THOUGHTS
ON THE CARE AND FEEDING OF GADFLY
III
(Webmaster Note: This
article first appeared in the NODS , September 1995.
It is reprinted here by popular demand.
The author is the former owner of the “Marion Sails” loft in California,
and a former member of an America’s Cup Racing Team. He currently hails from Texas where he is working on a PhD in
Astrophysics.)
By Howie Marion
There was a great deal of
interest in the fine yacht Gadfly III (National #821) after the recent
World Championships. This boat has been owned and sailed by John Makielski
since 1982. As most of you know, they
both have seen considerable success and rarely miss a regatta. Last summer however, she was showing the
strain of years of hard campaigning without significant maintenance. So during
the early spring, we set out to repair and rerig Gadfly with the goal of making her simple and easy to sail. There
are so many variables in our sport that if you can exercise control over any of
them you should absolutely take advantage of the opportunity. In other words:
you can’t always predict a wind shift but you can wetsand your bottom.
Before we could begin work on
tuning and boat speed, we had to have a platform that was consistent and
repeatable. The area from the mast step to the chain plates and the centerboard
trunk must be absolutely rigid under all sailing conditions. On Gadfly, the forward bulkhead was broken,
the top of the centerboard case moved more than an inch to each side under hand
pressure, and the chainplates moved up and down about half an inch. The deck
area around the mast step was also compressed a full inch.
The first thing we did was to
rebuild the mast support between the deck and the hull. There are many good solutions to this problem.
We used 2 columns of 2 inch PVC tubing which were installed with a fiberglass
pad underneath and an aluminum channel at the top.
Next, we fastened this
support to the front of the centerboard trunk and to the bulkhead with glass
and resin. We were careful to establish load paths which extended all the way
to the chainplate anchors. The bulkhead
was reinforced and securely attached to the centerboard trunk. The two parts of
the center board trunk were filled with cloth and resin, and bonded together.
(This problem is unique to this hull and cockpit mold, If you don’t have one of
the newer boats, you can ignore the last sentence.) The chainplate anchors were
reinforced and bonded to the rest of the boat. All of this work was done with heavy glass cloth and epoxy resin.
It’s not pretty or light, but it is strong. I estimate that we added 25 pounds to the hull. Polyester resin would have been fine except
that epoxy had been used to install those plywood boxes that Gadfly used to sport. Remember: epoxy
resin will stick to epoxy or polyester, but polyester resin will only
stick to polyester.
Once Gadfly was again a solid piece of fiberglass, we improved her
cosmetics by painting the cockpit area and installing a wooden cap on the
centerboard trunk. The cap also serves to support a console for the control
lines led aft.
We’ll begin our examination
of the rigging at the top and work our way down. All mast dimensions on Gadfly, including mast band location and
jib stay location, are within one half inch of maximum height. For 95% of the
sailing done in National One Designs, it makes good sense to elevate your sail
plan to the maximum height allowed by the rules.
The mast rake is 25 feet, 6
inches. We measured this by raising the jib and setting the jib halyard tension
as we would for sailing in medium conditions. Then we tightened the back stay
to just remove the slack without bending the mast. The tape-measure was
attached to the main halyard shackle and the halyard was hoisted to it’s normal
sailing position. This is not to the sheave on most Nationals but should be
even with the top mast band. The measurement is taken from the halyard shackle
to the corner of the deck and the aft transom, at the centerline of the boat.
This number is intended to get you “in the ballpark.” It should be noted that there is quite a
variety of deck shapes at the mast step and at the transom in the National
Class. For each individual boat however, the mast rake number is relevant as
long as the measurement is taken the same way each time. Mast rake information can be used to adjust
your jib halyard settings when you use jibs with different wire lengths, and to
verify tuning procedures from time to time.
We pinned Gadfly’s spreaders to prevent them from
swinging. With no mast bend, the spreader tips are directly in line with the
shroud path from the mast to the chainplate. (You can check this with your
trapeze wires.) Fixed spreaders hold their tips further forward and out
compared to spreaders which swing aft as the mast bends. The mast remains
straighter on both axes and is much easier to control. There is also less
headstay sag. The NODRA rules have some ambiguity about the maximum spreader
length. It appears to read that the lengths are recommended and not mandatory.
I suggest using spreaders that are at least 18 inches long.
The mast is a Proctor Gamma
section. I don’t think the section specs are nearly as important as the fact
that your sailmaker should know the bending characteristics of your mast on
your boat. I saw a few mainsails at Leland which were new sails based on an
older design. That design was probably fast when the National used heavy masts
without much bend, but the sails did not look good on modern masts with aft-swept
or swinging spreaders.
John has acquired
many sails for Gadfly over the years and I have inspected all of them. My
favorites are the Fisher sails designed by former World Champion Rob Frechette
and built in 1989. These are the sails used by Sara & Joan at Leland. The
Main is an excellent fit for the current rig configuration, and the Jib seems
to be versatile through a range of conditions. Greg Fisher Sails is now a North
Sails loft. Mark Makielski is the class contact.
