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Looking up is apparently something that we didn’t develop through evolution. I’ve nearly made a similar mistake - it’s easy to do…please remember to check for overhead power lines when setting your boat up in an unfamiliar area - particularly with boats as portable as our catamarans. Click the image for another all-too-familiar sad story.
Hull #2 of The Bogy is nearing completion as fellow designer, Neville Cork, is finishing up the body work on his ideas of the deck layout. The rear sugar scoop extends much further forward than mine and his hatch opening is longer but narrower too - I’m looking forward to seeing his final thoughts with regards to control lines and he’s apparently got some trick for sealing the hatch that I can’t quite make out in this photo.
Neville had previously designed a skiff-style US1M that he brought out and we did some sailing against on Saturday. These two boats were very different in design philosophy so it wasn’t a refined “test” but the Bogy clearly had a performance advantage. I look forward to getting it up against some other US1M boats. In an unusual departure from standard, I didn’t take my camera along and only had a camera phone. Here’s the only sailing photo for the day, which inconsequently, also shows a dragon fly on my head.
I know this isn’t entirely sailing related - but this came from NC Doug over at the Catsailor Forums. Quite a bit of engineering going on here - how far do you think it traveled? Reportedly, the rear tires had 160psi in them to keep some shape in them.
We had our non-regatta this weekend where a bunch of F18s and who-ever else gathered to have some very informal racing. The race committee might keep track of who wins, the finish line might be a no-wake buoy, or we might do a distance race where the committee boat could drop a mark anywhere on the lake (during the race). Whatever happens and whatever the weather, we usually have a great time. This year was no exception and again Rick Harper hosted a great cook-out and pool party at his house. Personally, I find the informal racing as a good time to experiment with the boat when I probably wouldn’t try something so different in a formal race. This year, the wind was lightish so we decided to single hand our boats and ended up with some fine and very tight racing. We did have times of good breeze and Saturday morning we picked up crew at the Lake Keowee club so we could double hand. On Sunday, just before heading home, David Lennard and I put on the Layline graphics on the Layline F18 (Mike Krantz and David Lennard) and I must say that I’m quite proud of the result. Looks sharp doesn’t it!?
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).
So the fin is roughly patterned. I learned a bit making this and although the final versions will be made from a mold, I’m not convinced that I can achieve an high level shape to the foil using this method from which to make the mold. It’s close, but it’s not perfect.
I started out by laying up and vacuum bagging a sheet of carbon on a waxed piece of Lexan. Two layers of 5.7oz fabric were followed by two strips of 1″ uni-directional carbon tape, wetted out with epoxy, and allowed to cure overnight under suction. I then trimmed the sheet, leaving the tape in roughly the middle of the cut sections (a little bit forward to accommodate the offset foil shape…that will make sense in a minute). I then took the aluminum strut and drilled a series of 3/8″ holes and countersunk them significantly. The holes are to allow the filler epoxy through so it can bond to both sides. The bond of epoxy to aluminum can be good but it is sometimes suspect and this should help ensure a very good bond. Besides, the aluminum adds practically no strength in this part of the layup.
I then masked off the carbon sheets as to not scratch them or get epoxy on them, mixed up some resin thickly with microballoons and black die, and slathered up the leading and trailing edges and the aluminum strut taking care to fill in the holes. I then applied a bag of clothes pins to the trailing and leading edges one by one working my way down the foil to pinch the ends together. I moved them around slightly during cure to try and avoid visible pinch points. Once that was about 80% cured, I came back and filled the front and back hollows between the strut and edges with epoxy mixed with microballoons and chopped glass fibers and again added black die to the mixture. Everything set nicely and the foil looks pretty good for a first attempt. In hindsight, making a tape hinge and closing “the book” around the aluminum strut for the trailing edge would have resulted in a much more consistent trailing edge. A good bit of the front will be shaved off as I shape it to a decent foil shape so it wouldn’t have mattered to have a few minor pinch marks there. You can still see some irregularity from the clothes pins.
I still need to do considerable shaping to the leading edge and fair it to the bulb and the hull.
