Well guys, finally a bit of discussion I can contribute to.
Swing rigs, Eric swing rigs are more efficient than standard marconi types, but not just on the run. I suspect that the difference in upwind performance that you note is related to using a simple straight yard type swing rig. The layout of this type of rig places the forward end of the yard (and hence the pivot point of the jib) to windward of the centerline of the boat (when the main section is cracked off the centerline for pointing). If then you compare the effective angle to the wind of both a standard rig and a swing rig over the centerlines of their respective boats you will find the 3+ degree disadvantage of a straight yard swing rig.
I have been developing various swing rig designs since the late '80’s, and I haven’t competed with a standard rig since. I addressed the issue of pointing angle by developing the “Breakback Swing Rig”, a swing rig with a hinged forward yard (as opposed to a forward yard locked in line with the mainboom) that allowed the jib’s leading edge to “break back” to the centerline of the boat. By lining the leading edge of the jib over the boat’s centerline this type of swing rig actually out points the classic set up of a jig with 20% of the jib boom length ahead of it’s pivot point.
On reaches a well set up swing rig should dominate a standard rigged boat. As Earl pointed out with his mention of the banning of automatic sheeting devices, getting the right relationship of the sails for reaching (which is the leg most frequently at greatest distance from the pit area) is not so easy at distance. Carrying the well tuned upwind relationship of a breakback swing rig on reaching legs is preferable because the swing rig gives one far more useful information or feedback about what is going on on the boat. With the forward yard hinged the jib reacts to minor changes in wind shifts or velocity with more sensitivity than you’ll find on a standard sail rig. A good idea is to have stripes on the jib to help in recognizing flutter. On reaches in particular the adage, “when in doubt, let them out!” couldn’t be truer, for any kind of rig, but especially on swing rigs. The rig should be let out until the jib shows just a bit of flutter, then bring the sails in one click on the transmitter stick.
Learning to read all the things that a swing rig tells you will take some patience and time on the water, there will be a lot more to sort through than what a standard rig can tell you, you just need to recognize the signs. So just handing a swing rig boat’s transmitter to another skipper is not really a fair test (that is unless the other skipper has extensive experience with swing rigged boats).
Swing rigs are very sensitive to over sheeting, they can stall if they are choked off too much. In upwind sailing the sails should be cracked off a bit every time the boat starts to slow. Sheet in when the boat has some weigh on or when the shift straightens out or strength becomes more steady. Upwind I constantly play the sails, slacking in lulls and hardening up when things straighten out. Thats sailing the boat!
I’ve outlined the concept of the break back swing rig here, but I am not the only one who has designed a working system. Jon Elmaleh and Roger Stollery in the M Class both have come up with different designs to the same end. I leave it to you tinkerers out there to work up your own versions and see if they are an improvement.
Only one rudder in the vane era M? Well, two reasons. One, the linkage between vane and rudder would be pretty hard to set up. Although, digging back into history John Lewis of the UK designed “Herald” in 1958, a twin keel/twin rudder 10 Rater. It faired poorly in light air but managed to make a lightweight boat (for its time) able to handle strong winds.
Second, in vane sailing the races are made up of rounds, and each round is divided into an upwind leg and an offwind leg called boards. The winning boats were generally the ones that sailed in a straight line, with minimal corrections to be made by the vane steering gear. Hence on vane boats like my “Sunkist” the amount of rudder area was puny compared to what I use on my r/c boats. Rudders then also were fronted by skegs to further inhibit coarse variations (in NY spade rudders weren’t commonly used for several years after the introduction of radio control). The upshot is that less radical rudder input was desirable on vane boats so two rudders wouldn’t be an experiment that would offer a solution to better performance for vane boats.
Long standing classes have vestiges of their origins because, as has been discussed earlier, new developments were permitted into the rules as long as the earlier designs were not instantly obsolete.
One other thought, long time racers like myself don’t really care too much about how a boat looks as long as we can drive it fast and are competitive with it. I think the appeal of the various archetypes in each class is a big part of the appeal and the draw that brings most of the new people into the sport (the IOM may draw a different demographic of racing enthusiasts) and into a particular class. I also bemoan the lack of interest in building boats, but it is a sign of the times. Many folks from my generation (I’m 50) and those that follow mine have little or no shop experience, so wouldn’t have a clue where to begin. The VMYG can’t reach everyone that joins the AMYA or is interested in the RG65 class with their Woodenboat School classes although I applaud their efforts at doing what they can. And, as has been pointed out, leisure time in the US has all but evaporated for those of us still in the work force, and that little time has a lot of competing demands on it. So the future for an all out development “class” is pretty bleak, development classes only work if there are some well thought out aspects that make it attractive to some segment of model yachting enthusiasts.
