Trifoiler impressions (speedfoil)

Trifoiler impressions (speedfoil)

Post by Hen.. » Wed, 19 Jul 1995 04:00:00


Hello there,

two guys at my little sailing club here in Germany have recently acquired
Trifoiler hydrofoil sailboats. Well, these are boats, not windsurfers, but
they are so goddamn fast that I think a little note is appropriate in this
newsgroup, too.
The trifoiler is a design by David Ketterman, known to the speed crowd for
his work with hydrofoil speedboats. His last all-out speedboat was the
`Longshot', which clocked a remarkable 43.x knots. It's a bit unclear
wether hydrofoils will go much faster, as the current technology has hit
a major wall in form of cavitation (which kills wing lift and increases
wear almost catastrophically).
Now, he's built a mere-mortal hydrofoil that's shaped like a `T', with the
top of the `T' forward. Two L-shaped foils are at the left and right corners
of the `T', and one T-shaped foil (which also is the rudder) is at the back.
The main hull is in the center, pencil-shaped shaped like a race car. Two
auxiliary mini-hulls are on the corners of the `T', to prevent capsizing of
the craft when the hydrofoils are not generating lift. Two windsurfer-like
sails of 10 sqare meters each are positioned on top of the auxiliary hulls.
The two sails are synchronously operated via a rod that connects both of the
`booms'. Extra stability for this two-sail rigg is provided by another,
static connection rod that connects the two mast about 1/3rd down from the
mast top. From the front, the assembly of beam, two masts and extra conrod
looks like a rectangle.
The pilot (yeah, pilot; and you should wear a helmet in this thing) is lying
feet-first in the center hull, with foot pedals for the rudder. Additional
controls are for sheeting in the sail and for lowering/raising the L-shaped
front foils.

The ride

First, get the thing into the water. As it is very wide, wider than long,
you usually push it in sideways, with all foils hauled up. Then, one
manoevers into deeper water .. either by pulling it by hand, or by paddling.
You feel very silly, slow and crippled at this stage. Now you reach deeper
water and lower the rear T-foil by hand and lock it into position. This feels
like making a plane ready to start. You paddle a bit in between to prevent
the craft from drifting around in circles. Then you get into the seat
and adjust it's position so that you can reach the rudder pedals ... things
start to look better. No more paddling, and you can use the pedals to maintain
some kind of direction while you fiddle with the front foil controls to get
them down into the water. You make sure they are locked in position, else a
disaster would be round the corner. Now you sheet in and zoom off ... No,
you don't ! First you think `Am I going to survive this ?'
What happens next depends on the wind strength. If the wind is below 3 Bft,
you'll be mostly drifting and still be looking silly. Otherwise, or if you
catch a lucky lift-off puff (3-3.5 Bft), all hell breaks loose. The front
foils lift off first, your tail (with the pilots weight in it) drags a bit,
some spray may hit you during the transition. Then, the tail foil lifts off.
You realize (afterwards, at least), that your craft has just reduced it's
wetted surface area and drag by 90% ... don't strain your neck and hold on!
The apparent wind shifts quickly to very frontal, as your boatspeed component
is so big. Now you know why the sails have so little chord. Sheet in more.
At force 3-4 winds, the boatspeed indicator occasionally hits it's max at
35 mph. At force 6 winds, it will be stuck at the max all the time (we
measured speed against the local Search-And-Rescue boat and got roughly
70km/h, about 44 mph).
Let's assume that you haven't hit another sailboat yet. So, you regain
partial control of your senses and try to go in a straight line. Why the
hell is the craft still going level ? Because the Trifoiler has automatically
adjusting foil angles, with the leeward foil producing uplift, and the windward
foil downlift, locking the craft into the water. The mechanical system is so
good that it locks the wings into position with an accuracy of +- 2 inches.
You can hear the `feelers' that protrude forward from the auxiliary hulls
track the water surface many times per second, much faster than a human
operator could.
Next step. The lake which used to be big is already at it's end. Your
approaching the shore. Time to jibe. How to do that ? Step on the rudder
pedal, mate. WHAM. Your head hits the outer side of the hull with full
centrifugal force. That's what the helmet's for ! You try to make the
turn tight (and it is very tight), so that you stay foilborne throughout
the whole manoever and don't need to lift-off again after completing the
turn. Again, the trifoiler stays level, even under the extra strain of
the centrifugal force in the turn. Time to accelerate ...
After an hour, you're worn out. You sail home. The people I've seen
step out of the Trifoiler look like they've just been pulled out of the
North Atlantic after their ship sunk: Quiet, small, literally mumbling.
But after you get used to it, it's part of the future of sailing: a
total trip.

