Gino Morelli talks about the AC72 design rule
MORRELLI prefers Gore-Tex jackets to club
blazers. And he prefers multi-hulls to monohulls. Morrelli, age 55, is a multi-hull guru who has been
designing, building, and racing multi-hulls since he was a teenager growing up
in California. He has designed and
built some of the world’s greatest catamarans, including Region de Picardie and Playstation.
has the distinction of being the thread that connects every America’s Cup match
that featured a multi-hull. His first foray into the America’s Cup was back in
1988 when we was hired to help design the catamarans Stars & Stripes ’88 and
’89. Next, as partner of
Morrelli & Melvin, he was involved as in the design of BMW Oracle’s
trimaran, the winner of the 2010 America’s Cup. After the Cup match, Oracle
engaged his firm to help write the AC72 class rule for the next America’s Cup. Today,
Morrelli is a member of ETNZ’s AC72 design team.
Morrelli was born in 1957 in land-locked El
Paso, Texas, but his family moved to Newport Beach, California when he was 13. Morrelli
reflects, “Dad always built race cars out in the garage, so it seemed a natural
thing in our family to just go out and build something.”
That “something” that changed his life was a trimaran he and his family built in
their backyard when he was in high school. “We just couldn’t understand why
people sail mono hulls. So we built
the trimaran… and that was it…we just want to go fast.”
THE AC72 RULE
STEVE Tell me about the history of the AC72 rule.
First, who were involved in writing the rule?
GINO In our
office, there were Dave McCollough, Nat Shaver, Bobby Kleinschmit, Julia
Lillis, Pete Melvin and myself. Outside
the office, well it was kind of a vague thing. But we basically do our
iterations and forward it to Mike Drummond and
to Tom Ehman. And they kind ran it
through the Italian representative of Mascalzone Latino including Harry Dunning.
basically started off looking at all the existing kinds of class rules that
were close to relevant. And we
took the approach of trying to cut and paste from a lot of the existing
America’s Cup [rules] that they had…[regarding]…some of the descriptions of
materials, use of materials, use of building techniques, limitations.
build a restrictive rule or you could build a rule that allows innovation. Part of the debate was, if you didn’t
specifically exclude it–because you forgot something–then was it
included? So there was a lot of
debate on how you wrote the rule.
Especially looking at it from a standpoint of trying to prevent a gross
loophole, being exploited and basically, if one team finds it and nobody else
finds it, you get a wild card, and they’d blow everybody away.
our team. Three of us reviewed it
and three of us wrote it. Julia
was kind of the arbiter to a certain extent, or she was the one [who] physically
wrote the rule. She was kind of
like the secretary, and had to help take our internal battles and put them in
one piece of paper and then send them to Oracle. And then they’d get reviewed over there and edit it and send
back for revision, with questions.
And so we go through the loop several times. And basically myself and Bobby and Dave were on the attack
side. But we shifted sides. It wasn’t clear cut. But basically the main idea was that we
had a group of us, myself–kind of being the lead–to attack the rule. “What
will Juan K do?” [Juan Kouyoumdjian
is a yacht designer famous for finding and exploiting class rules] And that was our whole in-house joke at
the time. You got to really take
these rules apart and that’s how we proceeded.
think it was about a six-month process.
And at the same time we’re drawing boats, and drawing examples of each
characteristic of the rule, and then reviewing the drawings…to see if the
drawings made sense with the rule, and if you could draw something completely
crazy, would it be included or excluded by the verbiage.
part of it was to try to control cost and part of it was to try to prevent a catamaran
from turning into a trimaran, Russell [Coutts]’s idea, to his credit, was to
create the box tight enough that all the boats look essentially the same on TV.
You know, they’d look like Nascar, they’d look like Formula 1. You wouldn’t have a trimaran and a proa
and a cat and a kite boat. He
wanted them geometrically similar in one case so that there wasn’t a lot of potential
of an outlier having found an exploited advantage. Or if the conditions ended
up so bizarre that it ends up as a totally light air regatta and somebody who
bet all their money on light air won.
idea was to try to create boats that were forced to the middle of the design
window. And they didn’t have
enough weight to go off and exploit tiny little, crazy, complicated tweekers. You
know, like a boat that has too much weight available, a minimum weight class
that’s too high, you can add crap. You can start tweeking everything. You get
more adjustments. People might want to tilt the hulls or sling the boat. Going upwind we’re like this and then
down over like this, or you move the hulls in. We needed to eliminate and minimize all that stuff. And one
of the ways was to have a weight analysis that we ran through, and we tried to
predict what the boat should weigh.
making a lot of assumptions, but we had to put the weight in between a
bracket. And one of our big concerns
at the time was that the weight was going to be difficult to attain and
maintain the sweet spot of it, it’s strong enough, but it doesn’t allow enough
room for people to have a lot of room to build all these crazy additions, but
not so light that the boats were too fragile.
So that’s why you came up with the 5,700 kg limit.