Gadfly is rigged for vang
sheeting. This style of sheeting uses the boom vang to control the leech
tension on the main, while the mainsheeting moves the boom laterally. Many
Nationals are rigged to use the mainsheet for leech tension and the traveller
for lateral movement. Both systems work well. The mainsheet is split on Gadfly, forming
a bridle at the end of the boom. The mainsheet cleat is on the back of the
centerboard trunk. I prefer this to the “headknocker” cleat on the boom because
you can trim easily in light air without jerking the boom around. The vang is a
cascading 8:1 purchase which leads to a hole in the deck behind the mast step.
It is easy to rig since the vang is never disconnected for travel. The tail is
led to the console on top of the centerboard trunk where it can be reached by
either crew member.
The backstay is led to the helmsman’s forward hand since most people
steer with their aft hand. Don’t forget that the helmsman’s proper position is
well forward in a National. (Notice the photo accompanying this article). The backstay
can be an easy way to depower in puffy conditions. If it is rigged to make it
convenient to use while hiking, a quick tug on the backstay control line will
bend the mast, flatten the mainsail and open the leech. As soon as the puff
passes, the backstay can be released which restores your normal mainsail trim.
Sara is very good at this technique.
The forestay and jib halyard are led to the
deck near to the mast step. The jib halyard is on an 8:1 magic box which allows
adjustment while sailing. The halyard tension is increased about an
inch in heavy air from the nominal medium setting. In light air, it is eased
about an inch. The forestay is always
slack upwind. Downwind however, the forestay is pulled tight in order to pull
the mast forward and allow the jib to fly further to weather. Joan works this
technique very effectively. In some conditions, this trim enables Gadfly to
sail at greater apparent wind angles without losing boat speed.
The intersection of the forestay
and the deck on Gadfly is 14 and 1/8 inches, and the center of the mast is 83 and ¾ inches
from the forward measurement point. The
chainplates for the shrouds are 94 inches from the measurement point and the
lowers are 3/4 of an inch
further aft. The fore and aft locations of Gadfly’s chainplates are
determined by the internal structure of the boat. The shroud base is 48¼ inches wide, or 24 and 1/8
inches off
centerline. This is very close to the
class minimum which allows the jib to be sheeted as closely as possible without
distorting the foot or the leech of the sail against the shrouds. Both the
upper and lower shroud tensions are increased 2 or 3 full turns of the
turnbuckles in heavy air, and eased 2 or 3 turns in light air. This adjustment
is only done at the dock, and in practice is rarely changed from a
light-to-medium wind position. The jib halyard control will also change rig
tension and is much easier to adjust while sailing.
The jib leads are fixed at 9
feet and 1 inch from the intersection of the forestay and the deck. They are 3
feet 4 inches apart (or 20 inches off centerline) for a sheeting angle of 10.6
degrees. Because Gadfly has narrow side decks this appears to be a much tighter
sheeting angle than found on some other boats, when in fact it is not so extreme. Since the mast rake changes very little, we decided to eliminate
all fore and aft adjustment of the jib leads. There is no track to sit on and
no arguments over lead position. If you want to open the jib’s upper leech, let
out the sheet a couple of inches. Gadfly has never had barber-haulers and we saw no reason to
install them now.
The jib sheets are led forward to the front deck for cleating. This permits the crew to roll tack
effectively and still pull in the jib without severe contortions. Boats with
wider side decks may not have this problem. We also use 1/4 inch jib sheets.
These sheets run more freely than fatter line which makes the jib much easier
to tack in light air. Every Gadfly crew member since this change was implemented has
started out complaining about the small sheets and ended up complaining when
they had to return to larger sheets in another boat.
The centerboard has a 5:1 uphaul and a 2:1 downhaul. The downhaul is necessary
due to the weeds on Gadfly’s home waters of Eagle Lake. The board must be raised
and lowered often to clear the salad from it’s leading edge. A 2:1
purchase is necessary because the board is bent slightly and jams in the trunk
when it is raised most of the way. Both
control lines lead to the console and are easily reached by either crew member.
Finally, we spent a great deal
of time working on our underwater surfaces. Gadfly’s centerboard and
rudder are Rich Ogrentz specials. They are 3/8 inch thick aluminum which is
light and stiff, but the edges had only been rounded off. That was a big
handicap in light air sailing compared to the thinner blades on many boats. We
faired the edges of both the centerboard and rudder to the inch and one half
maximum width permitted by class rules. The shape of the fairing is a knife
edge rather than an airfoil shape. I believe that the work on the blades
resulted in the single biggest performance gain Gadfly experienced.
The bottom of the boat from the waterline down, was sanded with 120,
220, and 400 grit wet and dry paper. I don’t believe that 600 paper adds
anything. The blades received the same treatment
There were many other minor
tasks such as filling little holes and adjusting hiking straps, etc. When you are sitting on the trailer, it’s
hard to anticipate exactly how systems will function under sailing conditions. If you do much rigging work, you can expect
to have to move a few things after sea trials. But by August we had achieved
our goal. Since Sara and Joan had
confidence that their equipment was well prepared and easy to use, they were
able to concentrate on sailing. They
certainly did that well at Leland!