[Rhodes22-list] IMF

Sat Feb 17 11:42:31 EST 2007

Joe,

Why does a problem normally occur with the headsail furler?  I have usually found the problem at the fastening point on the mast.  I am going to help Luis with his this week.  

On the IMF it is better to reef on a port tack - look at potential friction with the sail slot and you see why.  Any other hangups I am aware of are based on preventative maintenance.  The internal workings of Stan's IMF are beautifully simple.

Art

-----Original Message-----
>From: Joseph Hadzima <josef508 at yahoo.com>
>Sent: Feb 17, 2007 11:08 AM
>To: The Rhodes 22 mail list <rhodes22-list at rhodes22.org>
>Subject: RE: [Rhodes22-list] IMF "Reefing"
>
>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
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