and cooled there.  I gave it just enough time to cool and seal the crack before I finished the pour.  The crack should not have been result of moisture in the mold because both halves spent 1.5 hours in the oven at 350 degrees.  However, this mold half was showing some hair-line cracks and that’s why I built the other half mixing in strands of fiberglass into the Rock Hard Putty.  Although it needed a little extra finishing work, I still ended up with a usable bulb.  If you recall, I also made a slot in which I could embed a piece of the same aluminum extrusion that forms the keel strut.  I was quite concerned that I wouldn’t be able to remove the aluminum piece after the pour, but it came out with surprising ease.  No tools required.

 

I still feel obligated to remind you that lead is a dangerous substance to work with.  It is toxic to the body and presents a very serious burn hazard in molten form.  If you work with this stuff, be sure to protect yourself from the shavings and dust, wash hands, and be overly cautions when it’s hot.

More later, good progress made this weekend on rigging and keel fin.  Maiden voyage might just happen this weekend!  And yes, for the last time, sans a few accent stripes, that is the final color (why does everyone keep asking me that?)

After seeing an “early show” of fireworks on the 3rd with Bonnie, the 4th provided a solid day of work on the one meter.  I set out first thing to make the little pulley block I had dreamed up the other day.  While I did save $10 by making this thing myself, after the first three tries, I had almost 1.5 hours invested in it…the next ones will be faster!  I used some .030 aluminum plate and cut out a simple flat shape, drilled one hole, bent it, drilled the sister hole, cut a piece of 1/8″ aluminum tubing to fit the center of the sheave, and assembled with a 2mm screw and nut.  It sounds simple but it took several attempts to get the bend right in the middle and I finally discovered that it bends perfectly around the end of a pair of forceps.  A small hole in the middle of the bend provided room for another 2mm screw to fasten it to the deck.  I suspect, however, that I will need the aluminum plate to extend beyond the top and further back to keep the line for shaking off the sheave and jamming.

Because the aluminum mold is a bit delayed, I also worked on getting the putty mold repaired to cast another bulb or two.  If you remember, this mold was poured in two parts using a PVC plug in the middle suspended in a box with a screw.  The first half that was poured saw the air bubbles suspend at the surface right against the plug.  There was really no way for us to eliminate them.  The second half did just fine since the plug was at the bottom of the pour.  The air bubbles caused a problem when I poured the lead and the rapid expansion of the air in those pockets caused the mold to chip out.  I used the old top half, without the air next to the mold surface, as a new bottom, and poured a new top – I put fiberglass in this one to help with some of the minor cracking that seemed to happen too but now I wonder if that didn’t trap some air bubbles near the mold surface again.  We’ll see when I pour again.  This time around, I attached a small section of the keel spar so I can maybe leave a piece in the mold to create the slot I need to attach the real strut when pouring the lead.  With any luck, I’ll be able to extract the aluminum piece from the poured lead leaving a nicely fitted opening.  I have some doubts that the aluminum will come cleanly out of the lead though.  This way I could get more precision with the slot.

While that setup, I finally installed the rudder servo in the underside of the deck.  I realize that most things need to sit down low, but this is a very small light-weight high-torque micro servo and it really reduced the amount of linkage needed to get it to drive the rudder.
  Because the screws would be really difficult to get at for the servo arms, I made a fiberglass / balsa box that glued to the underside of the deck that had grooves for the servo mount flanges and a cover that screws on it to box in the servo.  It works great and has no play.  I also decided that I really didn’t like the ratchet action of the sail control stick on the new radio (usually intended for throttle on an r/c airplane) and wanted a smoother action.  I discovered that if I take the ratchet detent spring and flip it over, that it gives a much smoother action and still provides enough resistance so the stick will stay where you leave it.

Next up was some filler on the hull half joints and a few minor imperfections.  Before I did that though, I marked the location of all the holes and hardware and took photos to have documentation so I can find them later if they get covered up in the finishing process.  Finally, a coat of primer.