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Gunboat G4 Foiler


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#1 Doug Lord

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Posted 12 May 2014 - 01:58 PM

The first full foiler(as far as I know) from Gunboat:   http://www.gunboat.c...ries/gunboat-g4   You know it's a Revolution now!

Could be a good race between this and Morelli and Melvins California 45: http://forums.sailin...2&hl=california

 

Renders of Gunboat G4:

Attached Files



#2 Just a Skosh

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Posted 12 May 2014 - 02:04 PM

Doesn't sound like they're planning on having it fly, more to just keep it from nose diving.   



#3 Doug Lord

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Posted 12 May 2014 - 02:07 PM

Doesn't seem like they'd use UptiP foils for just foil assist-the uptip foils have an integral altitude control system. Theres another render on the page with "C" foils which could be ideal for foil assist.



#4 EarthBM

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Posted 12 May 2014 - 03:43 PM

If I were to risk my money on a revolutionary new project like this I would first try some proof of concept prototyping, with something of a realisticly similar displacement and sailplan. Like add foils to an old Concer or even Sig 45.

#5 ProaSailor

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Posted 12 May 2014 - 06:55 PM

Super cool! Thanks Doug. YouTube video is dated Oct 7, 2013 - what took so long to get the news here?

#6 Doug Lord

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Posted 12 May 2014 - 07:05 PM

Super cool! Thanks Doug. YouTube video is dated Oct 7, 2013 - what took so long to get the news here?

 

Thanks-did you notice the difference between the foils on the renders I posted and the foils in the video? They would not have caught my eye-"just" foil assist. But the UptiP foils-now thats a cat of a different color! Thanks to Peter Huston on the "trickle down " thread this morning..... 



#7 bloodshot

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Posted 12 May 2014 - 07:33 PM

no way in hell that thing gets out of the water.



#8 TheFlash

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Posted 12 May 2014 - 07:39 PM

Marketing types know to sell the customer what they want.  Remember those mid-80 cruisers with Am Cup keel winglets?



#9 gregj1

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Posted 13 May 2014 - 03:04 PM

actually it was here when it was introduced.  If you read the narrative the idea isn't foiling it's being able to push hard off wind without stuffing a bow and, you don't have to tack or gybe the boards.



#10 BigSquid

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Posted 13 May 2014 - 07:22 PM

2. C-FOIL DAGGERBOARDS: When you achieve a 2.4 ton displacement, lifting foils make a significant contribution to performance. The C-foil daggerboards provide lift, reduce drag, and keep things safe when pressed downwind. Thanks to their symmetric shape, both foils can be left down. There is no need to raise or lower the boards when tacking or jibing.



#11 soma

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Posted 13 May 2014 - 07:48 PM

Doug's right, there's a full foiling version. Pretty cool boat. Not sure how many have sold, but definitely not vapor. Tooling has been made.

#12 bloodshot

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Posted 13 May 2014 - 07:50 PM

full foiling even with a fully tricked-out salon and berths?



#13 Airwick

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Posted 13 May 2014 - 07:57 PM

2. C-FOIL DAGGERBOARDS: When you achieve a 2.4 ton displacement, lifting foils make a significant contribution to performance. The C-foil daggerboards provide lift, reduce drag, and keep things safe when pressed downwind. Thanks to their symmetric shape, both foils can be left down. There is no need to raise or lower the boards when tacking or jibing.

 

But the renderings aren't C-foils any more but the sharp (and trendy) J-foil shape. These don't seem to make much sense if you are not trying to fly though...

 

Is it a change of plan and will they try to make it fly or is it just for looks? I don't see why it couldn't fly but it would probably take a fair bit of wind.

 

Wait and see I guess...



#14 BigSquid

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Posted 13 May 2014 - 08:20 PM

It will be the first offshore fully foiling boat unless you think of Hydroptere as an ocean going boat.  Pretty surprising proposition given their current clients and products.