GINO Right. We needed a bracket, because we didn’t
want to force people to weigh in and start shaving off, you know, kilos,
because they were 5 kilos over.
We didn’t want to put it on one number. So we gave everybody a bracket.
AC72 RULE AND HYDRO-FOILING
GINO We were
more inclined to let there be fully flying. We already knew we could fly little boats. And we knew the future was going to be
in flying. And we knew the power
to weight ratio was going to be in fully flying, at least for sure, downwind.
thought…it would be expensive, and you’d have to figure it out, but we could
put sensors on them like a big moth.
And we’d have fully articulating rudders, or flaps, and Oracle
agreed. And we have iterations of
the rule that have a completely different sets of words in it that allow fully
flying boats with, there was anything you could think of.
still have restrictions on it: you couldn’t exceed the beam, considerations that
you couldn’t reduce the righting moment.
But it was fully articulated.
And it was the Italians, Mascalzone Latino guys that basically came back
and put the kibosh on it, and kind of vetoed it. And Russell and the boys agreed. So we dialed it back.
And we dialed it back to the point where we had lots of arguments and
discussions on how can you restrict it without killing it.
only part in the rule that we restricted on the dagger board is what we call “translation”,
which is moving the board fore and aft.
And part of that is because when these boats are sailing upwind, the
center of effort with the small jibs or no jib is pretty far out. So you put up the big reacher and the
center of effort shifts radically forward. And if you had your way, you would, actually, rather than
rake the rig to account for the shift in the center of effort, you’d move the
wasn’t unconceivable that we’d have a dagger board that would shift a foot and
a half further forward going downwind to get back, because they’d get really leeward
helming. But the complication of shifting the lateral resistance was considered
too big a jump. It was too
complicated. So we restricted translation up to like 20 mils, which is just,
that’s just a tolerance so that the board can wiggle in the case and you don’t
get thrown out of the race.
daggerboard is located further forward than ETNZ’s board. Could that lead to
GINO Well, not
GINO Well, it
depends on how much importance you put on the rake. My feeling was, because of the super short courses, there’s
not enough humans on board to rake the rig, and put the reacher up, and sheeted
it, and jibe it, and get it back down 3 minutes later.
the problem with rake is cant. And
we’re trying to eliminate cant.
And that’s actually very difficult to do, because if you allow rake
adjustments it’s very possible that someone rakes the rig to weather. And how
do you control that on the race course?
Are you going to take photos of them? You know, how are you going to protest?
there’s also wire stretch and there’s mainsheet tension. So, in
fact, that’s still kind of a vague issue in the rule is: rake is legal, but cant is illegal. But I don’t know if we’re going to see anybody canting. Pretty
much everyone has figured out that the damn things are too fast, the course is
too small: you start fooling with
cant while you’re super powered up, going 40 knots, it’s just a formula for
disaster. We left that in the
rule, but we don’t think anyone is going to do it.
RULE 1.4 (k)
STEVE Tell me about rule 1.4 (k): “hull means
a canoe body, part of which displaces 45% or more of the AC72 Yacht’s displaced
volume when floating in measurement condition.”
GINO The idea
was that we were trying to define it as a “catamaran”. We were [also] worried
about asymmetric boats. One hull
would displace more than the other hull.
But by putting the hulls at 45%, you basically forced everyone into a
very symmetric shape. Part of the
reason for a symmetric shape, the thinking on the Oracle side was you could
build both hulls out of one mold, to save cost. If you built asymmetric boats you double your tooling
cost. But we didn’t want to say
50% because 50% would lead to a measurement problem. Because if one hull weighed 2 kilos more than the other
hull, then you’d have 49.00 and the other one is 51.00. So we gave it a little
bit of value to give you more wiggle room, to allow for unfairness, or to allow
for some discrepancy in the build. So it was really an effort to try to
complement the other rules, which define the boat as being symmetric.
not symmetric above a certain point because the decks are asymmetric because
you have cockpit openings and shit like that. But the idea was you could build a split female mold and
build two boats, two hulls out of it.
And you can build the two decks differently, port and starboard, but out
of one mold. And that’s, in fact,
what most of the guys end up doing… building one female mold and pulling two
hulls out it. But you can build a port and a starboard out of it. So your beam sockets point the right
way, and your chainplates are on the right side, and the inboard beam
connections are in the right place.
rule] was mainly to try to define it as a “catamaran”. Because there is a chance, because if
you look at San Francisco, you could say, well I’m going to make my port hull
slightly bigger than my starboard hull, because it’s the leeward side going
upwind. Or it’s the leeward side
going downwind, and I want a little bit more boat on one side than the other. I mean, you would make that
choice. You’d skew it if you knew
you were asymmetric on the course. So that’s to prevent that from being
exploited and someone getting carried away. Because you could change the shape of the boat if you wanted
to. You could have a port and
starboard hull that one’s better for upwind, because it’s a skewed course to
the prevailing winds up there. So
you really could have one hull finer than the other.
STEVE Artemis and Oracle protested that ETNZ’s boat
was able to implement large volume daggerboards because the hulls weren’t measured
with the daggerboards in the down position while in “measurement condition”.
