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Danny Boy

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Everything posted by Danny Boy

  1. I've got so many ideas for an unstayed una IC that I'd consider selling a kidney on the black market to finance it. Shit I hate the way that boats bleed you dry but I can see it will always be that way.
  2. BalticBandit, I'm not completely down with some of the stuff that you're saying here. I agree that generally you'd possibly sheet freer on a gyber, as if you take the AOA as the angle of the sail to the track rather than the centre of the boat then this would be consistent. The second thing to realize is that an increase in boat speed on a high aspect foil, even a slight increase in boat speed, results in dramatically more lift. 49ers experience this a lot. Off the line it is important to be able to get your nose out so that you can ease your jib sheet about 2" at the lower sprea
  3. To be honest I reckon that the finn/europe masts are so constrained by their rules that the external dimensions are pretty much fixed and there isn't much difference between the top guy's kit - I believe the europes post '96 tried to word their mast rule to create a 1 design (female) mould situation in order to control development costs, but I think a certain nation applied the sledgehammer approach and made its own tooling at vast expense, making a bit of a mockery of the rule. From these same moulds different sailors can specify different layups to suit their required bend characteristics,
  4. I think we're all singing from roughly the same hymn sheet. Dynamic reponse is just response to anything dynamic, whether gust or seaload. Like you say most wave encounters are pretty "transient" or quick - often too quick to trim to. Gusts are usually slower, although a decent rig will soften the effect of the gust, "automating" the rig. The stiffer mast whipping about imparts more force back onto the boat if it is stiffer due to higher sectional weight (i.e same material, same diameter, thicker wall). If the mast is stiffer due to either a different section shape (larger diameter, thinn
  5. I used to be a pretty serious Laser sailor, that most technical of classes. I mostly windsurf now but dabble a bit in other stuff. I believe one of my best mates is your cousin Tim..
  6. Andy P – I can understand that an actual windsurf rig, even stayed, would be far too bendy and the sail shape all wrong for the canoe, which has orders of magnitude more RM. Absolutely hear you re: the mast weights – my belief is that an unstayed canoe rig would have to be proportionally stiffer than the finn rig, therefore weigh, say, 10+kg. Obviously this is not a trivial amount of weight in the context of a 50kg canoe, nor is the cost of 10kg of carbon/epoxy… Just to illustrate, I reckon that a finn and moth with appropriate sized sailors would generate similar sized RM, so a unstayed mot
  7. Sorry Chris - good point which I forgot in my rant, cunningham acting like a backstay on the bendier stayed masts. Taken to the extreme of a windsurfer rig the sail is set entirely on masses of downhaul. Less of an effect on my flight of fancy really stiff unstayed telegraph pole! Not sure whether the sleeve luff camber sails are any more efficient than a decent wing section mast. Obviously then you have to reconcile disparate aero and bend requirements. Either way, stiff or bendy mast with stiff battens and lots of cunningham means rigid camber is set into the sail which doesn't "feather"
  8. Speng is right about the sloop rig and the higher Cl due to it being a "slotted wing" but this only really applies upwind where the jib can be sheeted correctly with the slot working. Much lower than this and the jib cannot be trimmed efficiently, especially on a narrow boat like the canoe thereby negating this effect. Down towards the dead run the jib is both blanketed, and a horrendously inefficient shape, hence the relative superiority of the una when sailing deep. Upwind, all things being equal the sloop should be better until all of the righting moment is used, as the max Cl availab
  9. OFP, Sorry I probably wasn't clear enough on the sheeting angles. What I was referring to was the optimum sheeting angles when the sails are pinned in sailing upwind, i.e when the helm is steering to the telltales with the AOA of the sails constant with respect to the centreline. The optimum sheeting angle would be the optimium jib lead angle for a sloop where upwind generally the main will be centred to keep the slot open. For Una rigged boats this angle is the boom to centreline angle (Una rigs i.e finn, laser) A mirror dinghy will have a fairly wide jib sheeting base, whilst an IACC yacht
  10. Gents. The reason that gybing daggerboards work (if done properly) is this: The sideforce that opposes the forces from the rig and propels the boat forwards is provided by the daggerboard, but also the rudder (usually by virtue of a couple of degrees of weather helm, as the rudder operates in the downwash of the dagger), and the hull, which usually has a lateral area of comparable size to the dagger. Whilst the dagger and rudder are fairly effective lifting devices (high - ish aspect ratio, good section shape) The hull is a highly inefficient lifting surface (very low aspect ratio, dodg
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