#15 Trov„o

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Posted 13 May 2014 - 08:25 PM

It will be the first offshore fully foiling boat unless you think of Hydroptere as an ocean going boat.  Pretty surprising proposition given their current clients and products.

 

imho it won't be really an offshore boat -more like coastal.



#16 Doug Lord

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Posted 13 May 2014 - 08:54 PM

Don't forget the M&M California 45 foiler-more of a daysailer and less a cruiser than this boat. They probably wouldn't have done new renders showing the UptiP foils if they didn't intend to fully fly. The "C's" would have been fine for foil assist......



#17 EarthBM

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Posted 13 May 2014 - 10:13 PM

I say these J foil renderings are just to excite the fantasies of potential buyers...

AC45s had 1.4ton displacement and needed a wing and 5 pros to fly.

Both Cali 45 and G4 will be pushing reality to get below twice that displacement, with soft sails and crewed by 2-3 mere mortals.

#18 Doug Lord

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Posted 13 May 2014 - 10:54 PM

I say these J foil renderings are just to excite the fantasies of potential buyers...

AC45s had 1.4ton displacement and needed a wing and 5 pros to fly.

Both Cali 45 and G4 will be pushing reality to get below twice that displacement, with soft sails and crewed by 2-3 mere mortals.

 

Remember this when you're tempted to think like that:

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#19 soma

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Posted 14 May 2014 - 11:48 AM

I say these J foil renderings are just to excite the fantasies of potential buyers...

AC45s had 1.4ton displacement and needed a wing and 5 pros to fly.

Both Cali 45 and G4 will be pushing reality to get below twice that displacement, with soft sails and crewed by 2-3 mere mortals.


I tend to agree. If you look at the GC 32 up tip boards they're huge. To get stable flight it looks like they need a huge lifting surface. Quadruple the displacement and simplify further for "cruise-ability" and I think you have a very difficult problem to solve. PJ is a clever guy though and he's got some clever people backing him up.

#20 unShirley

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Posted 14 May 2014 - 01:31 PM

It will be the first offshore fully foiling boat unless you think of Hydroptere as an ocean going boat.  Pretty surprising proposition given their current clients and products.

 

wrong:

https://www.youtube....h?v=1cYXxZiL4B8



#21 BigSquid

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Posted 14 May 2014 - 04:09 PM

I said fully foiling not full of foils.
In videos that haven't had the playback speed doubled it is clear that the boat is not fast even during the moments it gets all its hulls out of the water momentarily:
If the foils get so large that their induced drag approaches or exceeds the drag of the hull(s) they are lifting then what's the point of foiling?
IMHO, the renders of the G4 are already looking too big and draggy.

#22 floater

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Posted 14 May 2014 - 05:39 PM

PJ publicly derided M&M for suggesting TNZ foils on a gunboat - looks like he's come around on that idea.

#23 TheFlash

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Posted 14 May 2014 - 06:29 PM

A good biz guy will give his customers what they want, of course, assuming it won't kill them.



#24 Reht

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Posted 14 May 2014 - 06:57 PM

From the article that was posted out front it sounds like c-foils are still going to be the main plan. They should help a great deal making cruising more comfortable and faster. The fully foiling option will be just that, an option if there is enough interest.

 

How cool would it be to go cruising around in the Carib and doing your island hops full up on foils (heck, might even make navigation easier if you can just go over the reefs rather than around them).



#25 Chris O

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Posted 14 May 2014 - 07:35 PM

How cool would it be to go cruising around in the Carib and doing your island hops full up on foils (heck, might even make navigation easier if you can just go over the reefs rather than around them).

 

 

What a dumbass... they'll be jumping over the reef structures on foils and not a scratch on the Gunboat. Just ask DL. He's jumped a Gunboat on foils before and he'll tell you all about it.

 

.



