allboats

lake cootharaba is getting a bit too shallow. the long walk out to the middle to get on is getting too long. and then you get the boat up and get on and you're sitting on the foils on the bottom, i ended up just sitting  back dragging them through the mud until i was up and going, then trying pretty hard no to crash. and repeating this procedure after every tack.

aside from that the boat went well, and improved over the weekend. in 10 - 12 or more it goes fine around the course. in less than that i can foil on reaches and sometimes upwind but not really downwind, and i cant point. since the setup is getting close to good, i'm starting to blame weight, 'square foil drag' and 'fat ass hull drag'. these are things that wont be fixed with tuning, though i plan to make a few changes to minimise 'odd shaped gantry drag' and 'poor sailor finesse drag'. also im getting the pocket in the sail adjusted to my mast, which may hopefully pull some draught back in the sail to line up with my aft centreboard case. i think that may give me some more height upwind. 

anyway that said i had moments of glory; like picking through a fleet of A calss and nacra 5.8 cats on a reach in 10 kts. or beating sharpies and MGs around the track in breeze, despite my shit upwinds.

on the way home some tired dude ran up the back of the trailer in traffic on the highway, doing about 20ks and we were stopped. missed the gantry (that hangs 600mm over the back of the trailer) by centimetres, broke some lights and stuf on the trailer and sheered the bolts connecting the hitch on. so while his car got put on a tow truck with some pretty severe facial modification we sat on the side of the highway wondering how we were going to get 3 M12s to get the trailer back together and get home. anyway long story short his dad rolled up to take him home, turned out he worked with my dad, (brisbane is small) so they went off on a mission to get bolts leaving me and the tired dude who'd just nearly written off my boat to make small talk for an hour on the side of the highway. fun times.

sailing

went out for a sail in gusty 15 kts with Rod from the gold coast. the boat went ok, though the flap response is still not adequate despite all the improvments. i need another change of wand to a bladerider style thing with a substantial flat bit on the end, that will pull it back propperly. also the straight wand is the way to go.
had a go on Rod's bladerider, and doesn't that make it obvious that my boat is underperforming! you just sheet on, point it, it pops up to the right height and accellerates endlessly, without spontaneously launching out of the water, tipping over sideways or sinking back down. i think i hit over 20 on his velocitek, though it may have been lying. the linkages on his boat were working overtime, while mine were kinda stopped, lethargic. it was interesting to see my boat being sailed well by someone else also, and i know a couple of things. it can go quick upwind when sailed propperly, though probably not in less than 15 kts. It looks really bulky when foiling compared to all the other boats. its like the fat kid.
resolve to put it on a diet. failing that a new hull/wings.
new bladerider sail is an improvment, needs slight luff adjustment.

wand

i did a couple of maths and realised that some of my light-air trouble is possibly stemming from my technique, rather than from setup problems. (would be great if it turns out this is the case.)

Basically when i sit at the back of the boat and try and launch, i can get up to about 7 degrees angle of attack on the centreboard foil as the bow lifts up, and my boat's fat ass drags in the water. lifting off like this the wand starts moving the flap up, as the front of the boat starts to clear of the surface. in this configuration, with the flap down say 5 degrees out of 20, the centreboard Cl is 1.57 and Cd is 0.0193
If on the other hand i was to sit really far forward and keep the nose buried, i could keep the flap at say 15 degrees down, at the same stage of takeoff. in this configuration the centreboard angle of attack is 0 degrees, but with the extra flap deflection im still getting a Cl of 1.54 and a Cd of 0.0156. so this is better, same lift for about 80 to 85% of the drag. ill try it out on the weekend.

also i ripped off my crappy wand. finally. i laid up some new bits tonight that will allow me to adjust everything about the wand, and to use carbon rod and tube of varying stiffness and size. I have a choice of two wands to start with - a straight stiff one with flexible tip and a kinked, stiff one like the old prowlers, with a flexible tip as well. ill try both on saturday weather permitting. The aim of all this is to keep the flap at full deflection while the bow is within a foot of the water. the winning wand gets glory. and to stay on the boat. it is possible that they will both lose, in which case shame will be brought apon their families. and they both also die.

testing

went out today for a few hours to test the new modifications. conditions were like 3 to 12kts. anything above about 8 i was foiling, though probably needed 10 to go upwind and downwind propperly. everything worked well, no breakages, nothing moved at all. didn't capsize or crash, but i was playing it pretty safe. tried a foiling tack and almost threw myself off the back corner of the wing, holding onto the tramp lacing with my feet. it turns much quicker on foils!

