New Trimaran Foilers

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Gary, hopefully, this will help:
(for the "Trimaran Foiler" Thread)
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WOLF daughter of fire arrow
Specifications
Latest Update 4/7/19---Design 99% complete--ready to build!
Design by Douglas Whitcraft Lord--- with a little help from my friends
Inspired by Fire Arrow
System usable on trimarans from 10' LOA to 100+'.
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A) WOLF specs(tentative) :
LOA 15' 8"
Max Beam 16'
CL ama hull to CL ama hull-14'
Target weight 175-190lb
SA-(mast length 24' all carbon wing mast)
--upwind: 185 sq.ft
--downwind: 300 sq.ft
--max pressure before depowering/reefing:
-----UptiP Foils= 1.15 lb per sq.ft. sail area.
-----Welbourn Foils= 1.8 lb per sq.ft. sail area.
* NOTE-see "F)" below for max pressure comparison with an F18.
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SAIL LOADING- an indicator of hydrofoil performance. Divide weight in pounds by SA in sq.ft( reference: Moth= 2.86lb. per sq.ft. sail loading w 180lb crew).
WOLF- upwind SA 185, downwind SA 300. Weights using highest estimated boat weight* + 220lb for one person and +340lb for two people(MAX).
* 190lb
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upwind-one person=2.21 lb. per sq.ft. sail loading @ 410lb total flying weight
two people=2.86 lb. per sq.ft. sail loading @ 530lb total flying weight
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downwind-one person=1.37 lb. per sq.ft. sail loading @ 410lb total flying weight
two people=1.77 lb per sq.ft. sail loading @ 530lb total flying weight
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B) Advantages:
1-Singlehander- Excellent upwind and downwind performance with 220lb crew. Minimum crew weight 120lb. Two people for daysailing-max about 340lb.
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2- Will foil in 5 knots of wind with 220lb crew .
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3- Carbon rotating wing mast, carbon cross arms and carbon foils.
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4- Retractable foils(from cockpit). Mainfoil retracts flush with bottom and tips are designed to not dig into sand. Rudder foil retracts above bottom. Ama foils retract above waterline when boat is level.
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5- Extremely comfortable sliding seat on each side. Allows crew to move 1.75' outboard very quickly.
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6- Uses the Fire Arrow Foil System(like Fire Arrow, Gitana 17, Banque Pop, Macif , Macif jr(24'Diam tri) and Maserati)-- the same as the original system first used on the Fire Arrow Test Model- except the larger boats use two rudder t-foils on each tack. WOLF has two UptiP ama foils-one used at a time-and one wand controlled mainfoil for very early takeoff and capable of substantial downforce- all working with a single rudder T-foil. Downforce can be virtually instantaneous adding RM in response to gusts. UptiP foils stay down-no adjustment when tacking or gybing.
(see #16 below)
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7- Foiling throughout the wind range -including very light air-the essence of 3D SAILING!
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8- Assy Spin/Screecher retracted under the front deck.
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9- Boat folds from max beam to trailerable width in about 4 minutes. No waterstays.
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10- Mid (wish)boom mainsheet so sheet is always in forward hand and extension tiller always in aft hand.
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11- Quickly self-draining cockpit-large scuppers with backflow flap.
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12- Planing ama hulls designed for incidental contact with water at speed and for inadvertent contact at slow speed.
Adjustable angle of incidence of planing surface of each ama simultaneously. Angle of incidence of ama foil has to be changed when this is done. Planing surface starts at +4 degrees.
Uses Two-Stage Amas-see attachments below. They consist of a planing ama hull(Stage One) coupled to a "curved piece"(Stage Two) that provides extra buoyancy in the event of a knockdown. Curved piece facilitates high dihedral crossarms which keep the crossarms clear of the water.
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13- Planing main hull.
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14- Aerodynamic surfaces added to forward and aft crossarms. Adjustable flaps added on rear cross each side. Jib foot and forward part of main foot to be sealed to deck.
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15- Automatic Foiling: no foil adjustments required after shoving off the beach and lowering the foils.
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16- Adjustable crossarm dihedral for prototype to facilitate testing.


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C) ---Memorable quote from JG Baker, Designer and Builder of the Monitor foiler in the 1950's:
" The main need is to lower the wind velocities required for flying in order to increase the opportunities for high speed travel"

D) ---VPLP on the daggerboard main foil:
" On these big boats, when you ease a sail, it is a pain because it takes so long to grind it back in. But here you press a button and the angles of incidence change. And with the foil on the daggerboard you can use it to alter the flight according to the wind*. If it builds, rather than easing the sheet you increase the righting moment by increasing the angle and conversely, as it eases you can reduce it and let it fly more."
* done 100% automatically on Fire Arrow/ WOLF with wand controlled main foil.

