R 22

Rhodes 22


IMF Sail Shape

One of my goals for this sailing season is to learn more about sail shape in various conditions and points of sail. This will be my first full season with my R22 and I'm anxious to learn all it can do. Will Gower posted an e-mail back in March where he mentioned the SAIL mag. article from the March 2002 issue. I remember seeing the article and meant to save it but now I can't seem to lay my hands on it. I also remember being a bit confused by it. Will paraphrased some of it:

  • Light air - traveler car to windward, mainsheet eased to allow twist
  • Medium air - traveler slightly above centerline
  • Heavy air - traveler car eased, mainsheet tight

    I'm assuming that applies only to beating.

    Our R22's have that back stay tensioning line. Under what conditions is it adjusted? (I know this is not to be confused with the so-called adjustable back stays that you change on every tack...thank God I don't have that.)

    Should the boom car on my IMF ALWAYS be slid up close to the clew of the sail if I'm reefed in? I may have mine rigged wrong. It doesn't move with the sail when I'm rolling the sail in or out. Perhaps it should. I've just been moving it by hand and it seems to stay put where ever I position it.

    I know the basics but by no means am I an expert. I've been reading through my copy of the Annapolis Book of Seamanship, Chapman Piloting and others which do a pretty good job of explaining sail trim, but the R22, with the loose-footed IMF and my 175% genny (with a nod to Roger and his explanation of the foam luff pad) may have specific aspects that aren't covered in a book of general sailing. Would anybody care to elaborate on this for me?

    17 May 2002

    Adjusting the position of the boom car relative to the clew of the mainsail ought to be a means of adjusting sail shape. I would think having the clew & boom car close to each other would result in the flattest possible sail shape (i.e. shallowest draft) for going upwind in heavy air. Increasing the distance between the boom car & the clew should allow the sail to assume a deeper draft shape for lighter air upwind & downwind points of sail. The only trouble is that the point of maximum draft might be too far aft on the sail for optimum performance when the boom car & clew are widely separated. A wide separation distance might also allow the leech to curl excessively to windward - good for a downwind run, bad for an upwind beat. Try it & then look up at the sail from below the boom. The point of maximum draft in the sail ought to be about 35 - 40% of the total chord distance back from the luff all the way up the sail, with no wrinkles or folds, & the leech should not be curled to windward. If the point of maximum draft is back any further than about 40% or there are any ugly wrinkles or folds, or the leech is curled to windward; then, move the boom car closer to the clew until you obtain the proper sail shape. There is probably only a limited range of boom car/clew separation distances that are of practical utility. You may find, that you can never achieve a "perfect" mainsail shape no matter where you set the boom car relative to the clew. In this case, sail shape should be the "best" possible with the boom car & clew set close together. With the loose foot, no battens, & no roach; don't be too critical of your IMF mainsail shape. There's only so much that can be done with the system & it's never going to be as efficiently shaped as the standard mainsail.

    The sail shape is most important when sailing upwind & the R-22 derives most of its upwind thrust from the big genoa. The mainsail's main function is really more to move the Center of Effort (CE) of the sailplan aft in order to balance the helm. Here, the infinite adjustability of the IMF mainsail really shines. For upwind work, you leave as much genoa unfurled as you can stand for max BHP & adjust the IMF mainsail to balance the helm. It's all very civilized & safe. It's just not very fast.

    Roger Pihlaja
    S/V Dynamic Equilibrium
    18 May 2002

    Your right about heeling slowing down the boat and that furling the headsail to much does hender performance. We're just pointing out that a 175% Genoa is a tough old sail and that the Rhodes is a tough old boat.

