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Medicine Man, Redux
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Your
readers have been interested in the latest version of Medicine Man and
the trick new rig. The gist is the heavy, spindly aluminum mast was replaced
with a carbon Hall Spars rig with PBO standing rigging from Future Fibres
instead of rod. The weight difference allowed the bulb to be lightened
and more sail area added. Here are some of the details: For those who
are not familiar with this boat, it started in 1990 as a 56 foot ULDB,
kind of a mini IOR ULDB 70. Over the years the boat has seen dramatic
changes as technology and rating rules have changed. The rig was enlarged
and water ballast added in 1999 and for 2001 there was a wholesale makeover
with new 61 foot hull, deeper fin and bulb, rudder, but still the 1999
rig. This mast had actually started life as a SC 70 mast and, as a spare,
was available at a bargain. For Medicine Man it was re-tapered to fit
the fractional sailplan but maintained the masthead spinnakers. It was
never optimal but a good step in adding sail area when IOR went away and
it was time for "run what you brung" PHRF racing.
Although
the 2001 incarnation included water ballast for most racing, Medicine
Man was not able to use this for Transpac 2001 because the rating limit
for movable ballast boats was substantially slower than other boats. Consequently,
the bulb was heavier than we initially would have liked so we could get
through the first three days of beating and reaching. This was fine with
the aluminum rig but after Transpac, when racing PHRF, the rig was marginal
enough with the water ballast that we had limits on how may people could
be aboard and also use all the tanks. Too close to the edge for comfort.
Well,
for this year Bob ordered a new carbon rig which would not only take the
fully "tanked up" loads but also took advantage of the advances
in standing rigging. PBO standing rigging is new to the mainstream market
but has already been around the world in several of the Open 60's in the
Vendee Globe and this last Around Alone. It weighs about a third as much
as stainless steel rod and has a bit more windage for the same stretch.
Future Fibres has improved the end fittings over the early versions that
were lashed to Open 60 spars with bits of spectra. Those boats couldn't
go to weather anyway but the lashings on the early PBO rigged boats made
the windage huge. Hall Spars re-tooled their spreader ends to fit and
there are other changes like mounting the turnbuckles for the diagonals
at the upper end, by the mast, so that the toggle type spreader ends could
work. The beauty is the rigging is light enough that one person can lift
all the standing rigging for a 61 footer. Don't try this with rod, it
won't coil small enough let alone be light enough to lift.
PBO
is attacked by sunlight and chafe so Future Fibres has gone to great lengths
to protect it. The end fittings are fully coated in plastic so the fiber
is completely hidden and the main part of the rigging has a braided cover
that looks like rope but is also impregnated with a resin. In high chafe
areas, such as the bottom of the shrouds and at the upper spreader tips,
there is an additional braided cover that will also act as a wear indicator.
Hall
Spars did a great job on the rig as well. It is surely stiffer than it's
alloy predecessor, doesn't show ten years of age and Bob doesn't have
to worry about rivets dropping out. The combined weight difference of
the rig and rigging allowed us to make the rig 2.7 feet taller and also
take 500 pounds out of the bulb. Now, Medicine Man is at the displacement
we had originally planned and with Transpac's increased rating limit,
is rated for and can use the water ballast.
So,
how does it work? I sailed the Cabrillo Beach to Dana Point Race last
weekend on the Medicine Man and can say the difference was noticeable.
The boat adds water ballast at about the same wind speed but has significantly
more sail area and weighs less. The boat motion is noticeably different
as well, that 214 pound guy is not 30 or so feet up the rig all the time.
Great combined with the 500 pounds removed from the bulb. Upwind in 12
knots of wind, fully tanked up with the medium number one genoa and 12
guys hiking, the rig is straight and the leeward cap shroud was still
firm. Just like it is supposed to be.
Boat
speed is higher too, upwind performance is better as would be expected
by carrying more sail in the same wind speed. The photo posted in the
forum shows the start with Pyewacket fully up to speed and Medicine Man
about ready to eat some really bad air. Fortunately for us, this forced
us to tack away where we picked up a right shift and crossed Pyewacket
a couple of minutes later. From there Medicine Man returned the favor
and was able to stay ahead of them for the next mile or so until outside
the breakwater. A good feat against a boat 25% bigger. There was a long
light air beat to the West End of Catalina and Pyewacket used their speed
to get out into the new breeze earlier, rounding about 20 minutes ahead.
