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Timmys_Trick_Turkey

Sports Boat on Foils

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Okay so theyve perfected foils on cats, and foils on the international moth class. How long now before we see a two or three handed moth style simplified sportsboat ?

The devaluation of the pre-foil moth hulls would be chump change compared to the devaluation of a non foiling sportsboat...

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These are preliminary sketches I did for a guy from Australia who wants a 30' self-righting sportsboat foiler:

--Detailed info on several versions here: http://www.boatdesign.net/forums/sailboats/foiling-keelboat-30-a-38395.html

post-30-0-79931300-1396737301_thumb.jpg

post-30-0-77934100-1396737496_thumb.jpg

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Doug, the hull looks nice but I'm trying to get my head around the rigs you draw for this and the foiling tri your building. Wouldn't making the sails low aspect decrease their efficiency on a foiling craft where the whole idea of foils is to be more efficient?

I also wonder if the tip losses/drag is greater having the main+jib end at the same spot.

 

Would it be worth looking at a tall rig similar to what we have on the A class then just downhauling the crap out of it to get rid of power? You already have a traveller there suitable to run a rig like that, then just whack a code zero on for light Air upwind and downwind.

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SK, I think there are lots of areas that could be improved-I'm comfortable with that rig but open to any other ideas. Keep in mind : to make something like this work(like on every design) there are compromises that have to be looked at in the light of the overall function of the boat. This is just preliminary.

 

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Doug,

that hull looks very much like a stealth ahead of its time.

At the Moth Internationals, the acceleration of the foiled moth is staggeringly quicker that the rest of the fleet, and the crash rates appear to have been substantially reduced. You have to wonder how much of that is skill, and how much is technological improvement.

 

Looking at Hydrocoptre, each wing end could turn down into a shallow but wide foil instead of a single deep one on the hull centreline. If the breeze picks up, you could fill a sliding water tank slung low between the two. The test comes in keeping it light enough to foil while maintaining the definition of monohull and making it trailable. If the Moths can do it, it should be a scaleable.

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no doug

 

for 'something like this to work' it would need to be built and paid for

 

stop wanking in this forum & go back whence you came

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That could be done but three problems arise:

1) drag from downforce,(the bi-foiler system contributes 40% of the total RM thru Veal Heel at minimum cost in drag).

2) extra wetted surface,

3) a problem could be created by bureaucrats protesting that such a configuration is a "multihull" configuration. That happened in the Moth class and the first foiler to win a major race was disqualified because of the two main foils hung off the outboard side of the racks.

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If it is a foiler it won't have any lead, and will be a dinghy, not a sportsboat.

 

You might want to revisit your preliminary sketches there doug, if that boat is 30' long your draft is somewhere around 10'. Not the most practical little trailer boat

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If it is a foiler it won't have any lead, and will be a dinghy, not a sportsboat.

 

You might want to revisit your preliminary sketches there doug, if that boat is 30' long your draft is somewhere around 10'. Not the most practical little trailer boat

 

Why not?

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If it is a foiler it won't have any lead, and will be a dinghy, not a sportsboat.

 

You might want to revisit your preliminary sketches there doug, if that boat is 30' long your draft is somewhere around 10'. Not the most practical little trailer boat

 

Why not?

Same reasons any other sports boat doesn't have a 10' draft. It is still a boat after all.

I am with gybset on this one, this thread is fluff.

Can I ask, after you pull the keel and rudder up to put that thing on the trailer what stops it from just falling over?

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Since when have sportsboats been practical ? Curve the wings down so they provide reserve buoyancy, or lift the boat out with the keel down using a crane. What stops a moth from falling over ? Its balls ? think like a moth sailor and grow a pair eh ?.

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Since when have sportsboats been practical ? Curve the wings down so they provide reserve buoyancy, or lift the boat out with the keel down using a crane. What stops a moth from falling over ? Its balls ? think like a moth sailor and grow a pair eh ?.

Moths are very different, you can carry them down to the water on your shoulder. And in answer to what stops a Moth from falling over the answer is nothing stops them. But they so small it doesn't matter but when a 30' boat starts falling over in the middle of a start line it creates a bit of a problem.

Some other issues are:

You motor out to the start line with the boat laying over at 20-30 degrees???

You finish the race and pull sails down, boat falls over.

Then you get a light wind race in the middle of a regatta....boat falls over.

 

Sports boats are practical for their purpose of sailing in nearly any inshore conditions and fast. A foil version would never to that.