Winds permitting, we want to make a speed check. Me on my speed needle
against trifoiler, winds force 6. It seems that they will win, though.

Cheers,
    Henrik `4.9' Klagges

 
 
 

Trifoiler impressions (speedfoil)

Post by mbri.. » Wed, 19 Jul 1995 04:00:00

Quote:

> Hello there,

> two guys at my little sailing club here in Germany have recently acquired
> Trifoiler hydrofoil sailboats. Well, these are boats, not windsurfers, but
> they are so goddamn fast that I think a little note is appropriate...(much
> deleted)... it (speedometer) will be stuck at the max all the time (we  
> measured speed against the local Search-And-Rescue boat and got roughly
> 70km/h, about 44 mph).

> Cheers,
>     Henrik `4.9' Klagges

This sounds great Henrik.  I just have to ask one more question...

Does it cost more than $299 (US) ????

 
 
 

Trifoiler impressions (speedfoil)

Post by Hen.. » Wed, 19 Jul 1995 04:00:00

Quote:

>This sounds great Henrik.  I just have to ask one more question...
>Does it cost more than $299 (US) ????

Haha, sure. The prototypes in Germany sold for 30.000DM, i.e. some 18k $
ex sales tax. But, that means in the US they cost some 15k. That's not
more than a comparable catamaran costs, say an olympic class Tornado.
Also, these are prototypes. Ketterman tries to sell the concept to
Hobie. If he succeeds, you'll see the price cut in half at the least.
The technology is not so special, except for the wings and their joint/
bearing.

A nice speed needle with carbospar and Neil Pryde's will cost 2k $'s ..
and the Trifoiler is a two-seater. It's a great toy if you want to get
rid of your spouse - just take her for a ride :-) !

Cheers,
    Henrik `4.9' Klagges

 
 
 

Trifoiler impressions (speedfoil)

Post by Jan B » Thu, 20 Jul 1995 04:00:00

Henrik:
do you have any drawings/articles of this thing?
I am contemplating building a sailboard on foils this summer (mainly for earlier plaining).
(see thread on WS on hydrofoils)
Jan

: >This sounds great Henrik.  I just have to ask one more question...
: >Does it cost more than $299 (US) ????

: Haha, sure. The prototypes in Germany sold for 30.000DM, i.e. some 18k $
: ex sales tax. But, that means in the US they cost some 15k. That's not
: more than a comparable catamaran costs, say an olympic class Tornado.
: Also, these are prototypes. Ketterman tries to sell the concept to
: Hobie. If he succeeds, you'll see the price cut in half at the least.
: The technology is not so special, except for the wings and their joint/
: bearing.

: A nice speed needle with carbospar and Neil Pryde's will cost 2k $'s ..
: and the Trifoiler is a two-seater. It's a great toy if you want to get
: rid of your spouse - just take her for a ride :-) !

