Masteheaded Vs Fractional rig

A simple 'Masthead vrs Fractional' debate is really too simplistic without reference to all the other variables that are involved. If you constrain some of the these, such as for a given sail area, or mast height, or cost, or boat speed, or ease of use or structural strength, the 'best' rig advice might well vary.

For instance, if you were going to do a lot of trade wind sailing, then there are specific issues that may well influence what rig would be best: If you fancied twin poled out headsails, then a mast head rig might be preferred as you could set a larger running rig. Also, the common use of swept back spreaders with fractional rig can also lead to loads of wear and tear off the wind, but some people find running backs a pain, but the alternative diamond stays seem to have fallen from fashion of late. However the smaller spinnaker on fractional rigs can be easier to handle when short handed and fractional rig boats generally can manage a wider range of wind speeds (and angles) with fewer headsails, or cope better with a roller furling headsail.

Your Tartan 30 is very similar to our old S&S on which I have covered tens of thousand of offshore miles. They were both children of the seventies whose fine upstanding mothers were inseminated, (probably against their will) by the sperm of the IOR devil. The rig rated well but was never designed for ease of handling or outright speed. However it's not all bad news as in the 30ft size things are still manageable and the slippery hull moves well.

But they are headsail driven. Any dreams you may have of only using non over lapping headsails in winds much less than 20kts will be frustrating at best. The most versatile headsail will be a 135 percent, fairly high clewed genoa, similar to the No2's of old. On the wind, you will be able to carry this into the 20's but will lose power much below 10 kts. We carried a 155 light No1, but frequently augmented the 135 with a bit of engine, rather than do a headsail change, unless we were certain conditions would be light for some time.

Our next smaller headsail was a full hoist 100 percent solent jib, that would take us up wind in the trades, or to snug us down a bit at night with winds in the high teens. It had a set of reef points that would quickly allow us to shorten it by about 30 percent of area in squalls. After that it was a proper storm jib. Most sailing was with the 135, and today set on a roller, I still think it would be your most useful sail. But if heading for the trades, I may well still take a full hoist 100 that also fitted the roller. However, I think I would carry more diesel than the 155.

The other bad news about the 70's IOR boats is they need spinakers to move off the wind. The mainsail again is not really big enough to give much power, and the genoas twist off and do diddly. The original racing chutes were huge, driven by the boats long J measurement. However they were what we had and with a well rehearsed system were usable singlehanded by me and the girlfriend without any trouble. However if I was putting together the ideal system I would carry a .5oz conventional spinaker and a 1.5oz cruising chute for running in heavier airs with the tack on the stem and the clew poled out, or reaching set without the pole. The 135 with its higher cut clew also poles out well, and when the self steering struggled as the boat got skittish in about 25kts of wind, a reef in the main balanced her up, which defies all logic as the 135 was already significantly bigger than the main.

It's these sort of idiosyncrasies that you have to explore with boats. The simple models about weather helm aren't always that helpful. Our boat never carried any weather or lee helm despite radically different sail combinations. But her balanced waterlines, did mean she didn't have much stability in her 'stern quarters' and hull speed when deep running could be a bit rosy. But plenty of main boom vang to keep the leech bar tight stopped it getting out of hand (too often).

People may say that's a lot of sails and different combinations. But I'm afraid that's the legacy of that damn rule. Certainly a well sorted modern cruising specific rig, either fractional or masthead, would be easier, but go with what you've got rather than sit at home dreaming of the ideal.

But I actually thought at the time it was a very reserved wardrobe. We had been campaigning an IOR 2 tonner at the height of their 'development'. We wouldn't have left the dock without (if I remember) a Drifter, Heavy No1, Medium No1, Blast Reacher, No2, Solent No3, No4, Storm Jib, .5oz floater, .75oz radial head, 1.5oz cross cut, .2oz storm chute, blooper, heavy blooper, mainsail and trisail. I can't work out if I miss that lot more, or stainless steel wire halyards. Now they were a really good idea! Not.

 

Cay:

Your explicit post answered my question. Thanks. Like many have said, is a whole package issue, not simply a matter of changing one factor. I never intended to modify athe rig,, anyway, and your explanations on the origins, make perfect sense...

Thanks a lot!!

 

Masthead rig downwind

 

Well stated

Thanks for that one, the specifics are indeed very important in this discussion.

 

Single-masted Ketch

Have you ever seen this 'cutter rig' combined with a mizzen, and no mainsail??
http://www.runningtideyachts.com/sail/

 

Fractional rig--Raggi Thor

Oh-boy,,,,does that ring some bells.

