GC 32 super cat

Sail Rocket

I disagree, Hump-and so does Paul Larsen. The foil develops lift downwards after starting off with vertical lift. But foil lift is lift whether up or down. The foil lift on SailRocket is critical at speed since it holds the boat to the water-w/o foil lift the boat would fly once. Boats like the Trifoiler, Rave and Osprey rely on downforce for righting moment-and there is no doubt they are foilers. There should be no doubt that Sail Rocket is a foiler as well..... with "planing assist".....

Heres what Larsen submitted about his "boat" with the boat description in bold:

The WSSR Council announces the the establishment of a new World Record.
Record: Outright World and World “B” Division Sailing Speed Record
Venue: Walvis Bay. Namibia.
Name: Paul Larsen. AUS.
Equipment: Vestas SailRocket 2. Inclined rig Hydrofoil Proa.
Date: 24th November 2012. @ 13.32 hrs
Course length: 500 metres
Current: Nil
Elapsed time: 14.85 secs
Speed: 65.45 kts

Comments: Previous Outright and “B” Division Record: 2012. Vestas SailRocket 2. Paul Larsen AUS. Walvis Bay NAM. 59.37 kts

John Reed
Secretary to the WSSR Council

65.45kts (75.27mph)

 

There you go Hump. Doug has the gen.

 

I've seen the WSSRC definition from Paul Larsen before, but respectfully disagree with it. I have an almost identical boat, so I am very familiar with the operation. Boat like the Trifoiler, Rave and Osprey all use foils as their primary lifting force producers, and are thus without doubt foilers, but would they still be if there were no lifting foils, just downforce-creating foils to windward?

Bear in mind that Sailrocket does not generate righting moment with the foil, as there is no need, the foil just directly resists sail force. This is identical to the daggerboard on a skiff that is sailed inclined to windward. Are they foilers? If so, then yes, Sailrocket is also a foiler, as is every other sailing craft. My understanding of a foiler is when the foil forces are not substantially in the same direction as the sail forces, and that the foils substantially support the boats weight.

Also, I am intrigued as to how the Sailrocket foil starts off with vertical lift? When starting the boat makes a lot of leeway, and the foil is inclined, so it can only generate downforce unless they change the inclination during the start up phase, which I don't think they do.

As I said, it's just being pedantic, but it would be nice to have a universally understood definition of terms like "foiler", "foiling", etc.

 

Agreed, they're all foilers; any boat type using vertical, angled, down, up, sideways, positive or negative lift, all foilers imo.
But sideways carryng ballast, conventional keelboat, no. Although of course, they do use foils.

 

The Glide foiling kit, a beautifully designed product created by two extremely smart people to be as cheap as practical foils can be, is about $6,000. AMAC's Wasp may cost $15,000, if he manages to bring it in cheaper than a Laser plus a Glide kit (which seems pretty difficult given that the creators of the Laser and the Glide kit are very smart, just like Amac).

Stats show that "most people" in Australia are in households with $20,000 per annum left after rent and taxes for food, clothing, travel to work, childcare expenses, school costs and fees. On average "most people" find $500 to spend on sporting equipment in this extremely affluent sports-mad nation.

So will "most people" really find it easy to spend 30 years normal sports equipment spending on one piece of sports gear, or 12 years normal spending for foils to go under the Laser they may have?

Yes, sailing does attract affluent people, but those figures may illustrate just how much difference there is between those who assume that "most people" can just waltz out and buy a foiler, and the reality.

Cost is the #1 barrier to taking up sailing in Australia, and the fourth biggest reason to drop out of the sport. Gemba report, 2012) Cost is particularly important for people with kids according to the Gemba report, so even if kids are excited by foilers most of them are out of luck because most parents can't afford one.

Sure, leading edge gear has never been all that cheap (although at times it has been vastly more economical than a M2 or GC32) but there is a reason that the sports that are booming are ones where you can buy "leading edge" gear for a fraction of the cost of a foiling dinghy. And perhaps more importantly, I don't know of any time where the promoters of extremely expensive sailing equipment has hyped it as "THE future" in a way that says bluntly that those who cannot afford such gear have no place in the future of the sport.

On top of that, an enormous number of people sail very keenly on waterways that are too tight for foilers, and especially foiling cats. Take Middle Harbour in Sydney, for example - in many places it's less than 500 metres wide over the length of an entire racecourse. Fleets of foiling cats would not fit. So according to the "foiling cats are the future" hype, the place that helped to launch the sailing and designing careers of Julian and Frank Bethwaite, Ian Ward, and Iain Murray will not be part of the future of the sport.