#26 STYACHT

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Posted 14 May 2014 - 07:37 PM

Hi all,

 

the discussion above of (take your pick) really full foiling, area of foils, shape of foils does not, at first glance, make any mention of either TWS or boat speed.  An AC45 can foil in not a lot of TWS and has speed through the water considerably better than that windspeed when it does.  It can do this at a pretty wide range of angles too, because it is lighter by far than the G4 and the rig (wing) are prepped for it.  I doubt the GC32 has as broad a foiling range as the AC45, but that is not the point.

 

It is going to take more TWS and more (pre-foiling) boat speed, like a fair bit more, to make the leap on the G4.  That is a fact not lost on anybody involved.  Nor is the reality that foiling will be a max speed TWA 110-130 scenario as opposed to all TWA. As Rudo mentioned, the first thing to do is to work on the area of transition, where we are generating 1/3 or more of the boats weight as hydrodynamic lift in place from hydrostatic displacement.  We are pretty confident that within the envelope of operation it will be worth it shed all of that wetted surface by producing lift and drag at the foils.  So, we are getting the boat and the foil package ready for exactly that.  But we will walk before we run and fly.



#27 Reht

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Posted 14 May 2014 - 07:38 PM

How cool would it be to go cruising around in the Carib and doing your island hops full up on foils (heck, might even make navigation easier if you can just go over the reefs rather than around them).

 

 

What a dumbass... they'll be jumping over the reef structures on foils and not a scratch on the Gunboat. Just ask DL. He's jumped a Gunboat on foils before and he'll tell you all about it.

 

.

Now I'm not sure if you picked up the sarcasm I intended in that comment. Probably not.



#28 Chris O

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Posted 14 May 2014 - 07:40 PM

Or mine.



#29 unShirley

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Posted 14 May 2014 - 09:44 PM

Big Squid,

 

I saw Williwaw in action in person.  It was very fast, especially by 1970s standards.  Keiper was a pioneer.   



#30 Lat21

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Posted 15 May 2014 - 12:36 AM

STYACHT, thanks for the intelligent contribution to the discussion.

 

I know the polars link on the front page shows the C-Foils but the polar chart looks a little wacky. Are the max speeds off the wind really that deep? I could see max vmg being that deep, but would expect boat speeds to be higher in the +-120 range. 



#31 Doug Lord

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Posted 15 May 2014 - 01:00 AM

correction:

David Keiper was well respected and his boat foiled very well for the technology available then. The technology available now with UptiP foils is way superior to what Keiper used and is certainly capable of being used in an application like the G4.

Gunboat has a rep for quality and performance and they sure as hell wouldn't draw pretty pictures of UptiP foils just for the fun of it.

 

PS There is more to the use of foils than just speed! Foils can improve the ride and improve handling in rough conditions. And flying at any speed is just plain fun.


 



#32 TheFlash

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Posted 15 May 2014 - 02:22 AM

who said it was just a pretty picture?



#33 sailingkid

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Posted 15 May 2014 - 02:51 AM

correction:
David Keiper was well respected and his boat foiled very well for the technology available then. The technology available now with UptiP foils is way superior to what Keiper used and is certainly capable of being used in an application like the G4.
Gunboat has a rep for quality and performance and they sure as hell wouldn't draw pretty pictures of UptiP foils just for the fun of it.
 
PS There is more to the use of foils than just speed! Foils can improve the ride and improve handling in rough conditions. And flying at any speed is just plain fun.

 

Doug, I've gotta ask, where did the Capitol P on uptip come from...surely acute Ls is a more descriptive way of putting it!

#34 macca

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Posted 15 May 2014 - 03:42 AM

Hi all,

 

the discussion above of (take your pick) really full foiling, area of foils, shape of foils does not, at first glance, make any mention of either TWS or boat speed.  An AC45 can foil in not a lot of TWS and has speed through the water considerably better than that windspeed when it does.  It can do this at a pretty wide range of angles too, because it is lighter by far than the G4 and the rig (wing) are prepped for it.  I doubt the GC32 has as broad a foiling range as the AC45, but that is not the point.

