Fractional Rig vs. Mast Head Rig

[Jeff_H]

Bob,

I saw that it was a quote, but simply because it is a quote doesn't make it right, at least without some kind of context. On the face of it it runs counter to any reality that I know of. It would be helpful to the discussion if you can perhaps provide a synopsis of where Peter Hahne's coming from.

Respectfully,
Jeff

[bob chaisson]

OK……., I just wanted to toss in a simple quote, it seemed like you fractional fans were having a field day beating on the masthead rig and that just struck me as very one sided and maybe at bit closed minded. Keep in mind, your dragging me into this debate against my will but I’m easy, so I’ll oblige. From an engineering standpoint, I personally like having a big steel cable tied to the tip of my mast and the butt of my boat, it just gives me a warm and fuzzy. Oh yea, and just for the record, my masthead rig does not have forward lower shrouds. But anyway, to the point. The professional opinion that I quoted substantiates thusly. "The masthead rig has a number of practical advantages, the main one being that it is easy to work with. It’s undeniable that it only offers a limited range of sail trim possibilities but the big advantage right from the start is that it is easy to set up and tune." At this point he details tuning a masthead and then tuning a fractional. I don’t think anyone will dispute that tuning a fractional is significantly more complex. Additionally, while under sail, maintaining trim on a fractional rig involves greater effort. We have already the deficits of running backstays ie. they require almost constant attention, but," If you have a fractional rig without running backstays, the upper shrouds should be set up tight. This will transmit tension into the forestay. However, you will have no way of adjusting it while sailing or be able to alter the profile of the (headsail) to suit the prevailing conditions. On a masthead rig, the tension on the forestay is only controlled by the backstay. Again, the tension on the backstay, and thus also on the forestay should be less if the wind is free and light and a choppy sea disturbs the set of sails. A slack backstay and consequently slack forestay will help make the headsail profile deeper and thus more powerful." As to angled spreaders, "It’s harder to control the profile of the mainsail accurately than with running backstays. Even with angled spreaders, the tension on the forestay decreases with increasing mast bend. A rig like this has to be set up really tight in the first place to achieve good results when sailing upwind. The mainsail is the fractional rigs primary driving force. Upwind you must control the profile of the main with considerable care. Otherwise, the sail plan’s center of effort will move too far forward and might result in lee helm." Anyway, that’s enough of that. If you want more, buy the damn book, it’s only 20 bucks. Then you to can argue the virtues of a masthead rig.
But seriously though, glad I could add some enlightenment. Never sailed a masthead rig and had no opinion until this post. Never could resist supporting the underdog. Just bought the book and haven’t even finished reading it. The guy makes a hell of a lot of sense though, so I thought his input might be worth mentioning. Thanks for all the info in this thread, I’ve learned a lot from it.
You actually made me go back and study the book (this is a good thing).

[Faster]

Originally Posted by bob chaisson

OK……., I just wanted to toss in a simple quote, ..... From an engineering standpoint, I personally like having a big steel cable tied to the tip of my mast and the butt of my boat, it just gives me a warm and fuzzy.

Bob

Nobody here has been advocating the recent trend to backstay-less rigs, and (other than dinghies and recent Hunters) relatively few frac rigs don't have a real backstay.

Granted there are some losses re headsail shape, esp in a situation without runners, but the gyst of the percieved "advantage" is in reduced headsail size ( jibs gennies AND kites) for a more easily controlled boat with minimal crew.

Those of us running fracs without runners pay the performance price as a trade off for the ease and convenience. Anybody doing this is obviously not racing, and on this board racers appear to be minority.

Having owned both types up to 40 feet, I am now pleased to have a fractional rig for the reasons stated previously in this now-revived thread.

Given the large numbers of existing masthead rigs in boats generally 10 years old or older, they are here to stay, and they sail just fine. But these days, given the choice and all other things being equal, I'm glad to handle the smaller headsails and have good control of the most powerful sail, the main.

[sailingdog]

Corsair trimarans don't have a backstay.

[Jeff_H]

Thanks Bob, the additional quotes give me a sense of where Hahne is coming from. Which isn't to say that I aree with him. I think his quote predate advances in rig design and the typical increased complexity of a modern masthead rig somwhat antiquate that poistion.

I would agree that designing a modern fractional rig is a bit more complex but the result of a good design is a fractional rig that is easier to tune and sail than masthead, which is why these days the majority of modern designs have fractional rigs. For that matter, historically the majority of rigs were fractional rigs before the racing rules of the late 1950's changed that.

There are couple things that have happened since the late 1990's that have also somewhat reduced the complexity of designing a fractional rig relative to a masthead rig. Since that time almost all manufacturers of modern boats have gone to multiple spreader rigs and tapered rigs whether a frac of masthead. Computer aided design programs for spar design and for sail shaping have become better and become the norm. Sailmakers have learned how to design sails for the higher headstay sag and mast bend typical of a fractional rig.

These days most leading edge raceboats and high quality coastal cruisers. as well as many offshore cruisers have fractional rigs, and few of these have running backstays. And with better computer designed sails, little if any performance is sacrificed on these running backstay less fractional riggers.

Respectfully,
Jeff

[Plumper]

Originally Posted by sailingdog

Corsair trimarans don't have a backstay.

As I understand it, trimarans have different demands than monohulls when it comes to rigs. The wide base they sit on allows them to run fixed backs to the amas at such a wide stance that a backstay isn't needed. If they are fast they also never have the wind astern so they don't need to be able to let the main out as far as a monohull does when running. Many also have rotating masts which affect rig design sinificantly.

[JohnRPollard]

Bob,

Thanks for your input. Hahne certainly makes some valid arguments.

I don't think anyone here is bashing masthead rigs. Most of us that own somewhat older designs from the 1970's 80's, and 90's are sailing masthead rig boats. I personally own one and am immensely pleased with the sailing performance of our boat.

I've also sailed extensively on fractional rig boats, one of which was equipped with runners. For the kind of sailing we do, I would never want another boat that relied on runners to keep the rig up. (Although our current boat requires runners for sailing in heavy weather under cutter rig, that is a rare inconvenience I can live with).

But that is not to say I'm blind to some of the advantages of and recent improvements to fractional rigs. Most notably, modern fractional rigs for cruising boats rarely require the use of running backstays. I think I mentioned earlier in this thread that my ideal dream boat would be fractionally rigged, primarily to simplify sailhandling (it would also have a sprit with a masthead Code 0 or gennaker-type sail, but that's another thread.) In the meanwhile, I'll be happily sailing along in our very capable masthead rig.