Proa - Cat Hybrid?
Interesting… I’m not a proponent of lifting/flying foils for any boats but the most committed racing machines. Here’s why…
Lifting foils by their very nature are very fiddly and require precious attention in order to extract the best they have to offer. I have not seen any lifting/flying foil setup that is a functional, set it and forget it, operation. They all need constant attention of some sort in order to keep the boat functioning at its best and that’s not practical, or possible, for cruising, or recreational boats. It’s either the constant attention thing, or, it’s about not being able to operate in a wide variety of conditions. Either way, it’s incredibly frustrating to be outside the performance envelope when your expectations tell you otherwise.
Flying foils are potentially, maintenance whores. There’s all kinds of moving bits that need to be looked after in order to address angle of attack, trim to optimum speed envelope and minimize drag profiles in diverse conditions. These bits are susceptible to breakage/wear and tear and then you are right back to straight foils with no extraneous moving parts in order to function at lower wind speeds, or make way.
Lifting foils, with their horizontal, or near horizontal, surfaces, are seriously prone to the collection of all sorts of crap in the water. They can not be easily cleaned, as one would do for a standard dagger board, for example, by simply lifting the appendage, clearing the detritus and getting back to the program. No, instead, one would have to stop the boat, get themselves, or some kind of unique “cleaning tool” under the hull and remove the crap by hand… only then can you resume flying. Sail in an area of regular weed conditions… forget foiling as a practice. You’ll spend more time getting pissed off about the constant fluctuation than actually getting it on and enjoying it.
Cost… No matter what the foilistas say about how much like producing a standard appendage it is to make a curved, L, or J foil, just try to get some Bubba to knock-out a board for you at a boat yard in, oh, let’s say…. Mobile, Alabama, and see what you get for a costly shaping and trunk fitting session while you are not out there, sailing your fanny off with a big smile. It would be even worse if you try to get that same board built in Zanzibar, while on a world cruise.
Additionally, the cost for all the fiddly adjustment bits can really spin the cash clock and those are not some standard items, either. More like custom everything with prices to go with the custom moniker.
Lastly, are you really ready to light it up and cook along at 30 knots+? Oh, I know that your “let’s go for it” devil is saying, “oh, sure, we can handle 30 knots, no sweat”... but your little self preservation angel ought to be telling you that you are not Thomas Coville, or Francis Joyon and you should be cooling your jets. Stuff happens really fast at thirty knots+ and it is not a playground for the poorly trained. I’ve been aboard, steering the maxi-tri Sodeb’O at 26 knots in an 18 knot breeze when she was, really, just loafing along. I can only tell you that what you just saw as the horizon, starts to approach your near field vision in a real hurry aboard a boat that big and that powerful, moving at those kinds of speeds. It’s even more overwhelming when you realize that Coville has routinely had that boat cooking along in the mid 40 knot region while blasting across the Southern Ocean on the leading edge of a low pressure zone. It’s daunting.
by the time they are built sturdily enough for high speed in big waves and hitting whales, logs or semi submerged containers, the additional weight and drag would render them counter productive in almost all conditions.
This is true of ANY multihull out there today… I would love to see the latest breed of AC72 hitting a semi-submerged log at 30 knots, or any modern production-boat hitting a log at 10 knots…
I don’t think any fin-keel or modern rudder is stronger than a steel/aluminium/titanium/Monel - tunnel-foil. The actual foil is probably much stronger then the structures inside the hull that is holding it. I have a couple of ideas on very simple self-adjusting setups for tunnel-foils. We have just begun using foils, and i think that every current usage of foils are very primitive. Give them another 100 years of development and i think the flying proa is really flying 3 feet of the surface, at speeds we barely believe possible today. With jet-assisted supercavitating foils and advanced computers controling everything I believe we will be sailing at 80 - 100 knots or so.
It is only 50 years ago we in the western part of the world started using multihulls. An AC72 is quite a development from a Piver trimaran. Give the foils the same amount of time to evolve.
Cheers,
Johannes
I think that it would be good to know that we are not at the beginning of foil use for boats. Hydrofoils have been in use/development for well over a hundred years already and it is not an immature science. During this time, there have been a number of “birth of the hydrofoil” episodes and all of them have eventually lost favor due to inherent problems associated when compared with other methodologies.
