[Rhodes22-list] Jammed IMF:(

[Stan Spitzer]

sorry - it looks like my e-mail takes Sundays off and this never left 
here so trying on Monday.



On 5/12/13 10:39 AM, Stan Spitzer wrote:
>
> OK, I suppose I have to run aground more often to have the time to 
> respond to some of your occasional S.O.S. signals.
>
> The IMF never jams at boat shows, where it gets more use in less than 
> a week than most of you give it in a lifetime.  It does not jam on 
> demonstrations or rentals or even when//*I* go sailing which 
> admittedly has not been for several months now.  And there are owners 
> out there who have never figured out how to jam their IMFs.
>
> Why is that.
>
> It is absolutely a fool proof piece of equipment because it has no 
> springs or gears and merely floats freely in a chamber. (Well, maybe 
> "fool" proof is a poor choice of words since I know that most of you 
> who jammed your IMF are normally brilliant,)
>
> There are only three reasons for an IMF system to refuse your 
> bidding:  Mechanical.  Human.  And all others.
>
> Mechanical failure:  The sail may have ripped.  Or the sail may have 
> come loose from its connection at the top of its furling tube and 
> partially slid down its tube.  Or a bearing like the one atop the tube 
> may have come off.  That sort of rare stuff.
>
> Human failure:  You may have caused a mechanical failure like putting 
> a curve in the mast by incorrect rigging or trailing with the mast up 
> and everyone understands how hard it would be to roll up a carpet on a 
> "C" shaped core. Or you may have forgotten to undue a cleat.  (This 
> idiot almost always forgets the vertical locking cam cleat on the aft 
> underside of the boom.)  Or you may be standing on the line on the 
> cockpit floor.  Or you may have turned emotional; a hammer or lots of 
> extra force only makes your Rhodes fight back.  Be kind and thoughtful.
>
> What makes an IMF sail go inside its mast in a bunched up fashion:  
> Either your putting it away with the boom so high above horizontal 
> that more material than normal tries to wrap around the furling tube 
> at the same location;  visualize that carpet on the floor where you 
> fold over part of one side before staring to roll it up.  Or putting 
> your IMF sail away with the boat not pointed into the wind. Now you 
> can put your IMF main away in light airs with the boat in any 
> direction relative to the wind but in heavy winds, with the sail 
> taking just the right beating as it is being wrapped around the tube, 
> it could be in a folded position at that instant.   So, whenever you 
> can, follow the prescribed way to put away an IMF sail:  Boat pointed 
> into the wind with the topping lift supported horizontal boom having 
> naturally moved itself slightly to starboard of the boat's center 
> line.  Sounds complicated but actually it all can be automatic.  If 
> you are not one who likes continual fussing with sail shape, always 
> sail with the topping lift supporting the boom horizontally.  Then, 
> when you want to put your sail away, do it as you come about, just at 
> that moment when the boom has moved itself to starboard of the cockpit 
> center line.  With all these stars in alignment automatically, a pull 
> on the furling line puts the main sail away in an effortless instant.  
> Try it. You will like it once you get your body coordinated.
>
> Reason for having the boom setting itself to be slightly to 
> starboard:  The furling tube die (a proprietary GB extrusion for all 
> you out there who scoff at the Certificate of Support program) is 
> designed for the sail to wrap around it in a prescribed direction that 
> both makes the sail come out and go in easier because its wrapping 
> direction is already started by the tube's design and because that 
> angle with the wind that is established with the boom having moved to 
> slightly starboard of center, takes sail cloth pressure off the mast 
> slot while it is emerging from the mast, and conversely, when the 
> cloth is going into the mast.   With the boat not into the wind, when 
> in heavy winds, the cloth pressure against the edge of the 26 foot 
> long mast slot can get so huge as to make it unreasonable to expect 
> the sail to want to go back inside the mast without complaining - or, 
> for that matter, come out to sail ..
>
> The Others:
>
> Those weak on spacial relations might not consider that trying to pull 
> out a sail of cloth made not to stretch, cannot work if the boom is 
> held fast _below_ horizontal by the main sheet cleat. The explanation 
> is so simple that I can explain it.  The length of the back side of 
> the sail triangle cannot change. Lowering the aft end of the boom and 
> holding it there so it cannot rise means the sail length would have to 
> increase to fill this increasing space and that is impossible so the 
> sail simply stops coming out of the mast.  A good practice is for the 
> boom to be free and not locked down by the main sheet when taking out 
> the IMF main.
>
> If by chance a guest not attuned to all of the above common sense does 
> cause a sail jam it is easily corrected.  Not having had this problem 
> I learned its solution by seeing what the big boys with big In mast 
> furling did at boat shows.  They approached the mast, put two hands on 
> the sail cloth as close to the mast slot as reasonable and pulled the 
> sail material not out but /*straight down - */ The one place where 
> force is apparently not a no, no.
>
> In conclusion a huckster remark:  If along the way of various owners, 
> someone has re-mounted the IMF main too high or too low on its IMF 
> furling tube, it will not work properly.  I will not go into 
> explaining this here but think of two fat ladies (or governors) trying 
> to get through a doorway at the same time.  If mounted too low the 
> sail bottom will be rubbing on the top of the boom slider and causing 
> bunching - if mounted too high the designed pulling out angle gets 
> beyond its working boundary causing the problem of the two fatties 
> trying to go thru a doorway.   As the sail comes out of the mast it 
> should stay fairly parallel to the boom with about an inch of 
> continuous clearance.  The cut of the sail and its mounting on its 
> furling tube are important to the easy operation the IMF can provide 
> under all conditions.
>
> While early outhaul car systems will let you sail, the newer outhaul 
> car design (price C of S dependent) not only allows for better sail 
> shape through superior draft control, but keeps the sail bottom 
> continuously parallel to the boom and the boom much better in 
> alignment with sail direction, all of this allowing a broader range of 
> orientation to put the IMF sail in or out with greater grace.
>
> there is probably something I forgot but have to get to my physical 
> therapy.
>
> ss
>