 

Doug, 

The GC32 will foil in lighter TWS than I have ever seen an AC45 foil and I have never seen an AC45 foiling upwind, ever, in any wind conditions... There are a number of reasons for this, mostly related to the foil design and righting moment, but also platform stiffness and a few other bits.

 

The G4 looks cool, and I think there will be some fun rides on the boat. I don't envy your job of engineering the foils for full flight!



#35 floater

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Posted 15 May 2014 - 04:43 AM

^
I watched the Artemis AC45 fly upwind just yesterday - but rather sporadically - and not very close to the wind. So, from what I have seen, the statement that it cannot foil upwind is more or less accurate.

But don't know if they have attempted to optimize for upwind foiling either. Somebody said that Adam May retrofitted the foiling setup in something of a rush - and it worked first time (albeit with NO at the helm)!

#36 STYACHT

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Posted 15 May 2014 - 08:00 AM

STYACHT, thanks for the intelligent contribution to the discussion.

 

I know the polars link on the front page shows the C-Foils but the polar chart looks a little wacky. Are the max speeds off the wind really that deep? I could see max vmg being that deep, but would expect boat speeds to be higher in the +-120 range. 

 

Lat21, I am pretty sure the reason is the CL CD we have used as a starting point for the sails.  We are dealing with JB from NS, and were kind enough to get some data on a number of downwind sail designs for boats of this type, in the form of a trendline.  Not having any better data for the sails in our VPP, this was input.  As we get down the track with sail design we will get more accurate data from NS, and I fully expect this to change the polars.



#37 STYACHT

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Posted 15 May 2014 - 08:02 AM

Hi all,

 

the discussion above of (take your pick) really full foiling, area of foils, shape of foils does not, at first glance, make any mention of either TWS or boat speed.  An AC45 can foil in not a lot of TWS and has speed through the water considerably better than that windspeed when it does.  It can do this at a pretty wide range of angles too, because it is lighter by far than the G4 and the rig (wing) are prepped for it.  I doubt the GC32 has as broad a foiling range as the AC45, but that is not the point.

 

Doug, 

The GC32 will foil in lighter TWS than I have ever seen an AC45 foil and I have never seen an AC45 foiling upwind, ever, in any wind conditions... There are a number of reasons for this, mostly related to the foil design and righting moment, but also platform stiffness and a few other bits.

 

The G4 looks cool, and I think there will be some fun rides on the boat. I don't envy your job of engineering the foils for full flight!

Macca,

 

I stand corrected.  Thanks for that.  

 

I do recall seeing the GC32 foiling in very little wind recently.  Impressive to say the very least. 



#38 Monkey

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Posted 15 May 2014 - 01:47 PM

correction:
David Keiper was well respected and his boat foiled very well for the technology available then. The technology available now with UptiP foils is way superior to what Keiper used and is certainly capable of being used in an application like the G4.
Gunboat has a rep for quality and performance and they sure as hell wouldn't draw pretty pictures of UptiP foils just for the fun of it.
 
PS There is more to the use of foils than just speed! Foils can improve the ride and improve handling in rough conditions. And flying at any speed is just plain fun.
 

Doug, I've gotta ask, where did the Capitol P on uptip come from...surely acute Ls is a more descriptive way of putting it!
Just ignore it. He does this sort of thing where he makes up terms and then regurgitates them endlessly hoping people latch onto them. It's just a desperate attempt to be relevant. Then when he gets really antsy, he starts changing font colors and using long lines of equal signs after posts. It's a bit weird, but if you just ignore him, the threads stay mostly on track.

#39 bwd

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Posted 15 May 2014 - 02:46 PM

...

AC45s had 1.4ton displacement and needed a wing and 5 pros to fly.

Both Cali 45 and G4 will be pushing reality to get below twice that displacement, with soft sails and crewed by 2-3 mere mortals.

The numbers on the GB site indicate with loo, fresh h2o etc there will only be about 1000 lbs allotted to humans and all the things a boat is full of.

Won't the owners want to share their fun a bit more generously without dogging their new toys?