As our global culture continues on at a breakneck speed to apparently ruin the oceans with the sheer amount of crap we dump into the seas every day, we are going to be seeing more floating junk in the water and not less. This floating junk is the Achilles heel of the foil efforts. It is a very big and very dangerous problem for anyone who thinks that they are going to be blasting around the planet at 50+ knots, no matter what kind of boat they wish to utilize.
I wish you guys the best in your pursuits, but I am not focusing my design efforts on a process that has already shown itself to have too many problems for it to be pragmatic in application. Instead, I would suggest that the function of a very modest foil assist paradigm is a far better approach with many of the issues of full flying foil setups being eliminated as a function of the simpler design aesthetic.
The single biggest question would be… “Just how fast do you think you can reasonably go in a boat without it becoming a problem unto itself?”
Chris,
Well said….spot on.
Rob
As our global culture continues on at a breakneck speed to apparently ruin the oceans with the sheer amount of crap we dump into the seas every day, we are going to be seeing more floating junk in the water and not less. This floating junk is the Achilles heel of the foil efforts. It is a very big and very dangerous problem for anyone who thinks that they are going to be blasting around the planet at 50+ knots, no matter what kind of boat they wish to utilize.
This is sadly all to true…
Not only for high speed sailing, but for any kind of cruising.
Im sad that we no longer can experience the world like the Polynesians did 500 years ago, but at the same time I’m very happy there is epoxy and plywood, internet and cheap computing power.
The “easy foiling” is within this thread, where I think it is a much more viable option then 4 surfboards connected with several crossbeams. I believe hydrofoils is overly complex today, and could be made much more simple, stronger and cheaper. I’m very impressed by Vestas Sailrocket and L’Hydroptere, and I think they are showing us the future in high speed sailing.
I don’t build or develop any hydrofoilers, even if I have a strong interest in almost every aspect of fast sailing.
I have several ideas I would like to develop, test and build, but I have to concentrate my efforts on the opposite side of the scale from Vestas sailrocket.
Cheers,
Johannes
Enjoying the debate, and I think you are all right. The issue is not the technology but that we all have different approach directions. I have noticed over the past few weeks, on many different posting, the debate is not the subject but people’s proa requirements. Just for fun I drew up a list, far from exhaustive, of people’s main interest in proas
Pottering
Social
Thrill seeking
Tinkering - for the engineering challenge
Day sail expeditioning
Weekend expeditioning
Coastal cruising
Inshore cruising
Offshore cruising
Offshore racing
Speed sailing
So if you are a thrill seeker your passion from foils will be different from someone who wants to go on a weekend expedition.
Just an observation
I personally believe that proas do represent the most efficient platform for foils. However one thing that I don’t think that has be mentioned and one of the reasons I don’t work on foiling proa’s is shunting. I don’t know about bigger platforms but international moths remain foiling through the tack. I would love to hear if any you that think proas can overcome having to come off foils to shunt
TINK
I personally believe that proas do represent the most efficient platform for foils. However one thing that I don’t think that has be mentioned and one of the reasons I don’t work on foiling proa’s is shunting. I don’t know about bigger platforms but international moths remain foiling through the tack. I would love to hear if any you that think proas can overcome having to come off foils to shunt
TINK
Darn Tink, you should know that tossing a gauntlet down in this crowd is a good way to waste some time 😉
Don’t think I’ll take the bait at the moment, agree that proas are probably the most efficient platform for foils but by extension they are pretty darn good in a lot of other categories. For example, foils are often mentioned as shining for ride quality at high speed vrs mundane displacement hulls, but a long lightly loaded proa is the “pinnacle” of displacement ride quality, why bother with foils and the attendant headaches that Chris O quite correctly points out?
For future reference what exactly constitutes “overcome having to come off foils to shunt”?
My personal scale of interest 1-10 for your very nice list
10 Pottering
2 Social
0 Thrill seeking
10 Tinkering - for the engineering challenge
8 Day sail expeditioning
10 Weekend expeditioning
8 Coastal cruising
5 Inshore cruising
0 Offshore cruising
0 Offshore racing
0 Speed sailing
Cheers,
Skip
Darn Tink, you should know that tossing a gauntlet down in this crowd is a good way to waste some time 😉
That was the intention
For future reference what exactly constitutes “overcome having to come off foils to shunt”?
I was being purposefully vague, I did not want be limit thoughts. But how about any inefficiencies of shunting being a minor inconvenience compared to other advantages.