We were pleased they didn't look much further ahead when we rounded the
end of the island and could see them again. Downwind Medicine Man is a
real thrill where the combined benefits are less weight, less bulb drag
and more sail area. The boat really wants to scoot. Near the East End
the wind compresses against the cliffs and we saw more breeze but still
not any real waves. Eleven knots of boatspeed at 145-150 TWA was easily
achievable and in the puffs I think we saw a 13+ on a wavelet. Now the
game changed, the wind lightened and the trick was to figure how to cross
the wind shadow of Catalina and head for Dana Point 30 miles away. After
4 1/2 hours for the first 25 miles to the West End and 2 hours for the
next 20 down the backside, it was 7 hours for the last 30. Lot's of light
air and shifts up to 180 degrees with the average wind almost on the nose.
Pyewacket handled it better than we did and/or got through more of the
transition before it went really light and finished about an hour ahead.
Seems like it was increasingly worse for the boats behind because the
next boat finished over 5 hours after us. Still, an interesting outing
and great to have a hint of "Medicine Man's" potential for Transpac.
Wish I could go.
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A
great effort by all involved after months of planning to execute the changes
in the four weeks after Ensenada Race. Hall Spars built a great rig and
sent representatives to supervise rigging and stepping, Future Fibres
supplied the new rigging, SeaTek rigging services, Ullman and North Sails
built new sails and expanded previous spinnakers and Dencho Marine accomplished
the boat building tasks of re-shaping the bulb, building a larger mast
collar, moving the forestay chainplate forward and repainting as required.
Dick Horn squeezed an Americap II wanding and flotation measurement between
other people's schedules in preparation for Transpac. PHRF was given just
a few days to produce a rating and they came through with a number that
allowed the boat to race, even though it might be more punitive than they
might have assigned if given the normal deliberation time better comparisons
of the predicted speed changes.
Anarchists
likely have several questions. In anticipation of some of them, here are
a few questions and answers:
Q:Is
PBO rigging allowed in all racing?
A:
It is allowed in Americap II, most PHRF and IRC which are inclusive rules
and don't have many materials restrictions. IMS, Volvo 60, other box rules,
etc. allow only round steel shrouds, either wire or rod.
Q:
Is the speed advantage of PBO rigging rated?
A:
Sure, for Americap II the weight difference is measured as part of the
rig weight that goes into the pitching credit/penalty. The greater sail
carrying ability from the lighter weight is measured when the righting
moment is measured. The greater windage than rod is not measured so, a
course racing boat might stick with rod for the rating/windage advantage.
IRC asks rigging material and presumably includes it in their secret formula
and PHRF will obviously hit the boat what they believe proper .
Q:
What is the long term life of PBO rigging?
A:
I'd have to say it isn't entirely known but Future Fibres and other rigging
manufacturers should also be asked. Many boats in the last Vendee Globe
sailed single-handed around the world with PBO standing rigging and I
hadn't heard of a rigging failure. Mike Golding did have significant chafe
damage to a shroud but it didn't break. There was a forestay failure on
another boat, but it was reportedly rod. The UV in sunlight does damage
PBO so the advancements in covers are very important. It is recommended
that after a year or so a piece of rigging be removed and tested to compare
the breaking strength to original levels. On the positive side, PBO does
not have the brittle fatigue situation at the rod ends frequently seen
in leeward side diagonal shrouds swinging in the breeze then loading up
on the other tack. My prediction is we will see more of PBO.
Q:
PHRF rates water ballast, does Americap II also?
A:
Americap II has developed a measurement procedure for water ballasted
boats to measure the increased stability from water ballast and will include
it in the handicaps. This involves flotation measurements with tanks both
empty and full but should provide a fair assessment. We'll know more when
US Sailing recovers from the recent deluge of applications and posts the
results on their on-line scratch sheet.
Photos
are by Chuck Stevens, Medicine Man crew.
Alan
Andrews
President
Alan Andrews Yacht Design, Inc.
259 Marina Dr.
Long Beach, CA 90803
USA
Tel. +1-562-594-9189
Fax +1-562-596-1859
E-mail AndrewsYacht@compuserve.com
alan@andrewsyacht.com
Web www.andrewsyacht.com
05/29/2003
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