Thanks for that info Niel. I am very interested in making a swing rig for the RG I am building now. I am so glad that Eric got me involved with the RG class. It has been a blast to build.
Thank you for a great reply and discussion of swing rigs. Having no M fleets around here, or any other Class that uses swing rigs, we are all making this up as we go along. You are correct that the swing rigs I am experimenting with are basically inverted "T"s with a floating jib boom. So, as the main is eased the jib’s leading edge does start to project to windward. I am very interested in what a breakback rig might look like. I am imagining that the forward spar for the jib is allowed to rotate several degrees out of alignment with the main boom. Is this correct? Would it use some sort of control horn that has adjustable stays to dial in the amount it can fall off of to leeward? I can see how the sails would set up for more efficient reaching if the leading edge of the jib did not project into the path of the mainsail’s airflow.
Niel -
I concur with you and every time I see a photo of boats going to windward (even traditional rigs) with the leading edge of the jib to weather - I think the same things.
Attached is a concept idea that I was provided - probably back in late 1990’s - of a similar idea that could be used on a cat - allowing the jib to “Almost” become an asymmetrical head sail. I fooled with the idea a bit, but found my issue was with the controlling of the bottom and top wires that swung out to the side (adjusting how far out to swing). I have filed the ideas but may have to pull them out once again, and see if the adjustments can be made on water, rather than on shore. ADDED: Sorry for using a cat - but it could be used on a monohull. Thought is to manually adjust the jib “slot” for upwind work, and allow the servo for jib trim to handle the leading edge and swing out-boom. Note also that both booms were wishbone - similar to sailboard use.
I too wish to thank you for your posted response and additional detail of the swing-rig concept. Much appreciated.
I have not decided yet, but being an evaluation between two differents hull shapes, I will probably make two identical Swing rig , identical fins and rudders and then watch…
Cheers
Claudio
The forward yard is hinged, and the amount of side-to-side movement is controlled by a line from the yard to an extension of the mainboom underneath it. I let the yard fall off to the point where the leading edge of the jib lines up with the centerline of the boat when viewed from the crow’s nest. The jib boom is sheeted a bit farther out than one would trim the jib on a standard rig.
In response to Dick, the point of the breakback system is to counteract the loss of pointing angle that a straight yard type swing rig suffers from. Once you start to go much below the boat’s centerline tacking the boat becomes more difficult as you have a greater arc to pass through to head to wind and to fill on the new tack. In stronger winds it can become impossible to tack at all. My intension in developing a more advanced rig was focussed on fleet racing where swift tacking is premier, but there might be some use for the open slot system in the photo that you posted for single tack speed trials. I do think that one might have some trouble with balance with this set up but a speed trial is usually done on a beam reach so course adjustments may be all one needs to get the boat sailing without much in the way of rudder corrections.
Back to the breakback swing rig. One of the features of my rigging system is a stay-line from the aft end of the mainboom to a mast-head crane (not shown) that is under tension and controls the amount of bend in the mast. Adjusting the amount of bend in the mast will move the “pocket” in the sail forward or aft and increase or flatten the camber as required. I use fractional sails for both my M class boats and my 36/600s. In the photos the aft end of the jib boom has both an outhaul line and a leach-line. There is also a topping lift (frame stay in my lexicon) on the aft end of the jib boom that controls the twist of the sail and the shape of the slot in conjunction with the leach control line. I use the same outhaul/leach controls on the mainboom as well.
The mast is mounted to the boat in a trunk. There are a series of holes in a plate near the bottom of the trunk that engage the pin at the base of the mast. The pin passes through one of these holes and rotates on a stainless steel plate on the floor of the trunk. The top of the trunk has tracks on either side with holes through the tracks that match those in the base plate. There is a delrin plate that fits in these tracks with a hole for the mast which is slightly larger than the mast diameter. There are holes on the edges of this plate that are in line with those in the tracks but are at different intervals. This provides a vernier type adjustment for the mast location. The plate is held in place with a stainless staple which engage one set of holes in track and mast plate. This method of matching holes in the tracks with corresponding holes in the delrin mast plate gives you not only control of mast location but also of mast angle in relation to vertical.