Although, on second though, that could be me, one pro crew, and a half dozen supermodels... never mind. ;)

 

Also from the renderings it is amusing to note those who distinguish themselves poorly at the the heads may exit via a round aperture to commune with marine life without further embarrassment above decks.

3613.jpg



#40 Doug Lord

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Posted 15 May 2014 - 02:46 PM

correction:
David Keiper was well respected and his boat foiled very well for the technology available then. The technology available now with UptiP foils is way superior to what Keiper used and is certainly capable of being used in an application like the G4.
Gunboat has a rep for quality and performance and they sure as hell wouldn't draw pretty pictures of UptiP foils just for the fun of it.
 
PS There is more to the use of foils than just speed! Foils can improve the ride and improve handling in rough conditions. And flying at any speed is just plain fun.

 

Doug, I've gotta ask, where did the Capitol P on uptip come from...surely acute Ls is a more descriptive way of putting it!

 

I don't know about that. Take the front page where Scott  or Clean interviewed the Gunboat guys: Scott or Clean used the term "J" foils while Gunboat guys used the term "L" foils-both were referring to UptiP foils. The a,b,c's of these foils are not well understood-even though the inventor uses the term "L" foils. But with UptiP there is no doubt that I am referring to the uptip "L" foils invented by Morrelli and Melvin/Team New Zealand along with the single main foil/two rudder T foil configuration which is critical to the foils performance.

I was trying to find a way that I could talk about these foils in a way that there is no doubt what I'm talking about. When you have different people referring to the same foil as "J" or "L" it's confusing to a lot of people and the configuration is not included/understood. I'm hoping that by using "UptiP" both the foil type and the configuration on the boat will be understood.

 

Pictures-L to R- 1) "L" foil +single main and 2 rudder T foils(Tspeer pix), 2) UptiP foil, flying Phantom,(from Foilers!), 3) "J" foil from Hobie Trifoiler, Greg Ketterman:

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#41 bloodshot

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Posted 15 May 2014 - 03:05 PM

 



 

Doug, I've gotta ask, where did the Capitol P on uptip come from...surely acute Ls is a more descriptive way of putting it!

 

...... I'm hoping that by using "UptiP" both the foil type and the configuration on the boat will be understood.

3352-Stop-trying-to-make-fetch-happ-D2L5



#42 hawk 808

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Posted 15 May 2014 - 06:40 PM

I acutally like the term. It is spot on!



#43 bush sailer

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Posted 16 May 2014 - 12:19 AM

Just looking at the rendering, obviously not a lot of effort has been put into the boat design at this stage. You can not actually get into the rear bunk because it would be impossible to open the door . If there was no door you would have to climb over the head........Nice



#44 THOR

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Posted 16 May 2014 - 03:01 AM

that's not a head its a pizza oven



#45 bwd

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Posted 16 May 2014 - 04:10 AM

inventor uses the term "L" foils

therefore those nobodies muddying the waters with other names, STFU

ahem, Doug.

...go play with your models.

 

Also, that door -- no worries mate, it's just a curtain!

But point taken, some needed bulkheads etc, may be omitted from the early renderings...



#46 Rudo

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Posted 17 May 2014 - 11:16 AM

...... Also from the renderings it is amusing to note those who distinguish themselves poorly at the the heads may exit via a round aperture to commune with marine life without further embarrassment above decks.

3613.jpg

whaa that comment made my day!!!

 

Thanks for sharing your thoughts in here.

Good observations on the privacy panels. We are working to omit a few bulkheads in there, and use full fabric panels with zip doors.

 

Cheers,

Rudo



#47 Amati

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Posted 17 May 2014 - 08:55 PM

My comment ties in to the AC trickle down thread:

Aside from beam rule limitations for the AC, I'm trying to understand where some sort of V hydrofoils wouldn't be better for the Gunboat- my concern has been the same as Tom Speer's- tip vortices.

Once the tip is out of the water what is the difference between the L or UptiP and a V or the like:

\|

\/

?

