Dave Franzel expands on his Sonar tuning guide by guy22

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									Dave Franzel expands on his Sonar tuning guide

Following the publication of Dave Franzel's expert advice on fast Sonar settings and techniques,
Steve Sleight asked him to expand on a few points. Once again, Dave very kindly agreed and
generously shares his knowledge:

Q:You refer to very light, light air, big breeze, etc. Can you put some Beaufort numbers around these
please?
A: You've definitely busted me here for using sloppy terminology. In paragraph 2, the kind of "light
air" where you want to allow the main leech telltale to flow more than half the time, and keep the
speed up to maximize keel effectiveness rather than trying to point, is any time you have two or more
crew inside the boat. (Is that 7 or 8 knots? I'm not sure.)

Once three or four crew are on the rail you can close the leech to where the upper leech telltale flows
half the time for better pointing.

"Very heavy air" where you may not be able to close the upper leech because in spite of everything
you might do to stiffen the mast the panel above the hounds stills falls off to leeward might be F5 and
up.

In paragraph 4, "very light air" where I like to heel the boat to give shape to the sails is anything from
zero to maybe 8 kts.

"Very big breeze" is the same as "very heavy air", where the mainsheet is on hard, the traveler
spends most of its time below the centerline and you have to ease the jib in puffs to keep the main
from ragging and to keep the bow up.

Q: You talk about rake at 25'11'' in 0-14 knots of breeze then reducing it as the breeze increases up to
almost 2'' shorter in 25 knots+. Can you expand on this please? What increments do you reduce it in?
For instance, borderline F4/F5 say 17 knots, how much shorter would you make it then? And does it
matter if it's flat water or chop?

A: I cannot put specific numbers to it. There is no question that rake is fast whenever you can sail the
boat flat. There are any number of reasons why this might be: First, it allows you to sail bolt upright
without lee helm, second, if you believe in "endplate" effect then both sails are closer to the deck,
third, lowering the boom definitely increases the effective range of the traveler which allows you
to keep the boom on or above the centerline even when the sheet needs to be eased. I have heard
more guesses as to why rake is fast upwind, but empirically, it is.

In conditions where you cannot prevent the boat from heeling, however, you will have weather helm
with 25' 11" of rake. In chop, where you may want to drive a bit more, you will have to heel more to
do that, and less rake will minimize helm under such conditions. I do use the two fingers and a thumb
method of determining whether the boat is sufficiently balanced. If it takes more than that to hold the
tiller extension then I would consider tightening the forestay more.

Q: Your talk about rig tension and a lively rig makes sense to me but both the light air setting (4"
circles in the uppers at rest?) and the heavy air 25+ setting of 600-800 lbs seem really extreme
compared with the settings used here. We'd typically follow the North/Doyle guides of from 210-300
lbs on the uppers. I'm not sure I could get 600lbs on with the Spinlock screws! Can you explain and
confirm your settings please? Also, since you can't adjust rig tension during a race, how do you keep
the rig in the boat if you start off with slack uppers and a 20 knot sea breeze kicks in?!

A: You're right that if you are set up for light air and a 20 knot sea breeze kicks in you may be at a
disadvantage relative to equally fast sailors that are set at 2-300 lbs, although that has happened to me
and has turned out to be less of a problem than I expected. While it is a more conservative approach
to keep your shroud tension in line with what the sailmakers' tuning guides recommend, I have had
success striving to find the shroud tension that gets the forestay pumping in rhythm with the waves.
And yes. You can get 600+ lbs. on the uppers with spinlocks if you want to, although I doubt you
could if the spreader angle is greater than 3" and you certainly have to chock the mast back (partners
in front) as well.

Q: The final question (so far!) - how do you adjust your chocks? The idea of being able to adjust
them from the rail as implied in your article seems like sailing in heaven to us mortals who have
wooden or plastic chocks that are a struggle to adjust!

A: I use an old Harken "magic box" screwed into the underside of the deck forward of the raised
part of the cabin. The control line leads back to a cleat on the panel and the business end is attached
to a high tech no-stretch line that I tie around the mast just below the deck. That allows us to easily
pull the mast forward to insert or remove partners behind the mast. The magic box gives an 8:1
purchase which could just as well be achieved with a 2:2:2 cascading system of mini blocks. The
problem I have not yet solved is how to jam partners in front of the mast in 20+knots. So far the only
solution I have come up with is to sail with a large and powerful foredeck crew.

								
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