[Rhodes22-list] IMF

[Jim Connolly]

I have needed to lubricate the IMF lower bearing once mid-season, only
because I forgot to do it before launching.  The mechanism is elegantly
simple.

I have also found it helpful to secure the sliding block that follows the
clew back and forth along the boom as far forward as possible when leaving
the boat on the mooring.  It is easy to do with a pair of tiny bungee cords
to the forward end of the boom.  The one time I didn't do this, we had two
days of gale force winds during the week.  The sliding block slid aft and
allowed the clew of the sail to flog in the wind as the boat swung on the
mooring.  The sail wrapped a bit tighter on the furling tube and exposed a
couple of extra inches of sail, and the loosened outhaul line flogged and
chafed a bit.  Easily fixed, but could have damaged the sail, too.

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 Arthur H. Czerwonky
Sent: Saturday, February 17, 2007 11:43 AM
To: The Rhodes 22 mail list
Subject: RE: [Rhodes22-list] IMF

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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