[Rhodes22-list] IMF "Reefing"

[Joseph Hadzima]

Hi Gang:

I assume no one on this list has ever had any major
problems with their Rhodes IMF. Is there any special
maintence required?  I was on a boat where the furling on
the head sail failed as the 160 was fully out.  I recall it
was a little dicey going foward and fixing the problem,
under the no so calm conditions.

the down side any time you add complexity to something, you
introduce another point of possible failure (plus
maintenance issues, cost, etc.).  I'm assuming Stan's
choice of materials, and his teams' workmanship minumize
risks, but I'd still like to know of any sea stories
involving IMF systems.




--- Jim Connolly <jbconnolly at comcast.net> wrote:

> 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 
> 
=== message truncated ===


HADZ (a.k.a. joe)

"That's what a ship is, you know. It's not just a keel and hull and a deck and sails. That's what a ship needs. But what a ship is... is freedom." 
-- Captain Jack Sparrow