On another point (Chris O issue) depending how the foils are arranged they could be set cleaning, weed would be washed off during the shunt with bi-directional foils.
Tink
For the record, my personal scale of interest 1-10:
3 Pottering
2 Social
1 Thrill seeking
4 Tinkering - for the engineering challenge
10 Day sail expeditioning
10 Weekend expeditioning
10 Coastal cruising
10 Inshore cruising
7 Offshore cruising
2 Offshore racing
0 Speed sailing
Plus, I would rather get to Hobart for shopping / business in 2 hours by boat instead of 1 hour by car.
Skip is right, proas are pretty darn good in almost all categories. A long lightly loaded proa is the “pinnacle” of displacement ride quality, why bother with foils?
But why bother with displacement sailing? Proas can get up on the plane….Frank Bethwaite devised a formula/ ratio called Sail Carrying Power: righting moment divided by heeling arm and the result divided by displacement and then expressed as a percentage. He reckoned that you needed 30% plus to plane consistently to windward. It is not difficult for a proa to achieve that. My current design is about 38%. So I won’t be foiling, I hope to plane.
Rob
Speed’s kind of a relative thing. For me quick is good, blinding white knuckle skipping from wave crest to wave crest- not so much. For my next proa 12-14 mph easily achieved a real pleasure; the ability to slide along on the lightest breath of wind, a thing of joy.
I’ll leave the faster, faster speed thing to the young and restless, I’m neither. any more.
cheers,
Skip
This has become a cool thread, lots of insightful posts. I love hydrofoils too, but for my personal interests, they don’t much fit unless its a Bruce foil or some such. Rob said:
So I won’t be foiling, I hope to plane.
I’ve been noodling a planing proa as well. Sort of a big wake board with outrigger - with some accommodations.
Here’s my version of your list, TINK:
10 Pottering
5 Social
5 Thrill seeking (to me, visiting new places by sail is a thrill)
7 Tinkering - for the engineering challenge
8 Day sail expeditioning
10 Weekend expeditioning
8 Coastal cruising
8 Inshore cruising
4 Offshore cruising
0 Offshore racing
0 Speed sailing
I like your list Tink.
Here is my version:
0 Pottering
1 Social
5 Thrill seeking
10 Tinkering - for the engineering challenge
2 Day sail expeditioning
2 Weekend expeditioning
3 Coastal cruising
4 Inshore cruising
10 Offshore cruising
0 Offshore racing
5 Speed sailing
Johannes
For my next proa 12-14 mph easily achieved a real pleasure; the ability to slide along on the lightest breath of wind, a thing of joy.
But Skip, at that speed in a small/medium sized proa, you could already be planing…...If you have ever helmed a boat planing upwind, it is indeed an even bigger thing of joy. The helm is so light and responsive.
The challenge for me is not the ultimate speed achievable whilst planing, it is to get the boat up planing in as light a wind as possible…...which is something which inherently, foils can’t do as well.
Why would you want to do 30 knots plus in big confused waves during a squally moonless night in any kind of boat unless you love playing Russian Roulette??
Rob
But Skip, at that speed in a small/medium sized proa, you could already be planing…...If you have ever helmed a boat planing upwind, it is indeed an even bigger thing of joy. The helm is so light and responsive.
Planing in a hull with a displacement/length ratio less than 30 is subject to a little interpretation. P52 would easily reach that 12-14 mph sweet spot in a variety of conditions and it was interesting to watch the (absence of) wake behind the hull. Same craft at 20 mph was a completely, in a different universe, kind of experience, my most lucid thought was ” this isn’t the kind of thing you want to do in a boat built out of $10 plywood”,
For me, the beauty, the joy comes from getting the mostest from the leastest. Pacific proas are an almost perfect example of this beauty. Quick, simple, low stress; it’s possible to build craft with the simplest of materials that can (almost) run with the highest tech stuff around. Toss in a little low stretch fiber and maybe some carbon and you have the capability to be banned or at least ostracized in some circles though that’s not part of my interest.
What does interest me is that there is a lot of unexplored territory in getting more from less. Ease of handling, ghosting conditions, adaptability to varying conditions, I’ll keep at it.
One last thing, as much as I enjoy this stuff I doubt it will ever quite match the bang for a buck of a double blade paddle.
cheers,
Skip