Mast angle is very important to swing rigs, particularly in lighter winds. I rake my masts forward about 3 degrees. With the bent mast this would roughly line up the top of the rig with where the mast meets the deck when viewed from the side. Without the forward rake the weight of the mast (which is aft of the mast’s axis of rotation) would act against the rig going out in light shifts or ghosting conditions. The rig would have to be “lifted” by the wind. Raking the mast forward changes the weight distribution and tends to make the rig’s natural idle position all the way out instead of draping over the center of the boat. This is desirable as well because you can always sheet in but you can’t sheet out to force the rig out. Remember, its the swing rig’s responsiveness which is the reason for using one in the first place, if the responses are muffled then the swing rig can’t tell you what is going on on the boat.
One last thing I want to point out. Some of you may have noticed a small pin in the side of the mast just below the main fitting. This pin is used to prevent dismasting in a collision. In the delrin mast plate there is a small key hole slot in the mast hole that faces aft. To mount the mast in the trunk the rig is turned backwards facing aft so the small pin in the mast can pass through the key slot and by the mast plate. Once engaged in the right hole in the base plate at the bottom of the trunk the rig is turned forward and the sheet attached. The pin will prevent the mast from lifting out of the hole in the base plate because it no longer can line up with the key slot. Changing rigs is just the same procedure in reverse.
I hope all this is clear enough to give those rig designers out there a platform to start from. Swing rigs may take some time to tame, I know a lot of guys who’ve tried to my rigs have taped the forward yard in place to thwart the breakback, but for those who have “gotten it”, well, they tend to place pretty well. Best of luck!
I guess that I should add a note about the hinging of the forward yard. This may be self evident, but to make the hinging work, that is, to keep it from binding under load, the layout must treat the part of the rig forward of the mast like one would hang a door. The axis of the hinge must line up with the location of the jib stay’s intersection with the mast (the intersection and the fitting’s axis as the door hinges).
Swing rigs are also very sensitive to jib stay tension. Generally the jib stay should be a bit looser than on a typical standard rigged boat. In essence with the breakback, jib stay tension and jib responsiveness are in delicate balance and too much stay tension may inhibit the breakback’s ability to follow shifts.
just a point of clarification on the “cat” photos. Having and being able to keep the jib “assembly” to leeward, then tack and now hold it to weather, allows the jib to be backwinded and helps push two (or three) hulls across the eye of the wind during a tack. One can tack a multihull with a conventional rig/jib setup, but it takes more concentration and as the wind increases, so does the tendency to weathervane - especially in boats that have little or no lead for momentum to carry them through a tack. Obvioiusly a separate jib servo would accomplish the same thing, and also allow (while sailing) separate jib trim relative to the main sail and its angle of attack, much like a real boat. Now with the costs of servos coming down, and also multi-channel radios, the back-winded tacking has been pretty much addressed. Your thoughts about speed trials are right on. Remember, this concept came up in the late 1990’s - long before the cost efficencies of the new multi-channel radios we now have available.
As a follow-up to my original “out-loud” question - and NOT a reflection on the specific class example I used, I post the following that I will watch with great interest. It “seems” the boys on big boats also were looking for a method to develop and present new ideas, and this California based race has added a new twist to encourage new ideas to be demonstrated AND raced. WOW - imagine that - folks younger than 65 years (or 50 years) old, actually building boats using new ideas, construction methods, technology - and actually having a venue in which to present their efforts! Some will no doubt opt for following a specific class or size, while others ??? well it remains to be seen. Regardless of the outcome, my hat is off and kudos to the event sponsors and promoters. Perhaps, with interest, this event may replace the old OOAK (One Of A Kind) and NAMSA (North American Multihull Sailing Association) regattas for development ideas to be presented and raced.
From “Sailing Anarchy” website ( copyright to SA and the event promoters) the following “seems” to emulate what I had originally tossed out for discussion and ideas.
" The Border Run International Sailing Event has some big changes in store for racers in 2010. The most newsworthy are a new and more convenient start date and the advent of a new exciting Shadow Boat Class. The Shadow Boat Class is for experimental designs that, ordinarily would not fit the criteria for most coastal races, will sail with ‘Shadow Boats’ for safety and video coverage. “There’s simply nothing like it in the US. The Shadow Class will add an exciting ingredient to an already great event while offering designers and racers a venue to promote new designs for the future. More boats means a better event for everyone.” said Border Run co-founder and designer Randy Reynolds" from Sailing Anarchy
Depending on results of this big-boat event, this could be a possible “invitation only” future regatta for developmental ideas in r/c yacht racing, perhaps coupled with a long-ago proposed “speed trial” for r/c yacht classes. Again, something to stimulate “positive” thought and ideas.