A little digression, but, it seems as thought using the back stay as a main flattener on a masthead rig is not ideal (more stress on the rig & hull, pumping, and or inversion) and you really need a flatter cut main to carry more mainsail in higher winds?
(ie more sails)

 

Roly,

What you do is to crank/jack/winch on the backstay until the mast overbends from the compression load, then you use the checkstays to pull the middle of the mast back to your desired amount of bend, that will give you really nice headstay tension.

Yoke.

 

Thanks for the explanation, yoke.
My boat has only fixed lowers;No checkstays.
And my mast is symetrically oval with no taper. Old.
My over exuberance on the backstay probably contributed to my current rebuild.

 

As with much of engineering, it was a materials problem.
Stainless steel doesn't stretch much. These days we have very hi-tech synthetic lines, but back in the mid 1970's and 1980's the lines were more stretchy.
Most of the ones I dealt with had a line spliced to the SS wire so that you
handled the line most of the time.

As far as huge overlapping genoas: my understanding was that they were there to
create an aerodynamic slot and increase efficiency (as mentioned above;
like a multi segmented airfoil).

I sail (well, own anyway) a San Juan 24, and am used to the wire halyards.
Here on Puget Sound, the 170 Genoa is great for going to weather in light air.
The boat's biggest weakness is downwind in heavy air (death roll).

I crewed on a Synergy 1000 for awhile, and it's a very different type of sailing.

And somewhere between the two lies the Santa Cruz 27, which will be my next boat
if I ever find time to go sailing.

Or an Olsen 30 if I can get my accountant to approve it

Ultimately, they are all fun in different ways. If speed were the only factor
I would go to a multi hull with a rigid wing.

 

Yes they were stainless steel halyards with rope tails, but the wire over the sheave, work hardened under load. Although we had four genoa halyards rigged we broke them all in one 650 mile off shore race. After that they were replaced with galvanised and we never had any trouble again.

 

Roly,

I wouldn't want to be without an adjustable backstay, since that is what you use to adjust the overall the overall power to suit conditions. Most importantly, restrict how much you can ease the backstay and not break it with the lowers, assuming the lowers are set a bit aft of the mast. At some point, additional tension will bend the boat but not straighten the forestay anymore, that is your max tension, don't exceed it.

A sailboat is designed to handle its rigging loads, provided its decently built, I wouldn't worry about maxing the backstay when conditions warrants it.

For your type of rig you want to set backstay, (headstay, really) depth, twist and halyard in the jib and match the main settings to the median wind and then shed the puffs by feathering and/or easing the mainsheet enough to keep the boat feeling good and fast. If the wind is trending up or down, you adjust the other controls to suit. When the wind is steady or you have plenty of people-power, playing the backstay together with the mainsheet is fast.

This might seem excessive to some, but for me, sailing on a poorly trimmed boat is a dreadful experience.

Yoke.

 

"Yes they were stainless steel halyards with rope tails, but the wire over the sheave, work hardened under load."

With a bit of work perhaps you could rig halyard locks as used (usually) on much smaller boats.

A ball is siezed onto the wire and the sail is hoisted till it locks, and luff tension is put on at the foot.

To lower the sail its simply hoisted an extra 2 inches where it frees from the lock.

This effort will reduce mast compression by 1/2 , perhaps worthwhile to the "edge of the envelope" racers.

Even better for the window shaderoller jib folks as they almost never can hoise a straight luff.
A downhaul to a sheet winch is fast & EZ.

Actually built a forestay toggle with the halyard lock built in , bit couldnt find a market.



FAST FRED

 

On mast bending in masthead forestayed (forestaid?) rigs...
On some boats (Santa Cruz 27, San Juan 24, et. al.)
they use a babystay to either fix the position of the middle of
the mast so that bending is in the upper portion, or on some
they can adjust the tension in the babystay to pull the middle
of the mast forward (dependent upon class rules).

 

Mast position

Hello,
Can anyone explain me why the mast is not as the same position for a masthead configuration and a fractionnal one? ( as written in http://www.rcryachts.com/fractional.htm). Is it only a problem of center of effort position or is there any other issue?

kimper

 

You're right the first time. It's mostly a matter of center of effort. The keel, because it also serves as ballast, has to be under the middle of the boat, or under the boats center of boyancy. Because the jib on a fractional rig is smaller than the main, the Center of Area ends up further aft.

So, to make the rig ballance with the boat, you have to move the whole thing forward. And, if you don't want to mess with a bow sprit, this has to be done at the expense of the jib sail area, making it even smaller in proportion to the main.

Bob