The linkages work much better, and the rudder adjutment in particular is a massive step up from what i had. the wand vibrates when going slow, which is annoying, so ill take to it with the grinder and make it flatter on one side. also thinking about a flat surface on the end, so that not as much of it drags in the water.

i need a new sail.

im not quite happy with the angle of the centreboard. i noticed that i had the rudder trimmed back, flap up about 5 degrees, to the point where half the time it was actually pulling the transom down; you could see because the top gudgeon was touching the top of the gantry, rather than there being a small gap. seems to me the rudder foil could be smaller. before i go cutting stuf im going to make an F-box of sorts, a contraption that lets me adjust the rake fo the centreboard over about 5 degrees on the fly. also i want to put a small bulb at the T joint of the centreboard, to hide a wad of carbon uni that i will wrap around the leading edge at the T. the crack didnt get any bigger, but im not going to risk breaking this foil. so there's 2 or 3 projects to keep me busy(er).

linkages relinked

just a quick note: the boat is nearly back in one bit again!

all linkages are now stainless, after much swearing at (breaking of) expensive taps/dyes. there is less slack and the ends are more robust, especially the new flap joint which is a beast. see below, pretty self explanatory. i think the bladeriders have a similar thing, with the benefit of having a nice thick bullet fairing to hide all the shit in. i reckon ill have to fair it a bit.

the main foil appears to be at a good angle to the static waterline, about +1.5 to +2 degrees; i think the flap was just jamming in the 'up' position after the linkage broke within 10 seconds of leaving the ramp, giving me that 'sucking' feeling. also theres a 10mm long crack at the t joint of the new centreboard, not sure if its superficial or not. im keeping an eye on it. be sailing soon, should be interesting.

The States

Im not actually on the same lap as matt...

1. out of control approaching the bottom mark. i was on the same lap as the scows.

2. at least i missed them.

well I finised two races, and in one of them i beat another boat.

Had a couple of teething problems as you do when your that unprepared at a regatta.

Saturday was a bit of a write-off, as it was squalling through at 20-30kts as predicted. there was one boat in a fleet of 11 which did not sustain any damage, and that was Matt with his bladerider. He sailed the boat pretty damn well for the conditions. The sheer variety of damage seen on the rigging lawn after racing was abandoned was impressive even for a moth regatta. I lost my rig, and in the process busted a panel in my pretty shagged sail. (fixed with gaffa tape) The foils were fine, but they were probably to blame for the whole 'losing the rig' caper in the first place.

I have somehow managed to stuff up the angle of atack of the centreboard, i think. There isn't enough +ve angle, which meant i wasn't getting up and foiling at the kind of low speeds i should be able to. I will fix it by increasing its forward rake, which in the long run isn't a bad thing. This means i need to modify my centreboard case thing.

The rudder adjustment systems is shit. needs a better sollution.

Both ball joints failed on saturday, and though i tried to fix them with 5 minute epoxy, they were too loaded up and snapped again within minutes. So i sailed Sunday with no flaps at all, and it was predictably hard to foil and hairy once up. I have a new 'bladerider inspired' sollution, which should work or at least look a bit pro. Means ill have to go back to stainless rod for pushrods instead of fibreglass. no big deal.

Anyway, for the next month or so I've got a bit on at uni, probably not much will happen on the boat. After that ill sort out a new mast and sail, and get to work on the few things to tune before i go sailing agian.

race ready but no sail today

its 30kts from the SE today. had a couple of odd jobs to do, could have dropped the boat down to the coast today and got a quick sail in but i decided it wasnt worth it. probably better to get some uni work done. Rigged it up as best as i could in the garage to make sure the flaps worked etc. they did, here are a couple of images.

Done and dusted

Dusted figuratively not literally. The dust will blow off on the highway tomorrow.

Missing one tripple block on the cunningham, ill have to get that on the way. The forecast is for breeze, 20-30kts, i am dobtful whether the boat will last the weekend and more doubtful about the sail. (now largely just gaffa tape) However i haven't fixed the low-rider rudder so foiling it is, and theres no backing out. The boat is literally rough aroud the edges, and obviously underprepared, but pending the success of the ball joints on the flaps (curing now) i'd say all the systems are go. [im liking this motif of using cliches in their original context] The adjustable gantry looks pretty good, though i realised why everyone else's have only one lower strut and not two; there needs to be some flex in the joint between the strut and the bottom gudgeon to facilitate easy adjustment. anyway its fine for now, hopefully i've got the angles right and i wont need to adjust it. The cams seem to work in the sail, ill wait and see on that one as well. i have a spare just in case.

gantry done pending 12 hours @ 80deg.

