Ideal sails for Cutter rig. 130% headsail + 100% staysail?

[Dockhead]

Wow, thanks for NOT letting it go, Greg!


That's a lot to chew on, and definitely shows how little I know about this. Very interesting.


First time I ever heard that a cutter works better to weather than a sloop. I always heard and understood that a cutter on the contrary has more drag and therefore is WORSE to weather than a sloop.


What is the truth here? All I can say is that my own experience does not contradict what Greg has written. I have some challenges trimming my self-tacking staysail, but with a bit of barber hauling I will get more drive with the staysail in use, hard on the wind, and certainly this cutter performs much better upwind than my previous sloop, but that's not apples to apples because this boat has a bulb keel and higher aspect rig.


I can also say that now that I have vertical battens and a straight luff, I get a lot of drive from the mainsail, with or without any or either headsail up, and I can sail the same angles upwind with the main alone, as I can with the whole sail plan.


Not that those angles are very impressive, but still.



Hmmm.

[Dockhead]

Another question for Greg:


You wrote: "Looking at our cruising mains with moderate roach, the lower aft sailcloth is providing very little lift to weather - lift happens mostly in the front third or so of the airfoil. So let's cut that off."

I presume this would be true of headsails as well?


If so, then why do we even have overlapping headsails at all?


I have two principle headsails -- a non-overlapping blade jib, and a 120% yankee. I spent a ton of money on the carbon laminate yankee which however spends its life in a bag and in the way, because the conditions where it provides more drive than the blade seem to be extremely few, basically only really light wind and even in really light wind only with the wind abaft the beam. Even in really light wind, the much smaller blade seems to provide more drive upwind!


I always suspected that I was doing something wrong with the yankee. It seems to need to be trimmed looser than the main, which I seem to need to slightly overtrim for the yankee to work properly, and the whole rig seems to stop working at about 30 or even 32 degrees apparent, whereas the blade is still pulling strong at that angle.

[jt11791]

Originally Posted by Dockhead

Wow, thanks for NOT letting it go, Greg!


That's a lot to chew on, and definitely shows how little I know about this. Very interesting.


First time I ever heard that a cutter works better to weather than a sloop. I always heard and understood that a cutter on the contrary has more drag and therefore is WORSE to weather than a sloop.

Sure, that's why you see so many cutter rigs winning races .

[CarinaPDX]

Originally Posted by Dockhead

You wrote: "Looking at our cruising mains with moderate roach, the lower aft sailcloth is providing very little lift to weather - lift happens mostly in the front third or so of the airfoil. So let's cut that off."

I presume this would be true of headsails as well?


If so, then why do we even have overlapping headsails at all?


I have two principle headsails -- a non-overlapping blade jib, and a 120% yankee. I spent a ton of money on the carbon laminate yankee which however spends its life in a bag and in the way, because the conditions where it provides more drive than the blade seem to be extremely few, basically only really light wind and even in really light wind only with the wind abaft the beam. Even in really light wind, the much smaller blade seems to provide more drive upwind!


I always suspected that I was doing something wrong with the yankee. It seems to need to be trimmed looser than the main, which I seem to need to slightly overtrim for the yankee to work properly, and the whole rig seems to stop working at about 30 or even 32 degrees apparent, whereas the blade is still pulling strong at that angle.

Sail cross-sections are essentially airfoils, and a decent airfoil has most of the lift centered at about 1/4 or so aft of the leading edge. This applies to all sails, to windward, when the wind is coming from in front of the sail (downwind is different). Extending a sail aft does provide more lift, just less efficiently, but it also adds to the healing moment. In light air you are looking for every bit of lift and you can stand up to the sail. In stronger winds the narrower sail is needed to reduce healing, and just like a main a taller, narrower headsail will have more lift than a shorter, longer sail with the same area (but also have more healing moment due to higher CE).

