[Rhodes22-list] IMF "Reefing"

Sun Feb 18 08:13:31 EST 2007

Jim,  This follows my line of thinking....Wally


>From: "Jim Connolly" <jbconnolly at comcast.net>
>Reply-To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
>To: "'The Rhodes 22 mail list'" <rhodes22-list at rhodes22.org>
>Subject: RE: [Rhodes22-list] IMF "Reefing"
>Date: Sat, 17 Feb 2007 10:31:46 -0500
>
>It seems to me that the difference between IMF and conventional from a
>weight distribution standpoint is two fold:
>
>1.  The furling tube which is negligible and the weight of the mast
>extrusion, heavier than standard.  Both of these are fixed weights (fixed
>height above deck with the mast raised in sailing position) and can be
>approximated by a weight "x" at the midpoint of the mast (i.e., center of
>gravity or CG).
>
>2.  The weight of the sail (less than conventional, because it is smaller).
>Since it reefs and furls on a vertical roller, the CG of the sail also 
>stays
>at the same height above the deck.  The center of effort (CE) of the 
>furling
>sail will move down and forward as the sail rolls into the mast.
>
>Net effect, furling the IMF lowers the center of effort and not the center
>of gravity of the mast and sail combination, while furling the conventional
>sail lowers both the CG and CE.  The CG of the conventional mast/sail
>assembly is lowered by the weight of the sail, which is not likely a
>significant part of the whole.
>
>It seems then to come down to the additional weight of the IMF assembly 
>with
>sail vs. the conventional mast and sail.  I don't know this, but I am sure
>somebody here does.  Likely windage of the thicker mast extrusion might be 
>a
>factor in some wind conditions.
>
>For me, convenience trumps all.
>
>Jim Connolly
>s/v Inisheer
>'85 recycled '03
>
>-----Original Message-----
>From: rhodes22-list-bounces at rhodes22.org
>[mailto:rhodes22-list-bounces at rhodes22.org] On Behalf Of Bill Effros
>Sent: Saturday, February 17, 2007 9:55 AM
>To: The Rhodes 22 mail list
>Subject: [Rhodes22-list] IMF "Reefing"
>
>Wally,
>
>Comparing "reefing" on standard sails vs. IMF sails is very hard to do when
>discussing among sailors some of whom have never even seen an IMF.
>
>"Reef Points" result in noticeable changes in sail size. The IMF is
>infinitely adjustable. I often adjust my sail in increments of 5% of total
>sail size. I suspect most IMF sailors change the size of their sails 
>instead
>of using the traveler. We don't think of it as "reefing"
>-- it is an adjustment the sailor can quickly make in response to changing
>conditions.
>
>The extra weight of the mast is insignificant. Remember that your sail is
>larger, adding weight aloft compared to the smaller IMF sail. But, since 
>the
>boat is designed to be sailed upright, and can easily be trimmed to sail
>upright, the difference in performance due to weight is probably no greater
>in an IMF boat than the difference of carrying an extra bottle of rum. Or
>not.
>
>I carry my extra sail on the Genoa instead of the main sail. Both are
>infinitely adjustable while single handing. When conditions change, I 
>change
>the set of my sails, all by myself, so easily that even a lazy sailor will
>do it.
>
>I think the biggest surprise about the IMF is how well it works
>mechanically. The sail and mast are made for each other. There is no
>compromise here, and it is easy to extend and retract the sail under any
>conditions. My wife enjoys doing it.
>
>Our harbor is busy on weekends with a very narrow neck, rocks all over the
>place, and a 10 foot tidal variation every 6 hours. It is irresponsible to
>sail into the harbor if you've got a motor, and most experienced larger 
>boat
>sailors take their sails down just outside the neck, and motor to their
>moorings. We turn on the motor and don't even stop while we retract our
>sails. When my wife sees other wives trying to control flopping sails 
>inside
>lazy jacks she shakes her head in disbelief. When other wives see my wife
>roll up our sail they ask their husbands why they don't have sails like
>ours.
>
>Bill Effros
>
>
>
>
>
>TN Rhodey wrote:
> > Bill,
> >
> > Well I may be wrong here .....I guess it would depend upon how much
> > smaller the sail is verses the extra weight of mast. Way back when (on
> > the sailnet list) there was discussion about this. In my opinion even