The release went well from the mould, by my standards. (lucky i didnt spend too much time on the mould.) The vacuum finish is impressive, the part is actually lighter than my previous gantry and 200mm longer. and intact. yay. at this point i declare the design to be good, and the construction to be good. lets see how we feel after a couple of sails...

The ball joints on the other hand were a complete failure, i tested them with a good solid yank and they came off. will swage copper ones tomorrow. also got the rudder gudgeons on. 6 jobs to go.

sucker!

My $150 ebay vacuum pump came through with the goods!
im bagging everything form now on! something to bag, ill bag it. fibreglass, oranges... small animals... lock up your pets!

yeh anyway so i had a couple of small issues getting it to work, seeing as it was my first go, and the job was quite complex. i think that box was the most complex thing i've ever laid up; it had lots of different ingredients and was awkward to get your hand into. My main problem with the vacuum was in the spikiness of the mould. You wouldn’t think so hey. The spikes, nails, bits of glue/bog etc made a couple of little holes in the bag, and i tried patching them up with tackytape. Didn’t work, so i got a whole new bag (garden strength garbage bag) and put the whole mould and bag in that. Taped it up. sweet.

Carboned up the other bit of the gantry, the two tubes. Also stuck some little globs of glue in the exact right places on the control rods in the foils to serve as the balls in my flap ball joints. Got the stainless T piece welded also, thanks to Rod at Astro Metal for being a good bloke.

8 things to go on the list.

working parts

tried out the vacuum today, seems to work. will have a more definitive answer tomorrow when i 'bag' the gantry.

otherwise on track to be done for thursday night hopefully for a sail on friday!

rigged up my flap adjustment systems, the rudder system is a bit questionable. not sure if i have gone forwards or backwards with that one. (the extra bits on the rudder are the remains of my old system; im not prepared to write that one off just yet.

The centreboard control mechanism needs a taller mounting block to attach the cable to the cockpit floor, and i think ill bodgey something up there cos i already have the gear to stick a rod through the boat bladerider style. just not the time. there is more friction than id like in that system but at least not too much slack.

Overall im pretty happy with the new main foil, which is now completely done sans ball joint. The top skin hinge is neat, and flexes really well, and the gap closes up completely when the flap is at full deflection. I have an issue with some .5mm lips on the top surface around the hinge, due to my not laying the kevlar up in the mould, but tacking it in later. not top priority though. if it survives one regatta i might think about fixing those.

pretty hectic day tomorrow of uni and gantry, with a few vacuum bits still to get. we'll see if i cant stuff up my schedule.

a sigh of relief for the foils are done...

pretty much anyway.
a few cuts here and a few holes there, a bit of sanding.



the rudder is strengthened almost to the centreboard spec, it will hopefully be strong enough. (in its defence it is 2/3 the area... your honour.) i made it shorter beneath the boat so its foil travels 60mm above the line of the centreboard foil, and out of its downwash. there will be a reduction of the torque on the gantry from steering and foiling high, and also it will help the foil ventilate in a crash and thus not snap. we hope. and since there is not so much rudder in the water when foiling high, it will reduce my tendency to jam the tiller towards me to bear off before crashing, as that little bad habbit was breaking things... well reduce it by making it pretty much ineffective. hopefully my new reduced friction centreboard flap will help in that respect too.

Now for the gantry. The QLD moth states and my deadline are fast approaching (we're inside a week) The gantry should take 3 or 4 days to put together so i may even be able to rig the boat before the regatta. ha! as if. I bought a vacuum pump off ebay today for $160 bucks, which i think was an ok buy, and its in brisbane too so ill pick it up tomorrow, get some tacky tape on monday and be sucking on monday night. in the mean time i need a jig to get the angles of the tubes right and get them glued/carboned together.

other than that i need to fix the hole in the boat (i bought a clear bulkhead cap for it, stuck it on, but it was a tight fit so when i tested it after the sikaflex had dried, i realised it was squashed and the cap wouldnt screw in.) (try again timmy. Timmah!) I need to get my welding bloke to weld my little stainless gudgeon for the gantry lower attachment, i need to get a batten for my sail, and i need to make those fiddly little ball joints that attach the rods to the flaps.

and that is all.

