Ncik

http://carbonchandlery.com.au/ can supply flying ant masts.

Not necessarily... https://www.theguardian.com/lifeandstyle/2018/may/26/superyachts-something-goes-wrong-raise-the-anchor

Hypothetical component + density trickery = as many foils for testing as you desire. The trick will actually be to design only good ones so testing time is maximised and $$$ are minimised.

First paragraph response... The loss of CLR aft (rudder lifts off ice) creates a situation where the CLR is now forward (front runners) and the mass is now aft = loss of directional stability. It's quite clear in the video with the way it flings around, just like an arrow would if shot backwards. I have no idea how an ice boat like that would keep the aft runner on the ice without weight aft, so perhaps it is a design fault to steering from the stern. Second paragraph response... Traditional boats are different, they have a lot more natural directional stability with a nice big aft rudder that rarely loses complete traction, but burying the bow can dramatically shift the CLR forward and induce a broach (loss of directional stability). Same thing happens on power boats so the rig dynamics are just an added complication. So it is a trade-off , move mass aft to keep bow out of water or keep mass forward and risk burying the bow. We are not dealing with traditional sailboats in the last couple of ACs, they are much more like slow speed planes, but with more complicated dynamics and a nearby free-surface. Continuin... The argument may be moot anyway. The crew mass is just under 15% of the total mass of the boats (from the rule, 1154/7819kg). It cannot get right to the back of the bus. So the risk of catastrophic instability may be negligible compared with weight forward. But the affect on the power required to maintain control (steady pitch) may be significant. There was a conference paper about moth ride-height control using an automatic active rudder gantry rather than the current flap systems, and it showed that the power requirements were greater (P=Fd/t), hence extra drag was induced.

That to me was a directional stability problem, too much weight aft AND not enough lateral resistance on the rudder so the tail wagged the dog. It isn't as simple as weight aft = good.

Maybe I shouldn't have used a plane analogy as stall recovery is a valid reason to keep weight forward, but that wasn't relevant to my argument. Directional stability is generally about keeping the mass forward of the centre of lateral resistance. Take an arrow or dart and try to shoot or throw it backwards, what happens? They are directionally unstable if the mass (tip) is aft of the centre of lateral resistance (fins). It isn't a simple problem to solve for a foiling boat, but if I was designing a foiling boat I would not be putting a signficant portion of the mass aft. This is both a pitch and yaw stability problem.

But is it faster to have more rudder downforce increasing righting moment or is it slower? $200million dollar question? For clarity, I think rudder downforce can be extremely efficient at producing righting moment. I'd be putting the weight as far forward as possible, but primarily for directional and pitch stability, weight aft is bad on planes.

JFK! If the feds aren't responsible for Australian borders then what are they responsible for? Is there sole domain to fund sports rorts? Do you need reminding of "Stop the boats!"? What a stupid fucking argument, only perpetuated by those who don't want to handle the responsibility of the task. Scomo and Dutton are pushing a wheelbarrow of shit and carry the stench to prove it. There's a god damn clue in the name of the public service Dutton started up, Australian Border Force. "Our mission is to protect Australia’s border and enable legitimate travel and trade" https://www.abf.gov.au/ Or does protecting Australia's border only extend to refugees and visa overstays? Fuck me sideways, unbelievable!

And actual CDC graph... https://covid.cdc.gov/covid-data-tracker/#trends_dailytrends

Definitely gunwale, someone else pointed out the guy on a ladder. View is looking forward and we can see the mast bulkhead at front of crew cockpit.

Graph stops 3 weeks ago. CDC linked dashboard below indicates the numbers are not zero now.

Gunwale?

Exactly my point and the example I was thinking of.

You, nor I, are experts in the field. You, nor I, are in a position of power that has to make (and stand-by) that decision. So I trust that the experts who do have the power to make that decision are making reasonable decisions based on the best information they have available. I also trust that they will adjust their decisions as time moves on. I also realise that there will be outbreaks of disagreement with the authorities, but sometimes they need to be called out and given a reality check. Remember, the clusterfuck that VIC is now in was caused by a few quarantined returned travellers who couldn't obey the rules, and a few security guards that couldn't enforce them. So it doesn't take many ignoring the reasonable protocols for COVID to get out of control. If the Feds want to make the decision to increase international arrivals, that's fine by me, as long as they negotiate how quarantine will be handled and do it effectively. It is the Feds legal responsibility, not the states, and if it goes pear-shaped then I expect the Federal decision makers to cop the blame, just as I will give credit for a good result. But honestly, from a publicity point of view, there's a lot of ways it could go wrong and unless they do it compassionately there's not much chance of public kudos. No wonder they tried to put the decision onto AP. I'm glad we're in some sort of agreement about the rest of the details.

If they're not in measurement, then they're not AC75s, hence surrogates. There are probably some mutually agreed rules regarding your second paragraph, or the other teams are just not interested in pursuing the infringements, for various reasons, for their own perceived benefit. If LR wanted to use motors instead of people and I was head of ETNZ (or any other team) I would not pursue an enforcement because one-day I might want to also use a motor for testing (two boats, COVID, etc). There's also the consideration that using motors is not the same as people power nor person weight and dynamic movements, so the value of testing in that config is debatable and might lead LR down the wrong path. Same with communication and the bits hanging off the foils. The teams will definitely pick their battles.