Go and build one if you think it would be such a good thing, spend you money and prove me wrong, grow a pair! Bet you don't.

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Since when have sportsboats been practical ? Curve the wings down so they provide reserve buoyancy, or lift the boat out with the keel down using a crane. What stops a moth from falling over ? Its balls ? think like a moth sailor and grow a pair eh ?.

Moths are very different, you can carry them down to the water on your shoulder. And in answer to what stops a Moth from falling over the answer is nothing stops them. But they so small it doesn't matter but when a 30' boat starts falling over in the middle of a start line it creates a bit of a problem.

Some other issues are:

You motor out to the start line with the boat laying over at 20-30 degrees???

You finish the race and pull sails down, boat falls over.

Then you get a light wind race in the middle of a regatta....boat falls over.

 

Sports boats are practical for their purpose of sailing in nearly any inshore conditions and fast. A foil version would never to that.

Go and build one if you think it would be such a good thing, spend you money and prove me wrong, grow a pair! Bet you don't.

 

No it doesn't! Each version of the boat described at the link above is self-righting and carries lead ballast in a bulb to assure self-righting-that's the essence of a keelboat foiler.

In the picture below the Moth is being sailed with a little kid along for the ride,BUT that amount of weight could also be in a bulb at the bottom of the daggerboard:

And another example from the Moth worlds(penalty box productions) when Greta takes a ride: http://vimeo.com/77142951#at=0 6:04 in.

PS-this picture was sent to me with no credit-if anyone knows who took this picture please let me know so I can give them credit!

post-30-0-80111900-1396885861_thumb.jpg

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What's the attraction of trying to get a conservative lead-ballasted boat to foil?

You've got dinghies that fly - and folding multis that could fly if you want to throw enough money at them - and you don't have to deal with lead.

 

You can make a multi self-righting if you want as well.

 

I just don't get it.

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What's the attraction of trying to get a conservative lead-ballasted boat to foil?

 

You've got dinghies that fly - and folding multis that could fly if you want to throw enough money at them - and you don't have to deal with lead.

 

You can make a multi self-righting if you want as well.

 

I just don't get it.

 

Because it makes a self-righting foiler-self-righting is a required characteristic for many sportboats.

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Since when have sportsboats been practical ? Curve the wings down so they provide reserve buoyancy, or lift the boat out with the keel down using a crane. What stops a moth from falling over ? Its balls ? think like a moth sailor and grow a pair eh ?.

Moths are very different, you can carry them down to the water on your shoulder. And in answer to what stops a Moth from falling over the answer is nothing stops them. But they so small it doesn't matter but when a 30' boat starts falling over in the middle of a start line it creates a bit of a problem.

Some other issues are:

You motor out to the start line with the boat laying over at 20-30 degrees???

You finish the race and pull sails down, boat falls over.

Then you get a light wind race in the middle of a regatta....boat falls over.

 

Sports boats are practical for their purpose of sailing in nearly any inshore conditions and fast. A foil version would never to that.

Go and build one if you think it would be such a good thing, spend you money and prove me wrong, grow a pair! Bet you don't.

 

No it doesn't! Each version of the boat described at the link above is self-righting and carries lead ballast in a bulb to assure self-righting-that's the essence of a keelboat foiler.

In the picture below the Moth is being sailed with a little kid along for the ride,BUT that amount of weight could also be in a bulb at the bottom of the daggerboard:

And another example from the Moth worlds(penalty box productions) when Greta takes a ride: http://vimeo.com/77142951#at=0 6:04 in.

PS-this picture was sent to me with no credit-if anyone knows who took this picture please let me know so I can give them credit!

I am not sure why the picture of a Moth with a kid on board proves anything about how a sports boat could foil and be usable. It makes more sense than your sketches at the start of this thread though.

Build it and they will come

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Thats not just a kid passenger on that moth. Its a girlfriend of similar weight to the helmsman. And they are foiling, believe it or not.

 

You can build a shaw hull capable of being lifted by two guys (see hell yeah boatbuilders web page), so why not a foiling monohull ? Its not as though you had to sleep in it.

 

Now that the altitude technology has been resolved, and hull weights are getting right down, surely its just a question of scale.

 

Scale up a moth 300%, put two or three crew on it, and if necessary the third crews weight goes into a bulb instead.

Or scale down an AC challenger as shown in the video on the front page today.