    When we race (me & the guys) we throw the 1st reef in the main when it starts backwinding so much that its no longer pullin. On an inland lake we can get away with not having to try for the 2nd reef (40k about top wind we have seen during a race). We keep main flat in heavy wind; Halyard tight, cunningham/downhaul, & outhaul. We try to keep it pulling and not backwinding. There is a point in there where you will just have to let it backwind but the headsail will keep pulling as long as it tight. Mainsail must be played at all times. Bill normally works the traveler continuely; full time job. We try to keep the top batten parrel with the boom as much as possible but we maintain the 20 degree heel you refer to.

    Backstays are tight with consideralbe mast bend. Healsail halyard tight and genoa sheet leads adjusted to allow a little spill at the top. We use Maylar headsails, 155% is maximun the rule allow without taking a handicapp lost. In order to keep the 155% in use, we normally will take the lost with backwinding the mainsail. If your leads are adjusted properly with the right amount of spill at the top; you can maintain speed with the mainsail being icying on the cake when it is not backwinding but I'm talking 40k here. We do keep out mainsail in play when possible.

    This will work on any boat, from the Rhodes to many others I have raced on.

    Now what some folks call tender, I call responcive. The Rhodes will respond quickly to the wind to the point that the flare hit the water. Never dump your headsail when this happens. Traveler or mainsheet will be enough to keep the boat in the groove. In heavy wind, I keep the headsail tight and pulling at all time with adjustments for heel being made thru the mainsail.

    23 Dec 2002

    Like most sailboat hull shapes, the Rhodes 22 tends to develop weather helm as it heels. Thus, in gusty, overpowered conditions, it is desirable to keep as much sail area up forward as possible in order to counteract this tendency to build weather helm. Masthead rigged boats also derive most of their thrust from the genoa, which is another reason to leave as much of the genoa flying as possible. On Dynamic Equilibrium, we will put 2 reefs in the mainsail before rolling up the 150% genoa at all. By reefing the mainsail 1st & keeping as much genoa up as possible, the Rhodes 22 will not round up until the boat heels the rudder blade clear of the water. By this point, you had better have all the opening ports dogged down tight & you may very well be taking water over the gunnel into the cockpit! However, the Rhodes 22 sails fastest when it is sailed as level as possible. It is very much like a big sailing dingy in that respect. Most of the time, heeling is controlled by playing with the mainsail's traveller. It's the most frequently used sail shaping control on the boat. However, if the traveller must be dumped to leeward more often than about once per minute in order to prevent a knockdown or a broach, then it's time to put another reef in the mainsail. By the time the boat is heeling enough to put the leeward rail goes into the water, you could be going much faster if you did something to reduce heel like dump the traveller, put more weight on the windward rail, or reduce sail area. With its big, transom hung rudder and relatively light weight, the Rhodes 22 is very responsive, especially with the latest generation sails made with composite sailcloth and full batten mainsails. The boat rewards an aggressive active style of sailing.

    The Rhodes 22 is also very sensitive to fore/aft trim. On flat water, a slightly bow down trim is faster. A slightly bow down trim allows the boat to climb its own bow wave without burying the wide flat stern section of the hull. Burying the stern section causes a great deal of drag and turbulence, rather like the lowering the flaps on an airplane wing. If the boat is on the verge of planning, a sensitive crew can actually initiate planning by carefully shifting their weight forward to slightly sink the bow & reduce the drag on the stern section. Note, that this requires a very good crew because they must also keep track of sail trim, helm control, wind shifts, their proper course, and the other boats around them. It works best with a spinnaker on a broad reach. In waves, a different strategy must be used which involves steering a slalom course among the waves, surfing down the faces of the waves and bearing off to climb the backsides. In waves, the best fore/aft trim is level with the design waterline. Trimming down by the stern is always slow & should be avoided under any conditions.

    The neat thing about the Rhodes 22 is that you can also reduce sail area & sail in passive mode under the same conditions if the crew does not feel like or does not know how to sail actively that day. It's really a remarkable little boat.

    Roger Pihlaja
    S/V Dynamic Equilibrium
    24 Dec 2002

web page developed by Logic Unlimited, Inc.