[Rhodes22-list] How to improve Rhodes 22 upwind performance?

[ROGER PIHLAJA]

Rick,

You are confusing “mast rake” with “mast bend”.

Mast bend implies an actual bending of the aluminum mast extrusion.  As you noted in your post, the IMF mast is very stiff.  Also with the mainsail, bearings, and other machinery stuffed inside the IMF mast, bending it out of straight and true would be very bad for the system.

In contrast, mast rake is the angle the mast makes relative to the mast step.  As you know, the base of the mast pivots on the mast step.  The mast rake angle is established by the length of the forestay and the rest of the standing rigging is tuned to suit.  My forestay has a turnbuckle built into the lower end terminal and the over all forestay length can be adjusted ~ +/- 3”.  Raking the mast aft moves the center of effort (CE) of the mainsail aft.  All else being equal, moving the mainsail’s CE aft will increase weather helm or moving it forward by shortening the forestay length will decrease weather helm (or increase lee helm).  The early IMF mainsail rigs had a tendency towards too much weather helm when the mainsail was fully deployed.  In Mike’s case, because he flies a 130% genoa vs a 150% or 175% genoa, this weather helm would be even more severe.  The experiment I suggested wherein Mike would slightly furl the IMF mainsail a little at a time and then check for weather helm is a definitive test for diagnosing this forestay length issue.  If Mike does not have a turnbuckle built-in to his forestay, or if the turnbuckle is already as short as possible; then, he will have to get a rigging shop to shorten the forestay and then swage on a new terminal.  Or, Mike could get a bigger genoa.

Roger Pihlaja
S/V Dynamic Equilibrium

Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows

From: Rick Lange<mailto:sloopblueheron at gmail.com>
Sent: Monday, March 21, 2022 12:57 PM
To: The Rhodes 22 Email List<mailto:rhodes22-list at rhodes22.org>
Subject: Re: [Rhodes22-list] How to improve Rhodes 22 upwind performance?

No joke.  The IMF is absolutely stiff, so you can't rake it with a
tensioner or bend it with a boom vang to affect mainsail shape.

As with the jib, you shift the center of force by furling and unfurling.

The focus of tuning the IMF rig with its dominant jib is backwards from
what most people are used to.  First tune the jib, then adjust the main to
pull air most efficiently along the inner surface of the jib.

Regards,

Rick Lange


On Mon, Mar 21, 2022 at 2:07 PM ROGER PIHLAJA <roger_pihlaja at msn.com> wrote:

> Rick,
>
> Is this a joke?  With you I never know.
>
> Roger Pihlaja
> S/V Dynamic Equilibrium
>
> Sent from my iPhone
>
> > On Mar 21, 2022, at 1:22 PM, Rick Lange <sloopblueheron at gmail.com>
> wrote:
> >
> > Hi Roger,
> >
> > The IMF mast does not rake.  It stands for In Mast Furling.
> >
> > Regards,
> >
> > Rick Lange
> >
> >
> >> On Sun, Mar 20, 2022 at 8:46 AM ROGER PIHLAJA <roger_pihlaja at msn.com>
> wrote:
> >>
> >> Mike,
> >>
> >> Here’s an experiment to determine if you have too much mast rake.
> >> Assuming light to moderate wind so you can put up full sail, establish a
> >> close hauled point of sail, and trim both sails as good as possible.
> Take
> >> note of how much weather helm you have.  Assuming you have the IMF
> >> mainsail, reef the mainsail a small amount, say 6 inches.  Reestablish a
> >> close hauled point of sail and trim the sails as good as possible.  You
> >> should now have less weather helm or maybe neutral or even lee helm.
> Keep
> >> reducing mainsail area until you have eliminated all the weather helm.
> >>
> >> By shortening the forestay, the weather helm can be tuned out of the
> rig.
> >> I like the helm to be neutral to very slight lee helm in light air.  As
> the
> >> wind strength builds, the hull is going to heel over no matter how much
> >> rail meat you pile onto the windward rail.  I won’t go into the physics
> of
> >> why and how; but, the asymmetric wetted shape of the heeled over hull
> just
> >> naturally generates weather helm.  You counter this tendency towards
> >> weather helm by reducing mainsail area.  This moves the rig’s center of
> >> effort forward and reduces weather helm.  You want to leave the
> foresail at
> >> full area as long as you can keep the boat sailing on her lines and use
> the
> >> mainsail area to balance the helm.
> >>
> >> In light air, there is very little feel to the helm no matter how the
> rig
> >> is tuned.  The easiest point of reference is to have the rig tuned for
> >> neutral helm, especially for a novice helmsman.  So, even though the
> >> helmsman isn’t getting any feedback thru the tiller, he/she knows to
> simply
> >> center the tiller, and the boat will go straight.  As the wind strength
> >> builds and sail area is not reduced, the hull will begin to heel over,
> and
> >> weather helm will build.  The helmsman is now getting plenty of feedback
> >> thru the tiller.  If the weather helm gets to be tiresome; then, the
> >> mainsail area can always be reduced to take the pressure off the tiller.
> >> Even a few degrees of rudder angle off center develops an amazing
> amount of
> >> drag.  This slows the boat down and reduces pointing ability.  Remember,
> >> the boat is making leeway even when the tiller is centered, and this
> leeway
> >> is enough for the shoal draft keel, centerboard, and rudder blade to
> work
> >> together to develop the required lift for the boat to be able to point.
> >>
> >> Roger Pihlaja
> >> S/V Dynamic Equilbrium
> >>
> >> Sent from Mail<
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> for Windows
> >>
> >> From: ROGER PIHLAJA<mailto:roger_pihlaja at msn.com>
> >> Sent: Friday, March 18, 2022 7:32 PM
> >> To: The Rhodes 22 Email List<mailto:rhodes22-list at rhodes22.org>
> >> Subject: Re: [Rhodes22-list] How to improve Rhodes 22 upwind
> performance?
> >>
> >> Mike,
> >>
> >> A couple of things to check:
> >>
> >> 1.   Is your centerboard all the way down?
> >>
> >> 2.  Is your rudder blade all the way down?
> >>
> >> 3.  In 5-15 knots of wind, you should use the mainsheet and traveler to
> >> center the boom.  Make certain the boom is not rising up and there isn’t
> >> too much curl on the leech.  Make certain the mainsail foot out haul is
> >> tight.  Without battens, there is only so much you can do with mainsail
> >> shape; but, this will set you up to do the best that is possible.
> >>
> >> 4.  Use your backstay adjuster to get the sag out of the forestay.  It
> >> takes quite a lot of tension on the backstays to remove the forestay
> sag.
> >> Don’t be afraid of cranking on the backstay adjuster.  A mast head rig
> >> needs the forestay to have little sag in order to properly form an
> >> efficient slot with the mainsail.
> >>
> >> 5.  Refer to my rig tuning procedure in the archives to adjust the
> tension
> >> in the standing rigging.
> >>
> >> The Rhodes 22 sails best to weather if it is regarded like a big sailing
> >> dingy, as upright as possible.  There should be zero to very slight
> weather
> >> helm.  If you have too much weather helm; then reduce the mast rake
> angle.
> >> ie Make the mast rake more perpendicular to the deck.
> >>
> >> My guess is you have too much mast rake, which is giving you a lot of
> >> weather helm, and killing your ability to point to weather.
> >>
> >> Hopefully, these suggestions help.
> >>
> >> Roger Pihlaja
> >> S/V Dynamic Equilibrium
> >>
> >> Sent from my iPhone
> >>
> >>>> On Mar 18, 2022, at 1:49 PM, mm.bizlist1 at gmail.com wrote:
> >>>
> >>> Hi All,
> >>>
> >>> Now that I've been sailing my Rhodes for about a year, I'm starting to
> >> focus
> >>> on getting the best performance out of her.  While I mostly sail for
> >> fun, I
> >>> do race every couple of weeks and want to be more competitive.  In
> >>> particular, I have found that she does not go to windward very well for
> >> me.
> >>>
> >>>
> >>> I have a 130 genoa and the IMF mainsail.  Until very recently, I have
> >> been
> >>> routing the jib sheets outside of the outer shrouds and handrails. That
> >>> limits how much I can trim the genoa. Consequently, I can only tack
> >> through
> >>> about 100-120o.
> >>>
> >>> Recently, I tried running the jib sheets between the outer shrouds and
> >> the
> >>> inner shrouds.  That definitely improved my pointing ability
> >> significantly
> >>> at the expense of less than optimal headsail shape on some off wind
> >> points
> >>> of sail.  However, this configuration lets me use my jib cars to adapt
> to
> >>> wind strength and whether or not I am partially reefed.  I think this
> >> will
> >>> retain the ability to use a whisker pole on downwind legs.
> >>>
> >>> I did briefly try both of the inboard jib sheet fairlead/cleat
> >> alternatives
> >>> but using those would seem to require having a second set of jib sheets
> >> and
> >>> probably going on the foredeck to switch between them after rounding a
> >> mark
> >>> (I often race solo).  Also, those options eliminate the ability to
> >> control
> >>> the sheeting angle to the clew with the jib cars.
> >>>
> >>> I'd greatly appreciate your thoughts and comments about what you have
> >>> learned about how to optimize your boat's performance.
> >>>
> >>> Thanks,
> >>>
> >>>
> >>> Mike McKay
> >>> s/v Liber (2006/2018)
> >>> Allatoona Lake
> >>> Acworth, GA
> >>>
> >>>
> >>
> >>
>