 

Its not a bethwaite 2 person 18 foot skiff type mediocre solution. Thanks to Moth development, its a different and rapidly faster development direction, which 12 months ago wasnt technologically feasible.

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The Shaw 650s have been sailed without bulbs a few times for fun, and in the right conditions are semi-planing upwind, in full turbo mode (traps, big rig fully powered up) but not really lit up like a skiff (apparently Custard truck can come close which is a more extreme sportsboat with huge righting moment). Once you bolt 108kg of dead weight onto the bottom, that becomes impossible.

 

There is a double whammy, not only the extra weight, but also the drag created by the entire thing being heavier. now we are looking at also adding controllable foils on the bottom of the keel, with some sort of wand system..... the idea of scaling doesn't really work here if we make a moth 2X longer it is not going to be 2X faster, it is going to be the cubed squared issue that windsurfers and kites also face; however let's just assume that we did scale it up 2X we are talking about a 6.8m foot long 4.5m wide winged boat with 16sqm of sail that weighs <60kg. Now we are adding 100kg of dead weight into that plus another 50kg of safety equipment that is required in Cat 5 day Australia (engine, fuel, chain, anchor etc); so then the sail area increases, which causes load and weight increases, and around we go to needing more sail area and so on.

 

A light 6.5 sportsboat weighs around 150kg hull and decks with deckgear on no rig, which is lightish for that size boat, but a loooong way off where a Moth is. Yes you can make the boat 20 feet wide to bump the power up, but this is supposed to be a relatively easy boat to sail; if we wanted to sail ultra high performance, we'd buy moths, A class, 18 foot skiffs etc. With a moderate beam, it is for this same reason that no one is sailing a sportsboat upwind (one that is self righting) in planing mode. It's not a dinghy, it's a selfrighting stripped out daysailing keelboat.

 

Now while it is indeed true that foiling and planing are not the same thing, I suspect the threshold is not so far apart, with foiling at a lower threshold if the boat is light enough; sportsboats are far from light once you factor in the bulb.

 

Assuming that we would still want a sportsboat to be self righting, that means about 35% of the total weight of the empty boat is in the keel/bulb. It does nothing while the boat is sailed properly, (i.e. flat) but is there to make the boat self righting when something happens or goes wrong, and also to allow the boat to rate as a keelboat rather than a dinghy. no traps makes the righting moment an issue, now you can add big wings onto the boat as per Custard Truck or that basic sketch in this thread (ignoring that the boat in the sketch has no kite and would be likely to spend a fair chunk of time going down the mine with crew unable to get aft) but that is all adding rating points on and reducing the trailerable nature of the boat unless the wings are removable, and then that adds cost, weight and complexity.

 

I've spent time racing formula windsurfers including taking the GF and a dog out on the board; in the right conditions you can plane carting dead weight around, sure. But mostly, the lowest threshold for planing is with maximum power you can handle, maximum lateral area to power against in the water (deep fin with a wide tail) and as little deadweight as possible so every kg of weight is working and moving against the sail to generate power. I'm not convinced you would ever have enough power in the mid teen breeze range, to be able to power up the self righting boat enough to lift up on foils as the mothies and other boats do so it would be just dragging around foils for no reason a fair chunk of the time.

 

We have raced against a DSS boat here; it is not getting any benefit out of that foil upwind until powered up (i.e. around 12 knots+); I know the boats in Switzerland are a later generation, that would seem to be the more relevant use of foils for a sportsboat than attempting to try to get the entire boat to fly.

A sportsboat is a daysailing keelboat with a lot easier to sail characteristics than a lowrider moth or non self righting skiff. It is meant to be a simple boat to make go relatively fast while still self righting, capable of being raced alongside keelboats, able to be launched without needing to pull it over on its side to bolt on additional foils, and doesn't want to fall over when moored overnight. I have no idea of how to get the planing threshold upwind to 8 knots ( or any wind speed) on a sportsboat, so I have no idea how you would not only get the boat to plane, but to fly on the foils.

 

Regarding ratings, under SMS/IRC the forestay length and inability to adjust sail shape in that rough sketch make little sense; also there is no downwind sail nor a clear idea of how a kite would be flown off such a boat. Moving ballast, water tanks etc and any canting keel arrangement would make the boat totally uncompetitive in any existing rating rule (IRC, SMS, etc) as I am sure you are aware and also would add on additional complexity and challenges to sailing the thing; I am not sure you have ever raced a sportsboat - we are only club level sailors and with a crew of 4, there is stuff going on all the time and you are adding in on top of this foil control, water ballast pumping, power control, a rig no one has control over, an extremely unstable hull shape with massive beam.