Twist?

I should post a pic of Mayfly. But a V foil rotated up is completely out of the water, no?

#48 Doug Lord

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Posted 17 May 2014 - 09:06 PM

Paul, if you haven't already, read what Tom is quoted as saying in post 126 of the "trickle down" thread and what Dario Valenza discovered almost at the end of the same thread.  A quick summary is that Tom Speer says its real draggy sailing with the UptiP tip  out of the water and Dario found that sailing with both UptiP foils in the water worked downwind when leeway was low.......

If you go to Tom Speers website he compares "V" foils with T foils and ladder foils:   http://www.tspeer.co...ils/generic.pdf

 

Picture below of Doug Halsey's "Broomstick" whose two main foils are "V" foils. He's a member on boatdesign-and a good guy-you could pm him with any questions.

Attached Files



#49 floater

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Posted 17 May 2014 - 10:39 PM

^
Aren't the V foils pictured above self correcting? The symmetry we see in the FP, GC, and proposed Gunboat foils are certainly looking more V - and less L.

Speers talks about drag from tip rupture as a no no for Americas Cup boats - but it seems to me that both the GC and FP are happy to air the foil tip. And for that matter, the AC72's did the same downwind.

#50 Doug Lord

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Posted 17 May 2014 - 11:48 PM

If by "self-correcting" you mean that they automatically maintain altitude- yes. But they do it like surface piercing foils-the faster they go the less foil in the water which is not how UptiP foils work(mostly) : UptiP foils generally work by the coupling between lift and leeway as explained by Tom Speers. However, Dario Valenza's experimental foils-both UptiP-worked sort of like "Broomsticks" foils downwind when leeway was low and both foils were down.



#51 Amati

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Posted 18 May 2014 - 08:02 AM

Are cantilevered foils as light and strong as foils supported on a minimum of 2 points?

Another approach?

Attached File  image.jpg   31.8K   104 downloads

#52 Wess

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Posted 18 May 2014 - 11:41 AM

Big fan of foiling and believe it will make its way to cruising applications sooner rather than later (and Gunboat seems an ideal platform to start with) but am having a hard time believing this Gunboat "press?"

 

PJ posts here regular both to support his brand and to criticize others a time back about foils on Gunboats.

 

His silence on this topic - foils on the G4 - maybe speaks volumes.  Or maybe not. But it sure is odd that the voice of the company is so quiet on this.  He has never been the shy type before.

 

Speak up Peter.  How real is this?  What is the plan?  Goals for the project?  Costs and expectations?

 

Wess



#53 Amati

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Posted 18 May 2014 - 01:13 PM

And while we are put on hold, something to while away the time that might amuse...


http://www.yachtbout.../hydrofoils.htm

#54 Kenny Dumas

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Posted 19 May 2014 - 06:15 PM

I wonder how much power it would take to make it foil under power as well as under sail?  And what the fuel efficiency numbers would look like.  Motorsailing would be interesting also with maybe a quick boost from the motor to kick it up on the foils. 

 

The one time my Solcat hooked up in a puff was surprising:  Running the 15 hp Yamaha at half throttle with just the jib up, doing about 8 knots.  Puff fills the jib just right and the apparent wind kicks in, unloads the Yammie enough to pop up the rpms and suddenly I'm doing 15 or so.  Of course this was ~100 yards off the beach, headed in to pick up the admirable, and you really need 3 hands to steer the rudders, handle jib sheet, steer / throttle the Yammie. Not too crazy, but did get my attention, including an appreciation for motorsailing apparent wind machines, lots to learn there. 



#55 Strategery

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Posted 20 May 2014 - 12:32 PM

I don't think the comparing this boat to the others in the Gunboat line works. This clearly has a different mission brief, and I'm interested to see what they come up with.  I don't see the target for this boat being cruisers. It's nice that you can sleep overnight, but I doubt my wife would spend a single night on the boat. This is more accommodation for crew at an away regatta...