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E) --- Fire Arrow Foil System-first of its kind on any trimaran. Elements developed first by Fire Arrow include:
1) the first trimaran in history to use UptiP* ama foils,
*invented by Team New Zealand
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2) the first trimaran in history to use a single wand controlled main foil capable of downforce,
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3) the first trimaran in history to use Two Stage Amas.(see below for Two-Stage Ama pictures)*

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F) Max pressure for F18 and WOLF before depowering or reefing :
1)-The max pressure for an F18 based on 229 sq.ft. upwind SA, CE at 16.9', 2-180lb crew on trapezes and 5320 ft.lb. RM is 1.39 lb/sq.ft..
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2) --UptiP Foils-Max pressure for WOLF with 185 sq.ft. upwind SA, CE at 14', one 220lb crew sitting in a comfortable sliding seat, and 2992 ft.lb RM* is 1.15 lb/sq.ft..
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3)--Welbourn Foils- Max pressure for WOLF with 185 sq.ft. upwind SA, CE at 14', one 220lb crew sitting in a comfortable sliding seat, and 4654 ft.lb RM* is 1.8 lb/sq.ft..
Note: Welbourn foils provide 1.56 times the RM possible with UptiP foils*.
*not including downforce automatically generated by the wand controlled main foil.
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G) *The Two Stage Ama Design offers a lot both Statically and Dynamically:
1-Statically- the boat is sitting still and hit by a hand of God gust. It is theoretically possible that the boat could be knocked over with the mast horizontal but the two stage ama offers reserve buoyancy after the ama hull itself is immersed by the immersion of Stage Two("curved piece") and yet it is not enough to fly the main hull. It is enough, however, to right the boat.
2-Dynamically-The ama hull has two levels of dynamic vertical force:
a. first and foremost the ama lifting foil that works from very low speed on up,
b. Second, and a sort of back up at speed, is the planing hull design of the ama. To start with on Fire Arrow/WOLF, the planing surface only comes into contact with the surface at very low speed with the ama starting to fly before the main hull does. And when the boat is flying the ama performs as reserve lift during incidental surface contact at speed.
*Also see here for more on two stage ama theory: High Performance MPX Foil/Self-righting Trimaran-The Test Model https://www.boatdesign.net/threads/high-performance-mpx-foil-self-righting-trimaran-the-test-model.36058/page-191


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UptiP Ama Altitude Control-pictures A & B----
Note that the ama is flying before main hull-note ama flight altitude:


Now that the main hull is flying and speed and load are significantly greater than in "A" above, note that ama flight altitude is the same! And that's due to the ama UptiP foil design(no moving parts) :

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WOLF Trimaran Foiler 2019

 

Bonkers? Very much so.

 

In obviously far less exciting, real world news, Len Surtees' Sting 600 has had a successful first tow test.....



https://www.sting600.net/ for some further details of the test

 

Congratulations to Len. He said that she took off at 10 knots.......
more:
STING #1 was towed by local Coast Guard. Peter Schwarzel joined me for this important first foil test. Peter has engineered the foiling profile and performance modeling along with the structural laminate construction for elevator and forward wing foils. Due to impending 20 knot winds and rain squalls our tow testing was limited but sufficient to prove foils had adequate lift. The forward foils were set in the plumb position and the two stage differential foils performed as design. We only needed to adjust rudder elevator two clicks to achieve flight. The turbulence from the tow boat two propellers was extreme and we were amazed that the wing foils produce any lift at all. Our next test will be under sail during the month of May.

 

In ideal conditions it should be great fun levitating. otherworldly ,. I suppose practicing depowering and diving for the surface will be the main safety learning curve, the boat is an impressive achievement. It will look great under sail

 

]ECU's Feelers and transverse rudders/ flaps, I still can't get over that pm when you repeatedly ignored facts and logic while pretending you couldn't understand[/QUOTE]

"I suppose, then , that this makes sense to you? I wish it did to me but I guess being a ",..deranged...nasty piece of work" has its drawbacks. Oh, well....... Good Luck!"[/QUOTE]

ECU's are electronic control units and there are millions of them all around the world in cars. I won't explain what feelers..sender units, and transverse rudders are as I don't think that is necessary because you talk about them everyday.
The thunderbirds were a show from the 60s that most kids would have seen, you could get up at 6;am or earlier and watch them, the early morning helped set the atmosphere for the show.
It seems to me that considering you reference Rudyard Kiplings' life, you didn't have much of a childhood.,.. that you genuinely don't realise what you're doing in the quote above and in previous correspondance ,. suggests the treatment you may have had to endure as a young person, so it has been normalised for you.
It is good you have found a place to express yourself and enjoy your passion, good luck in the future.