 

Again, the DSS system seemed to tick off a lot of the boxes with about 5% of the effort you are proposing.

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well argued stevo. Sportsboats are starting to sound a bit like nascar, where the monohull shell becomes merely cosmetic. Now we just wait for someone with a lazy $100k to build the foiling moth on steroids. Kind of like what happened to the conventional trailer sailer scene when Stealthy arrived.

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I think it's probably best to not think of a foiling sportboat as a scaled up Moth -its not.

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This is the dumbest fucking thread in this whole forum. I was slowly gaining back some ability to entertain DL's posts until this piece of shit thread came along.

 

Further more, it's not the dudes "girlfriend" in that picture... It's a little kid you dolt.

 

You're all a bunch of fucking idiots. Go sailing and stop pretending you know what you're talking about.

 

You're all ruining a perfectly good sub-forum. Make this die!

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That you think there was just one such thread is kinda cute

 

 

This is the dumbest fucking thread in this whole forum. I was slowly gaining back some ability to entertain DL's posts until this piece of shit thread came along.

 

Further more, it's not the dudes "girlfriend" in that picture... It's a little kid you dolt.

 

You're all a bunch of fucking idiots. Go sailing and stop pretending you know what you're talking about.

 

You're all ruining a perfectly good sub-forum. Make this die!

.

......just another 'Lard-bait' thread

 

......keeps him busy while other threads continue unsoiled--don't tell him!

 

 

 

 

 

 

.......................................................oops! :unsure:

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What the fuck is that cantilevered floaty thingy on the top of the mast and square top jib? I guess if you had a back stay to yank on it perhaps it might work other than that i got to call bullshit on that rig. Cartoon design

it is part of the new high performance gaff rig DL has designed to go with his 30' foiler that flies 10' above the water. it is a new paradigm, get with the program!

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This is the dumbest fucking thread in this whole forum. I was slowly gaining back some ability to entertain DL's posts until this piece of shit thread came along.

 

Further more, it's not the dudes "girlfriend" in that picture... It's a little kid you dolt.

 

You're all a bunch of fucking idiots. Go sailing and stop pretending you know what you're talking about.

 

You're all ruining a perfectly good sub-forum. Make this die!

fully agree

 

Lo rd has tried this on periodically for a decade to spread his virus across all avail forums

 

fuck off trick turkey baiting ( if it could be done it would have been done) and fuck off Doug

  • the 'super size Moth' and all other Lor d derivitives have not the live ballast 4 times the boat displacement trimming fast & reactively (fore/aft/athwartshps) to make it do-able
  • No examples of lead foilers afaik

it does not exist

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well argued stevo. Sportsboats are starting to sound a bit like nascar, where the monohull shell becomes merely cosmetic. Now we just wait for someone with a lazy $100k to build the foiling moth on steroids. Kind of like what happened to the conventional trailer sailer scene when Stealthy arrived.

I'd think you would be looking at double that, I have a mate in Brisbane that said Raptor cost well North of $100k so add in the extra cost of foils and also the design and development fees you need to have a fair bit more than that in the budget.

Doug Lord linked a thread where he said he had someone with the money and then nothing happened. i think it was all a story to try to pass off a few sketches on a napkin as designs.

I think sports boat are becoming less like Nascar though, In all reality there isn't that many boats not finishing regatta due to damage these days, weather that is because rigs are getting better or the fleet as a whole is getting better, I'm not sure. But it is good

Yes and that rig, What a heap of shit, There is no way anyone who came up with that heap, has the brain power to design a foiling boat

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.

 

...umm,,why not make a little singlehander so you don't need lead....you could have big hiking wings instead

 

................if you weren't such a sloth,,I'd suggest yer call it a moth! :)

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... where the monohull shell becomes merely cosmetic.

No

 

that argument is based if it were a foiler, a jump to a fictitious conclusion

 

go down the waterfront and have a look around, they are in the water not folling

 

aside from the subject of SBs, can ANYONE post a link or pic of a leaden, self-righting Foiler

 

you are trolling for Do ug

 

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self-righting means what?

 

sinkable?

 

I like you're thinking .Once on the bottom, it sits mast pointing toward the surface; clever.

 

Mex

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