The reason you want lapping headsails is to help create the "slot effect". The flow of air off the front of the jib continues along the back of the stays'l, and the air off the front of the stays'l continues along the back of the main, all in a continuous laminar flow (mostly). They work together to get more lift. Drop the staysail and with a blade you lose some of that effect. You want the sails to be close enough to interact with each other. And you don't want the headsail sheeted in so tight as to close off the slot.

I don't understand why your yankee is performing poorly. Certainly it should do better than the blade if it isn't too much canvas, the balance is maintained, and it is trimmed right. If it was too much sail forward then you would expect to have a lee helm, which you shouldn't allow to happen anyway. If you can you might arrange for your sailmaker to go out with you and see what is happening. From here it is just speculation. And odd.

30 to 32 degrees? I can't even imagine; Carina's full keel isn't providing that sort of lift.

I have done a lot of reading over the years, taken a class in fluid dynamics, and taught a very technical sailing class for several years, but trust the pros. A good sailmaker is a good friend to have...

Greg

[TheThunderbird]

I dont follow this interest for speed.
These are cruising boats.
Practicality, ease of use , not much heeling, cost, durability, are most important.

So, why having overlaps?

[Dockhead]

Originally Posted by CarinaPDX

Sail cross-sections are essentially airfoils, and a decent airfoil has most of the lift centered at about 1/4 or so aft of the leading edge. This applies to all sails, to windward, when the wind is coming from in front of the sail (downwind is different). Extending a sail aft does provide more lift, just less efficiently, but it also adds to the healing moment. In light air you are looking for every bit of lift and you can stand up to the sail. In stronger winds the narrower sail is needed to reduce healing, and just like a main a taller, narrower headsail will have more lift than a shorter, longer sail with the same area (but also have more healing moment due to higher CE).

The reason you want lapping headsails is to help create the "slot effect". The flow of air off the front of the jib continues along the back of the stays'l, and the air off the front of the stays'l continues along the back of the main, all in a continuous laminar flow (mostly). They work together to get more lift. Drop the staysail and with a blade you lose some of that effect. You want the sails to be close enough to interact with each other. And you don't want the headsail sheeted in so tight as to close off the slot.

I don't understand why your yankee is performing poorly. Certainly it should do better than the blade if it isn't too much canvas, the balance is maintained, and it is trimmed right. If it was too much sail forward then you would expect to have a lee helm, which you shouldn't allow to happen anyway. If you can you might arrange for your sailmaker to go out with you and see what is happening. From here it is just speculation. And odd.

30 to 32 degrees? I can't even imagine; Carina's full keel isn't providing that sort of lift.

I have done a lot of reading over the years, taken a class in fluid dynamics, and taught a very technical sailing class for several years, but trust the pros. A good sailmaker is a good friend to have...

Greg

OK, I'll talk to my sailmaker, who is a very knowledgeable guy -- makes a majority of the sails used in Cowes Week, in fact!


I do not have any balance issue; my boat, totally different from the old one, is indifferent to sail plan balance. Weather helm is a linear function of heel angle. So I can use headsail alone, main alone, any combination of reefed/unreefed sails, and I still have exactly the same rudder angle at the corresponding heel angle, and just the right rudder angle so long as heel is not more than about 15 degrees.

[Dockhead]

Originally Posted by TheThunderbird

I dont follow this interest for speed.
These are cruising boats.
Practicality, ease of use , not much heeling, cost, durability, are most important.

So, why having overlaps?

Well, speed is FUN. Don't we sail primarily because sailing is fun? What's better than having every sail trimmed just right, pulling at its full potential, and scudding across the water? Why just the LOOK of well trimmed sails is pleasurable.



To each his own, I guess, but just bobbing around like a tub with baggy rags up doesn't appeal to me at all. I have target speeds for every set of conditions and an accurate log, and I work on sail trim. It is fascinating and complex, and gives me a great deal of enjoyment. I learn something significant every single year, although I've been at it for decades.