: Cheers,
:     Henrik `4.9' Klagges

 
 
 

Trifoiler impressions (speedfoil)

Post by Hen.. » Fri, 21 Jul 1995 04:00:00

Quote:

>Henrik:
>do you have any drawings/articles of this thing?

seen from above:

              Sail 1\
                     \
                      \   front foil 1
                       \ F
                        \F         protruding tracker `feeler'
                     ====\===-----O
             aux. hull   |                                                
                         |                                                
                         | beam                                              
                         |                                                
sym. rear foil           |                                                
                         |                                                
F |--------------___________
F-|     Pilot    ___________=========      -> direction of movement
F |--------------        |
              Sail 2\    |
                     \   |
                      \  |
                       \ |
                        \|         protruding tracker `feeler'
                     ====\===-----O
              aux. hull  F
                         F
                          front foil 2

(metal rod connecting sail 1 & 2, sail booms, wiring not skizzed)

Quote:
>I am contemplating building a sailboard on foils this summer

I wouldn't waste the time building a WS on hydrofoils. I expect it to have
only very marginal advantages over a normal modern board with good fin. The
reasons why the trifoiler works so well are the adaptive foils and the large
width of the craft. Both you probably can't do right on a WS, or at least
it will take a large amount of effort. (Now thinking of it, you could use
your WS just like the center hull of the trifoiler, and employ a large
frontal beam ...)

Cheers,
    Henrik `4.9' Klagges

 
 
 

Trifoiler impressions (speedfoil)

Post by Gavin Stevens » Wed, 26 Jul 1995 04:00:00

Quote:


>Subject: Trifoiler impressions (speedfoil)
>Date: 18 Jul 1995 09:58:46 GMT
>Hello there,
>two guys at my little sailing club here in Germany have recently acquired
>Trifoiler hydrofoil sailboats. Well, these are boats, not windsurfers, but
>they are so goddamn fast that I think a little note is appropriate in this
>newsgroup, too.

>Cheers,
>    Henrik `4.9' Klagges

I saw one of these Trifoilers in Auckland a couple of months ago, looked like
heaps of fun for the two guys. About 2 hours to rig, struggle into the water,
jump in, get hammered by the onshore wind and chop, almost capsize, hit the
shore, zip off the bottom of the sail and almost capsize again. "That looks
like a good time" I thought as I sailed by*** onto my 5m.

It really created a large crowd on the shore, and would be fast in flat water
but considering it needs a fair amount of wind to get going it does seem like
a lot of hassle compared to a windsurfer.

Gavin

 
 
 

Trifoiler impressions (speedfoil)

Post by Hen.. » Wed, 26 Jul 1995 04:00:00

Quote:

>I saw one of these Trifoilers in Auckland a couple of months ago, looked like
>heaps of fun for the two guys. About 2 hours to rig, struggle into the water,
>jump in, get hammered by the onshore wind and chop, almost capsize, hit the
>shore, zip off the bottom of the sail and almost capsize again. "That looks
>like a good time" I thought as I sailed by*** onto my 5m.

Sounds like instant disaster. Well. Doesn't take us 2 hours to rig, more
like 20 minutes. Push into water takes 5 minutes. Praying and rowing or
pulling out takes another 5. Ready to run...
Capsizing ? Only if you make a particular mistake, or go in waves of 3 feet
or bigger. We went full speed into the wake of the local lake tourist water
bus, expecting the end of the world, but it didn't happen. The particular
mistake is adjusting the
 
 
 

Trifoiler impressions (speedfoil)

Post by Randall P Dev » Wed, 02 Aug 1995 04:00:00

*************Notice**********************
What follows is an unsolicited report from a potential,... no, future
Trifoiler owner. Greg Ketterman, the Trifoiler designer, brought one up
to San Francisco Bay for a day of test sails and joy rides at my request.
This is being posted to rec.boats.racing, rec.boats, rec.windsurfing,
and to the Multihulls Mail List for your information and enjoyment.
*************End of Notice***************

Well!

Whew!

Whew-EEEE!!

The Trifoiler lived up to every performance expectation and more.

The winds were variable 8-12 knots, gusting to 20. (my digital wind speed
meter needs calibration.)  There was lighter than typical chop and a
large number of large dogs playing in the "surf".  The sun was shining,
the breeze was cool but not cold, the fog stayed south of us.  It was
a great day for sailing and nearly perfect for sailing the trifoiler.