What is your thought on this issue?
GINO The volume of the daggerboard typically has
never been such a percentage of the total boat displacement that we even
considered it. I mean, when they
came up with that rational as to why our daggerboards were so big we weren’t
even thinking of it. I mean, I was
definitely like, we didn’t think of that.
I mean, we didn’t know.
That was like a complete, oh wow, I guess our big daggerboards might
actually lift the boat more than 5%.
Like oh, that wasn’t the intent of the rule though. We weren’t trying to limit daggerboard
volume in any shape or form. And
that’s essentially what their protest was is that that was some sort of limit
on daggerboard volume. But the rule committee found, as we wrote it, that it
wasn’t intended as a limit of volume. [Morrelli subsequently explained: “We
were trying to limit Buoyant Lifting Bodies (BLBs) like a project for Navatek
that we were working on at the time.”]
VOLUME AT THE BOW
STEVE Tell me about volume at the bow. I know from your experience with PlayStation you’ve definitely wanted
more volume in the bow.
GINO Yeah. Well right now, you know, if the more
confident you are in flying, theoretically the less bow you need, and that
reduces windage–a big component of drag.
But if you’re less confident, or you know the conditions are going to be
such that you’re going to crash, and you’ve seen it where if the rudder stalls going
upwind, basically you go airborne for a sec and you lose rudder lift, then the
main foil has so much lift you pull a wheelie. And once you pull a wheelie, you crash. You got to have enough bow so that you
can survive the crash.
a finite limit, and you can choose, well, do we crash at 40, or do you crash at
30, or do you crash at 20? And
then you kind of play the game of “wow, we brought on a little more buoyancy
for the crash”, as opposed to assuming you’re sailing downwind and fully
foiled. You’re not using the hulls to prevent a pitch pole anymore. You’re
fully relying on your package to do the job. But if the foil breaks or the foil stalls, or you can’t get
the foil down or they can’t get the foil up, you got to have enough boat left
over to get around the course. We
joke that the hulls are a “foil delivery device”, but you still got to have a
boat that can do the job, independent of the foils because, you know, shit
happens. It’s a boat race.
FOILERS VS NON-FOILERS
STEVE Because each race is going to have one more
downwind leg than an upwind leg, how big of an advantage would Artemis, being a
non-foiler, need to have upwind to make up for their lack of speed downwind
relative to a foiler like ETNZ?
GINO At this
point, to me, they’re always going upwind again, to a certain extent. It’s just the sea state changes
directions. You know apparent
winds are still so far forward, that aero dynamic side of it and the
hydrodynamic side of it really doesn’t know which way it’s going anymore. So I don’t know that we’ve optimized
the boats to go downwind so much as we’ve optimized the boats to go with
apparent winds between 19 and 30.
The math typically says that if you can make it to the weather mark
first, conventionally you’ve always been able to hold off people downwind
because you have a controlling position.
boats have changed the story so much downwind that you don’t have big attack
angles anymore. There’s no
leverage left. Now if everybody is
sailing downwind at 165, 175, you know, there’s no leverage. It’s not like you get these separations
and you can hold somebody off in a corner anymore. I don’t know that optimizing for upwind makes any great
sense. How much faster they’d have
to go? Man, they got to be on the
pace downwind. I mean, you can’t
give up anything downwind because the delta between going 20 and 40, it’s like,
if you’re going 20 knots upwind and you got a 2% advantage or a 4% advantage,
you’re going to lose that, you don’t, if you give up 4% downwind for 4% upwind,
the speed doubled.
The VMG is
so much higher downwind, especially since the angles have gotten down. The VMG
upwind is still tacking through 40ish, 88 degrees. The VMG downwind has
suddenly gone down to this, or increased to this. So the advantages downwind have actually gotten better. And it’s like if you look at them when
you do math, I don’t know how you can afford to give up anything,
STEVE Rod Davis said sometimes it’s beneficial to
actually go against the stronger ebb instead of the lighter ebb because it will
increase apparent wind, which in turn will increase your overall speed. Does that make sense?
GINO Yeah, I
guess I can understand it theoretically, but part of the problem is, here’s the
racetrack and this is Alcatraz, this is the box. It’s so narrow…that you may not get a choice of which way to
leading you’re never going to do a jibe set. That would be like putting a gun to your head. So you’re always going to do a bear
way, even if you got 400 yards before you have to jibe out. That’s a much faster route than jibing
up here, because if you go from 20 knots upwind and you have to do a full
herniated return to do. It’s so
slow. You’re much better off doing
a bear way, even if it’s like un-favored for whatever reason, because now
you’re going 40, and then you do a clean jibe where you only lose 2 knots or 3
knots of boat speed than doing, you know.
You’re never tactically going to jibe or tack to go get something. One extra tack or jibe will be like a
throw away, in my opinion. And the
course is so short that those are like 90 seconds upwind.
 Gino Morrelli. Correspondence. March 7, 2013.