Bell Cranks and linkages

Knocked off a few niggling little jobs today. It's been hard to work around uni and last night was my first good sleep all week (3am - 11am). will be no such luxury tonight, this counts as procrastinating and i have a meeting at 1pm tomorrow (sunday!) and about form now till then worth of exploded axonometric diagram to do...

Anyway i got the bell cranks designed and cut out. All the linkage bits i pretty much thought up as i went along, though i had a vague idea of what i wanted; they definitely had to be bigger than before, and i wanted to minimise friction and slack as much as possible. The little carbon forks on the fibreglass rods I think were a good idea, easy to make, we will see whether they hold together or not. they look pretty tough anyway. My little stainlless threaded fork is an M5 turnbuckle body that i cut up, and took about 5 minutes to make with the grinder. The thread is done for you its great.

I also took the opportunity to finish off the cams and do the wand as well. The centreboard system is pretty done save a bit of bog and the ball joint on the flap. Im waiting until I've done the gantry before i cut the rudder to length and put its linkages together.


I checked the centreboad foil angle of attack today too (first time in the boat) and its what i wanted (good management more than anything i think!) between +1.5 and +1.8 degrees on roungh calculations. Much more than that and you start paying drag penalties, but form memory up to about that range you only gain 1% or 2% Cd but significant Cl.

Also i went to pick up the carbon tube I got from CST for the gantry from the post office as i was out when the courier rocked up (as is always the case) but the post office is apparently shut on the weekends??? wtf? how backward are we! I now get the whole '5 working days' thing. There must be an easier way to get something from one person to another... in this day and age.

It had a baby and then the baby had a baby.

What i am of course referring to is what is by now one of my favourite things to do; pulling a mould of something out of the oven and then pulling some nice looking carbon bit out of the mould. and intending to wait until it is cool to open the mould but not having the patience and getting burnt. and in this case dropping half the mould on my toe.

cool. so randemnity aside, i have, for the most part, a foil. the flap works after a bit of cracking of stray bog, and the recess i made in the mould (at the T joint for the flap) came out perfectly.

The oven sat on 75-80 degrees for 24 hours, last time it was summer and it all got a bit hotter, more like a solid 80-85. and the resin loves that, so consequently i haven't got the tesnile strength in the resin quite as good. and it has a different, dull pitch when you knock it. but its still ok. that coupled with the better lay-up and a couple of other dirty tricks i have up my sleeve (rubs hands together) should hopefully make this one not break.

so also the top hinge worked well. The kevlar is 2 layers of 75g, one at 45 degrees, so its pretty much exactly as flexible/stiff as it needs to be. as you can see the gap closes up pretty much prefectly when its fully deflected, which will be fine, as id say it will create turbulant bubble at the kink and be pretty efficient. with the flap up at high speed the separation point on the bottom surface is well forward of the gap, so no real drag there either I imagine. Thats my (probably ill informed) justification anyway. wait and see.

sandwiched

laid up all the carbon on friday, laminated the 3 bits together today. went fine, im happy with the amount of material, though this time i didn't reinforce the skin so much at the exit point and at the T-Joint. There was still ample weight of carbon in those areas but, the weakness last time was in how i dealt with the shear loadings.

Anyway i've improved the sheer resistance in a couple of ways, the result of which will hopefully be a long as prosporous, successful life for the foil: (carreer as a banker, hot wife and a couple of kids, townhouse in central sydney, big boat etc.)

• First of all the T joint has no foam in it at all, just glue (sp microfibres). Last time it was foam and bog (Q-cells) with carbon strands in it, that wasnt enough.


• There is some diagonal carbon along the front and back inside edges in the areas of high shear stress - i just chuked it in there with a big glob of glue in the middle; the idea is that when the mould squeezes together it gets pushed to the places the glue is oozing out.


• you can see in the photo I integrated my carbon T-piece into the bottom surface, that pushed straight up into the foil and is encased in glue. hopefully there is no way in the world it will separate from the bottom skin, or pull out of the strut.


• Lastly i plan to further tie the leading and trailng edges of the foil together around the T joint area and the exit area by making carbon 'wet bolts', at about 30-50mm centres for about 250 - 300mm, to join the top and bottom surfaces. ill put photos of them up when i do them.

Also i cut my finger twice in the same spot with the grinder. first time with the cutting disk then again with a sandpaper disk. the second time it went straight through my nice fresh band-aid. I put a heavy glove on after that. When you wear a glove you might as well have a bit of wood for a hand.