 

Well I had a great chance to look over Len's Sting 600 trimaran last weekend at the Bay to Bay trailerable yacht race. It is certainly a well thought out good looking boat. The folding mechanism looks and works really well. Len spoke about modifying the main hull by widening it a bit to increase buoyancy. He had one of his ama foils on display but didn't use them in the race.
We were sailing on a Corsair Pulse so were really excited to have a crack at the Sting and see which was faster. We won our division so I guess that means us We beat the Sting by 15 minutes on Elapsed time and also 15 minutes on Handicap (after about 7.5 hours of racing)

 

Those amas/floats on the Corsair look huge !

 

You are correct, the amas are massive and a beautiful shape. She slices through the swell/chop with ease. We've buryed her up to the cabin on with the kite up on numerous occasions and she just pops on up and takes back off again. She is a weapon in strong breeze but bogs down in light winds. Anything over 12 knots TWS is awesome. I=Unfortunately the Bay to Bay was very light, can't wait to face up to Sting in a decent breeze!

 

Thanks for the info gypsy28!!

 

I'm just a little jealous, so one ama/float can theoretically lift the main hull out of the the water, is that what is called 200% buoyancy?. The total weight of the craft won't submerge the loaded ama including down force caused by the full sail ?

 

Not sure how the buoyancy % works but we have had the main hull flying at times, that's a real buzz! Easier in flat water, not so much in chop

 

The 200% buoyancy as a design guideline is not easy to use for small trimarans because the payload is too important in % of the total weight and moreover itself variable (one, two, three persons, ...). Better to consider the weight of boat + a medium payload : when considering the two last Astus design by VPLP, their choice seems to be around ~ 135 % with :
Astus 16,5 : boat 210 kg, float 500 l
>>> with a medium payload of 160 kg : 500/(210+160) = 135 %
Astus 20,5 : boat 490 kg, float 930 l
>>> with a medium payload of 200 kg : 930/(490+200) = 135 %
Astus 16.5 http://www.astusboats.com/astus-16-5.html
Astus 20.5, un trimaran transportable, astus 18.2, astus 22, astus 24 http://www.astusboats.com/astus-20-5.html

 

I see what you mean with payload - an extra person makes a significant difference on a small tri, Gypsy's Corsairs' ama proportionally may look like [to me] they're more than 135%. The Astus 20.5 has a buoyancy of 930kgs in one Amas ,that is one cubic metre minus 70 kgs of structural weight of the ama approximately perhaps . If I understand this correctly a Pulse 600 weighs 450kgs so is probably very close to the same floatation in the amas as the Astus, thanks

 

Up date from Len on the Sting 600:
Hi Doug

Our foil sailing trials planned for two weeks ago didn't eventuate due to helpers not available at that time.
Past weekend we sailed in a big two day trailer boat race with over 100 boats. This is a 85 klm race with a overnight anchorage Saturday night in the Lee of Frazer Island.
There were seven 6m trimarans in our class ( including two Pulse 600 that had removed the factory top down spinnaker and replaced with a huge light air spinnaker that was over one third larger and also they used a custom made windward screecher which is not factory issued ) and 12 in the larger class, all trimarans up to 31'.
Saturday was a good day for us but Sunday was a shocker.
Saturday we won the 35 klm race and beat half the larger class trimarans.
Sunday there were light winds allowing a clear 40 klm down wind spinnaker run, and guess who didn't have a spinnaker. We watched the 100 boats sail off into the distance, ouch.
Now having discussions with my sail maker, haha
Despite the flogging we received on Sunday we came third overall and second in OMR due to our sterling performance on Saturday.
We would have clearly won if we had carried a spinnaker but we will try again next year better prepared.
Now for foil tests, Peter Schwarzel will be back in Australia from a visit to NZ in 8 days time, i will try to arrange sailing foil test with Peter at a big dam that supplies water to Brisbane and is only a three hour drive away.( there is a boat club house there as it is a popular sailing spot )
How is your project going, hopefully you can start soon.

Will keep you posted ,

best regards

len surtees