> > if the mast weighed the same you still might need to reef sooner with
> > IMF. Pure speculation on my part and I will admit I may be totally 
>wrong.
> >
> > The R22 is small enough to be quite sensitive to subtle changes in
> > weight and trim adjustments. You pay a price with IMF in mast weight,
> > sail cut, no downhaul, no cunnungham, no battens (except for the new
> > rev). If you know how to use all these controls you can create a much
> > flatter sail. You would be surprised at the difference adding a vang
> > made even with IMF. I could still flatten the sail enough to make a
> > big difference ...sailing much flatter, fast, and higher into the wind.
> >
> > Everything is a trade off and for me the pros for IMF are well worth
> > any cons.
> >
> >
> > Wally
> >
> >
> >> From: Bill Effros <bill at effros.com>
> >> Reply-To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
> >> To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
> >> Subject: Re: [Rhodes22-list] Harken Lazy Jack
> >> Date: Fri, 16 Feb 2007 09:02:30 -0500
> >>
> >> Wally,
> >>
> >> Why would a smaller sail need to reef sooner?
> >>
> >> Bill Effros
> >>
> >> TN Rhodey wrote:
> >>> Joe, There are some performance trade offs with IMF. The sail is
> >>> smaller and I would think an IMF R22 would need to reef sooner but I
> >>> am just guessing. That extra weight aloft must have some effect on
> >>> balance.
> >>>
> >>> Wally
> >>>
> >>>> From: Joseph Hadzima <josef508 at yahoo.com>
> >>>> Reply-To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
> >>>> To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
> >>>> Subject: Re: [Rhodes22-list] Harken Lazy Jack
> >>>> Date: Thu, 15 Feb 2007 16:45:37 -0800 (PST)
> >>>>
> >>>> I've seen some other cool sail systems, some with sail covers so
> >>>> you only need to zip it closed. Several replace the slot in the
> >>>> main with a track system so even a kid could hoist the main, and it
> >>>> drops into right into the sail cover.
> >>>>
> >>>> A BIG advantage of the IMF (I believe) is the unlimited reef
> >>>> points. Another is that is remains protected in the mast during
> >>>> transport.
> >>>>
> >>>> I've only heard one mild complaint that the IMF mast is thicker,
> >>>> and thus hinders pointing performance a little, but like Stan says
> >>>> there are trade-offs ... unlimited easy to set reef points, or
> >>>> slightly better pointing with the possibility you'd need to bring
> >>>> down the main completely because you couldn't depower enough.
> >>>>
> >>>>
> >>>> And I only had a minor problem with lazy Jacks where one of the
> >>>> lines got wrapped around part of the sail, and we had to lower and
> >>>> raise it again. But this was aboard a 65 foot Schooner with gaft.
> >>>> So it was a little more trouble than if it was a Rhodes with lazy
> >>>> jacks :-)
> >>>>
> >>>> Speaking of the A28 video ... I like the piston powered Hoyt Jib
> >>>> boom for down wind sailing .. very nice feature.
> >>>> Notice it's a working Jib and NOT 175 gennoa!
> >>>>
> >>>>
> >>>> --- "Michael D. Weisner" <mweisner at ebsmed.com> wrote:
> >>>>
> >>>> > While viewing the AE28 video, I was impressed with the ease with
> >>>> > which the owner was handling the main. He was using a Harken Lazy
> >>>> > Jack system (installation manual at
> >>>> > http://www.harken.com/pdf/4058.pdf.) At West Marine, the small
> >>>> > Harken Lazy Jack is about $200.
> >>>> >
> >>>> > Has anyone ever used the Harken Lazy Jack on an R22 main sail?
> >>>> > Does it interfere with boom movement? Does it jam easily?
> >>>> >
> >>>> > I know, with IMF, you have no need for it. I still haven't been
> >>>> > able to justify the cost of the new IMF mast & hardware on our
> >>>> > R22.
> >>>> >
> >>>> > I was just thinking that the Lazy Jack looked interesting. Maybe
> >>>> > run the control lines (downhaul &
> >>>> > halyard) back to the front of the cockpit, next to the pop-top,
> >>>> > opposite to Genoa furling line. Comments?
> >>>> >
> >>>> >
> >>>> > Mike
> >>>> > s/v Shanghai'd Summer ('81)
> >>>> > __________________________________________________
> >>>> > Use Rhodes22-list at rhodes22.org, Help?
> >>>> > www.rhodes22.org/list
> >>>> >
> >>>>
> >>>> __________________________________________________
> >>>> Use Rhodes22-list at rhodes22.org, Help? www.rhodes22.org/list
> >>>
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