In fact there is no room for big cat fleets to rig and launch just about anywhere on Sydney Harbour, with maybe four exceptions. So apparently just about all of Sydney Harbour will also be left out of 'the future of the sport', as will the majority of English small-boat racing centres, most small-boat centres in Germany and even in places like South Africa.

Is this vision of the sport, many of the places that currently have thriving fleets will become sailing ghost towns, locked out of the sport that will evolve. Is this really a great vision?

 

1- I didn't say that kiters were faster than Sailrocket. However, if you want to race Sailrocket around a normal course against a kite, or even against a Zephyr, go ahead.

2- So all the kids in Auckland and the Christchurch estuary whose parents don't have a spare $25000 per kid are now excluded from the future of sail racing? Is that a good thing?

3 - In what popular participant sport does normal gear cost as much as a foiler? None that I know of. In contrast, there are many extremely popular sports in which the emphasis, even at the top level, is on gear that is economical and easy to use.

As an example, SPARC shows that the "equipment sport" Kiwi males of earning age (ie those who may be able to afford a foiler) most want to get into is cycling, in which the pros use the same sort of kit that you can buy in your local shop for anywhere from the price of two Laser sails up to the price of a Laser and trailer, and ride to work or the races. That is the recipe for a healthy sport, and sailing's failure to follow that recipe is surely a major reason for its collapsing popularity even in places like NZ. People like Spencer and Holt - the ones who created sailing as an accessible sport - must be spinning in their graves at 10000 rpm as they see it returning to a sport for the rich, as it was in the 1930s.

Sure, foilers are great....never said they weren't. But the emphasis on them as the only future of the sport, or even of the performance side of the sport, could be extremely bad for the sport.

 

SailRocket

video with Paul Larsen describing a little about the foil at 2:15 in: Listen for the words "it's self-regulating". Here is a pretty good SailRocket thread: http://www.boatdesign.net/forums/multihulls/sailrocket-2-set-launch-36825.html I've gone thru the first four pages yesterday and today and haven't found the description where the foil lifts vertically initially. But Pauls "self-regulating" comment is important. I'll continue to look as I have time-if I remember correctly, there is an illustration that makes mention of the way lift changes on the foil as it speeds up.

https://vimeo.com/20780602

 

I've seen that vid before, and I think you may have misinterpreted what Paul is saying. The foil pivots to provide a stable resistance to the sail force to correct roll, but this pivoting means the flat upper section can "feel" the water surface but won't provide lift to the boat as if it lifts it will just pivot. The rear planing surface flies only because of the relative position of the pivot compared to the height of the planing surface.

You should also bear in mind that this is not the foil used for the record-breaking runs, though that does not change the principle, just the equilibrium position.

 

When I have time, I'll try to find the info on that thread where it is clear that I haven't misinterpreted what Paul says. Went thru all this in great detail a while ago......

 

I think like anything it stays expensive while poeple are trying to hold and maintain there technological edge by manufacturing it themselves. If it gets truly popular then to keep up it has to be made in China where by the tech then slips out the back door to everyone and becomes cheap.


Barry

 

CT, you probably consider me extreme but the same applies to you with your arguments/responses.
But I'm in agreement with your socialistic emphasis in making sailing available to all. However narrowing down to the present and future foilers taking over high end RACING, there is absolutely no doubt that that is going to occur, already has occurrred.
But you miss a point or two when it comes to working class approaches and innovation; in fact all the modern developments have originally come from average income, but talented peoples' original thinking years, even decades before the sailing populace accepted changes. Just look at Australian and NZ small boat history.
Also, although I'm a back yard builder and tinkerer, to actually build decent foils that perform and last is not difficult, nor horrendously expensive, meaning todays price of uni-directional carbon is actually low. You just have to put in the time building yourself. Our Southern Antipodean ancestors/pioneers achieved success by side stepping elaborate and expensive manufacturing. This is still possible.

 

=======================
Found part of it here: http://www.sailrocket.com/node/292

"The back of the boat will lift onto the curve of the foil at around 25 knots. The leeward float will begin to fly clear of the water over 50 knots. Only the main foil, the rudder and the ‘step’ of the forward float will be in the water at high speed."

 

Again, I think that is a misinterpretation. The back of the boat lifts as the tension between the sail and the foil pulls the back planing surface up, but the foil is not providing the lift, the sail is.

 

Hump, that very special sail ... is an air foil?

 

Absolutely!!

Interestingly, there are some significant advantages to lifting using an aerofoil, which have applicability to offshore and inshore boats, but aren't really being exploited at the minute. I've a feeling they will be soon, though, as when using hydrofoils the speed increase makes aerofoils more effective.