And fast passage speeds are nothing to sneeze at, either, especially if you cover long distances like I do every year.

[jmh2002]

Plus speed gives you weather, safety, time, and comfort options, as well as the possibility not to use it, by reducing sail.

It's easier to make a fast boat slower, but difficult to make a slow boat faster.

Personally I don't follow this interest of for going slower than necessary, unless there is a special need for it.

[Dockhead]

Originally Posted by jmh2002

. . . .as well as the possibility not to use it, by reducing sail.

Amen! If you don't for some reason want your 9 knots or whatever, just reduce sail and glide along with zero heel and zero effort -- it's lovely.


While passing all the heavy tubs heeled over and struggling under a mighty spread of canvas to make 7, or whatever . ..

Originally Posted by jmh2002

.It's easier to make a fast boat slower, but difficult to make a slow boat faster.. . .

Ain't that the truth!

[jmh2002]

Originally Posted by Dockhead

Amen! If you don't for some reason want your 9 knots or whatever, just reduce sail and glide along with zero heel and zero effort -- it's lovely.

While passing all the heavy tubs heeled over and struggling under a mighty spread of canvas to make 7, or whatever . ..

[CarinaPDX]

Originally Posted by Dockhead

OK, I'll talk to my sailmaker, who is a very knowledgeable guy -- makes a majority of the sails used in Cowes Week, in fact!


I do not have any balance issue; my boat, totally different from the old one, is indifferent to sail plan balance. Weather helm is a linear function of heel angle. So I can use headsail alone, main alone, any combination of reefed/unreefed sails, and I still have exactly the same rudder angle at the corresponding heel angle, and just the right rudder angle so long as heel is not more than about 15 degrees.

I had my working sails (main, yankee, stays'l) replaced while in Cowes - still have them. I suspect he is no longer there after 20 years though. IIRC he was a Ratsey but it was not a Ratsey & Lapthorn loft.

You have a very strange boat Sail balance has a significant effect on my full keel lead mine. Moving the CE fore and aft relative to CLR has to change the torque and thus affect steering - are you running on rails? Strange. Of course the healing causing weather helm is to be expected, and extreme heal can even result in an uncontrolled rounding up for many boats.

This whole thing about speed is kind of amusing. If one is in a hurry why travel at 7 knots, or 8, or whatever? Take a jetliner at 500 knots. OTOH a great part of the enjoyment is in trimming things just right and seeing the boat do its thing - a combination of pride in mastery and pleasure at the result. It has been said that if there are two sailboats going in the same direction there is a race, and I have to admit to trying just a little harder when being paced by another boat.

Greg

[Dockhead]

Originally Posted by CarinaPDX

. . . You have a very strange boat Sail balance has a significant effect on my full keel lead mine. Moving the CE fore and aft relative to CLR has to change the torque and thus affect steering - are you running on rails? Strange. Of course the healing causing weather helm is to be expected, and extreme heal can even result in an uncontrolled rounding up for many boats.. .

I thought it was very strange myself. All my previous boats have been very sensitive to sail plan balance. This one doesn't feel it whatsoever. Perhaps it's because the sails are much higher aspect, so the CE of main and jib are close together.


Or maybe the hull design. Wherever it comes from, this is one of the things I like best about this boat. Just enough helm to keep the rudder over a few degrees producing lift, and it's always just enough, unless I let her get overpowered.

[Don C L]

Originally Posted by Jim Cate

Hi Greg,

Some race handicap systems have indeed led designs down silly paths, and IMO, the big foresail and small main plan is one of them. If you have been following various threads related to the subject here on CF, you should have noted a number of folks who have found that replacing big genoas with blade (~100%) jibs have improved performance all around, except in very light airs. A particularly adamant proponent of this plan is Dockhead, who posts on the subject frequently.