Greg Ketterman brought a new boat he was delivering to a customer in Reno.
It was Hull #1 with the Hobie name on it.  It was in great shape.

The good surprises:

The boat was lighter weight than I expected. I thought we might have to
carry the boat piece by piece across the sand and assemble it at the water.
The boat AND trailer were hand pushed across the sand.  Two of us were
nearly able to lift the boat (completely assembled).  It was quite easy
for two people to slide it off the carpeted trailer and into the surf line.

The sails looked HUGE for such a small boat.  In the video, the helicopter
shots don't really give you an accurate impression of the sail area.  Of
course, the Trifoiler can handle sails that big. They also had "zipper"
reefing for those really windy days.  Slick!

The sails are much nicer looking than the ones in the video and brochure.
The sails seem well constructed and only time will tell otherwise.
They are a mylar/dacron combination which gives them no stretch. The
excess halyard detaches while sailing and a bungie keeps the wire portion
of the halyard under control. (Why didn't I think of that for my Hobie?!?)

In fact, all over the Trifoiler, there are refinements to the design that
this engineer really appreciates.  It has a very complicated set of control
lines.  It is more complicated (subjectively) than any beach cat I have
sailed, and possibly more complicated than having two racing dingies. The
good news is that Greg and Co. have reduced the time necessary to rig those
complications through thoughtful placement of cleats, bungie cords, shackles,
etc.  Greg did most of the rigging himself and it really did only take about
30 minutes.  There are a lot of lines but each is quickly and easily
attached.

The speed estimates of the Trifoiler are not exaggerated and the speedometer
on the boat is quite accurate.  I had a portable GPS unit out there with
me and saw speed bursts of 27 knots.  This corresponded quite well with
the speedometer reading of 31 mph.  The speedometer is a completely
mechanical device that relies on the water pressure at the leading edge of
the rudder.  Slick. No impellers, always accurate whether on or off the
foils. (It did seem a bit off at the -slower- speeds, though. :-)

I was able to take it out by myself and get it up on the foils.  It really
doesn't take much technique. I even managed a full jibe on the foils!
Practice will make me better but I can, right now, sail it fast on the
foils after 5 minutes of instruction.

Disappointments:

Under these conditions, this boat is  W-E-T!  Wetter than beach cats, wet.
Wetter than windsurfers, wet.  Sometimes hard to see, wet.  It is no
exaggeration to say that there were times when it felt like a salt water
garden hose in my face.  I already have 5 or 6 ideas about how to reduce
the 20-knots-of-salt-water-in-the-face problem.  If I can't do something,
I just won't choose to sail under those conditions (which were fairly
typical for the S.F. Bay). :-(

This boat needs a self-bailing***pit.  Mine will have one if I have to
put it in myself.  Greg admitted that they have been putting off that
addition.  The boat is otherwise quite complicated and the last thing they
need to hear are complaints about some one's self-bailer being stuck open.

This boat was brand new and had a problem with twist in the main (only)
sheet blocks. Once that was fixed, it worked fine for the rest of the day.
Also, one of the sensor arms broke in a non-critical place.  This did not
affect the demo sails in any way.

This boat does not tack.  Even Greg's tacks took (what seemed like) 30
seconds to tack.  I suspect when racing, it will be faster to turn a 270
degree jibe than to try to tack. This will clearly compromise the boats
upwind performance.

One of the large dogs took a dump right were we were launching.  Disgusting!

Summary:

It was a great day for sailing. Greg gave 15-18 demo rides. Every rider
returned with a BIG smile on his or her face. I am going to get one and
then fix the things that I didn't like.  I am going to race against "D"
class catamarans, F-27s, Antrim 30+s, and beat them all to the finish line.
I can't wait!

Starting around October, I am going to give (sell?) demo rides by
appointment so let me know if you are interested.

-=O=- Randy

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     o===\_/===o
  ~~l~~~~~l~~~~~l~~
    Fast on Foils