 

Depending on the price, the G4 could be a hot OD platform for the M32 crowd looking for the next level of speed. 

 

Re: foiling... I think you'll see very gradual development of technique similar to AC racing where groupthink was upwind foiling was slow, but once the right technique was determined, it became the way to go. In any event, it will be fun to watch the lessons emerge, and as a group we need to celebrate ventures like this. The only boat (IMHO - no offense to any other designers out there...) that I've raced against that came close to this design spec is Merlin, the Wormwood 35, and without foils that was a FAST boat.

 

I really like that there's lots of trickle-down that the G4 team and Peter seem to be bringing from AC foiling, which is how it should be. Don't sleep on the Johnstone boys... this could be the development of an entirely new class of coastal racer (just like they did with the J24, J105 and J120)...

 

All this with only one cup of coffee...will be a good day I think. Thor - too funny on the pizza oven.

 

Best,

 

C



#56 bwd

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Posted 22 May 2014 - 03:45 AM

Thanks

de rien, mon ami

but if only i'd had some rum to hand,

less words...



#57 cleveland

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Posted 22 May 2014 - 05:53 AM

I said fully foiling not full of foils.
In videos that haven't had the playback speed doubled it is clear that the boat is not fast even during the moments it gets all its hulls out of the water momentarily:
If the foils get so large that their induced drag approaches or exceeds the drag of the hull(s) they are lifting then what's the point of foiling?
IMHO, the renders of the G4 are already looking too big and draggy.

 

It was a very fast boat. His book describes many examples of that. I think its also easy to see in the frame above the reduced foil surface actually in the water.

 

In his book he also describes many situations while cruising the pacific that indicate the ladder system with its reserve lift is ideally suited for cruising. Such as plowing into a trough running with the sea, and letting the bow pop up on its own. The beauty of this system is it not only provides reserve lift, but it requires no pitch control and has no moving parts. Something that all of the AC trickle down and up tip foils require. 

 

Williwaw used a ladder system on the almas (as well as the rudder) to prevent leeway in a very similar fashion to the inward pointed up tip foils that doug has been describing. The ladder system, I'm sure everyone is aware of, reduces wetted surface the faster you go making it more efficient making you faster etc.  It also contributes to ride hieght through ventilation like the up tip. His boat only required a few settings of the foil AOA and he would stop and change them by hand to suit conditions. A far cry from the OR72 board control system and optimization available today.

 

The main foil however was a single foil attached at the almas and the main hull, and had brackets which reduced the area of ventilation. It was supported on both sides due to the limitation of the materials available at the time, extruded aluminum, it also rotated up to the bow. Additionally the boat was very thin ply/epoxy, and had an extremely low windage deck. However it had an extremely inefficient rig, and was still able to easily achieve beam reach fully foiling. 

 

If you want to make an ocean crossing foiler it needs to be simple and automatic, carry reserve lift, and possess variable lift/drag ratio for take off vs cruise speeds. Something that Williwaw is alone in achieving. Ive always thought if someone were to try again they'd start there. 



#58 Easy-Sailing.dk

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Posted 22 May 2014 - 06:41 AM

Found this longer video of Williwave. About 3 min into the video you get a good look at the foils. They must have made a lot of unnecessary drag with all those vertical struts. It would be interesting to see how this ladder system would work on a cruser, if it build with modern materials.

 


 



#59 Torsten

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Posted 22 May 2014 - 07:51 AM

And while we are put on hold, something to while away the time that might amuse...


http://www.yachtbout.../hydrofoils.htm

 

Love it!  And if foils aren't quick enough he also does these... http://www.yachtbout.../Ekranoplan.htm

 

/hijack



#60 nroose

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Posted 30 August 2014 - 05:28 PM

Are any of these floating or in build yet?



#61 PJD

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Posted Today, 05:28 PM

working on it @ Holland Composites first boat ready before end of this year. www.hollandcomposites.nl    

 

https://www.facebook...?type=1   https://www.facebook...706263339427814






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