And I again would like to point out the development classes, where there are no rules other than limits on total sail area, and where fractional rigs with small jibs have proven to be the fastest compromise over many years of development. Yes, these are racing dinghies, not cruising boats, but the aerodynamics are the same in general, and they are not operating in the wild speed realms of AC boats or even fast keel boats.

There is another advantage to big main plans: they sail well on the main alone, something that my previous boat with its IOR plan just would not do very well. This can be a very useful feature for a cruiser, eg tacking slowly into an anchorage with good visibility and the ability to depower rapidly as one drops the anchor.

Any how, that's how I see it!

Jim

I am one who fell for the 50 year old glossy photos of enormous sculpted 180 genoas overlapping the main, assuming this was the best, even for upwind. IN fact my old boat did really well, ON A REACH, with the 150 and one reef in the main. But now my new boat, and some valuable discussions here, have taught me the error of my ways. Hardly used my genoa at all last summer even on a reach.... could it be all I ever needed was a drifter and a regular old 'working' jib? And my oversized old school main all by itself gets a workout just as Jim describes too...
just young and gullible I guess....

[wingssail]

Originally Posted by Sebastien972

Thank you for the replies everyone.

So for information about the boat, it is a 1980 Choate 40.

And here are some pictures of an identical boat with a similar rigging except that mine doesn't have the furler on the head stay and the forestay sail is a cable.

https://imgur.com/a/TzuEM5z

You have a late 70's design IOR boat. This boat will perform best with a large genoa or a blade headsail. It was not designed as a cutter or to be sailed with a yankee and a staysail. This is an upwind boat which will perform very well with small sails. It is not a fast offwind boat.

Personally I would sail that boat with a 100% bladé headsail (full hoist/deck sweeper). I would change sails to a 120% genoa on light air days. This boat will be a rocket upwind in 20kts with a full main and a blade. It will ghost high and fast on a light wind day with a big genoa. The close chainplates mean you can sheet into about 8 degrees from the centerline, AND STILL GO!

If your staysail is big enough you can use the staysail on it's own stay instead changing headsails but be aware that if the staysail is much less than 85% of the foretriangle area it will be useful only in heavy winds.

I have a somewhat similar boat and we use either an 85% jib or a 120% genoa. for racing we have bigger sails available.

The mainsail is important on this boat. You can change gears by using a blade headsail and reefing up or down as the wind increases or decreases. With a good blade headsail you can cover a range between 10 knots of wind to over 30 just by reefing.

Over that you can drop the headsail entirely and sail with just the main.

Have fun with the great boat, just don't expect it to be a full keel cutter.

[wingssail]

Originally Posted by Jim Cate

Hi Greg,

Some race handicap systems have indeed led designs down silly paths, and IMO, the big foresail and small main plan is one of them. If you have been following various threads related to the subject here on CF, you should have noted a number of folks who have found that replacing big genoas with blade (~100%) jibs have improved performance all around, except in very light airs. A particularly adamant proponent of this plan is Dockhead, who posts on the subject frequently.

And I again would like to point out the development classes, where there are no rules other than limits on total sail area, and where fractional rigs with small jibs have proven to be the fastest compromise over many years of development. Yes, these are racing dinghies, not cruising boats, but the aerodynamics are the same in general, and they are not operating in the wild speed realms of AC boats or even fast keel boats.

There is another advantage to big main plans: they sail well on the main alone, something that my previous boat with its IOR plan just would not do very well. This can be a very useful feature for a cruiser, eg tacking slowly into an anchorage with good visibility and the ability to depower rapidly as one drops the anchor.

Any how, that's how I see it!

Jim

Our IOR design boat sails excellently with solely mainsail, we do the anchorage sailing thing you mentioned often. We often also sail in higher winds with just a reefed mainsail. The main is a big contributor to our sail plan. In fact the main/blade combination makes a great sailboat.

OP's Choate is a classic, late design, IOR. It will perform best with a full sized main and a smaller jib, or with a full sized main and a large genoa.