Mainsail Design Questions

[oblivionboyj]

In the course of another thread some points came up about sail design that made me curious, but rather than littler that thread with a side topic I figured I would start a new thread.

The subject of a redesigned main with added roach led me to want know what some advantages and disadvantages of certain mainsail designs are.

What are the advantages and disadvantages of:
1) A battened mainsail with no roach
2) A battened mainsail with an added roach
3) A battenless cruising sail with no roach
4) A battenless cruising sail with a roach

I am asking these questions more generically.
But if you want to know I have a Westsail 32, that I am currently not cruising in but am moving toward cruising in.
Maybe knowing that will help answer my questions.

[Snowpetrel]

1) battens arent really needed without any roach. More weight, cost and complexity, but no flogging.

2) extra efficiency and sail area. If full length battens then less flogging and prehaps better sail shape/ life, but more cost, weight and harder to lower at times due to compression on the luff.

3) easy to drop and stow, no battens to break. Less sail area and efficiency. Long leech can flutter or hook as sail ages.

4) wont work... flapping leech will drive you crazy.

Sent from my SM-G930F using Cruisers Sailing Forum mobile app

[StuM]

I don't understand your differentiating between "mainsail" and "cruising sail".

Please explain?

[Tia Bu]

Come to think of it, I've had 1, 2, and 3 above on each of my last three boats. It may be because of boat design rather than sail design- but the current boat with large roach and partial battens seems to sail fastest, and the sail is easiest to handle.

The first boat had a furling main, without roach or battens. That was the easiest to handle, but it seemed to sacrifice a lot of sailing ability, especially upwind.

My current boat (large roach, partial battens) has jiffy reefing with all lines led back to the cockpit. And it has mast slides that really let the main drop when you release the halyard. It's easy to handle, and it sails very well.

Boats 2 and 3 had lazy jacks, which are very handy, IMHO.

For what it's worth...

[roverhi]

To add to Snowpetrel's succinct summation, A full battened main will assume a proper shape but hard to alter that shape with the usual techniques, mast bend by increasing back stay tension, halyard, and Cunningham tension. Mine is easier to reef and stays bundled on the boom without the intermediate bunting ties that are needed with partial and no batten sails. Negatives are more hardware needed with more things to break. The battens add weight which means more work to raise. Not so critical for a cruiser the usually only raises the sail at the beginning of a passage and drops it on arrival. For a cruiser, a full battened main pretty much takes care of mainsail control with a vang and traveller.

Roach less sails take away sail area especially higher up which affects light air performance. Light air is where the Westsail needs all the help it can get. Wanted all the sail area I could get on our W32 with winds below 10K. Not so important in trade wind sailing as we usually sailed with a reef in those winds.

If I was to buy a new main, the argument would be between a fully battened sail or a mix of full and partial battens. If you go with partial battens, be sure the batten pocket is sewn on the sail, not just a sleeve with the sail forming one side of the pocket.

[oblivionboyj]

Originally Posted by StuM

I don't understand your differentiating between "mainsail" and "cruising sail".

Please explain?

A cruising sail is a mainsail without battens, as I understand it.
Somebody please correct me if I am wrong.
FWIW, I have never sailed with a cruising sail.
That is part of the reason I am looking for better info about which will suit me best.

[Sailmonkey]

Originally Posted by oblivionboyj

A cruising sail is a mainsail without battens, as I understand it.
Somebody please correct me if I am wrong.
FWIW, I have never sailed with a cruising sail.
That is part of the reason I am looking for better info about which will suit me best.

A mainsail is a mainsail.....be it racing or cruising. A mainsail without battens is just that, a battenless main sail.

[barnakiel]

Roach gives you more sail area compared to no roach. Roach may also make sail trim easier (think of square top mainsails).

Full battens are easier to hoist and drop, are quieter when luffing and tacking, are easier when gybing. IMHO full battened mains last better.

In a W32 I would opt for full battens with only moderate roach. Please note how your lowers run may limit you in having full lower battens.

Full batten main is also slightly more expensive - the extra gear and work is the extra cost.

b.

[oblivionboyj]

Originally Posted by Sailmonkey

A mainsail is a mainsail.....be it racing or cruising. A mainsail without battens is just that, a battenless main sail.

Yes, I am aware of that.
But the nomenclature as I have heard it isn't a "cruising mainsail".
The word mainsail is redundant.
It is a cruising sail.

You don't say Yankee headsail, or Genoa headsail, or jib headsail.
You say Yankee, Genoa, and job.
Headsail in that case, as mainsail above, is unnecessary.

[Snowpetrel]

I had a battenless main on my first boat. The thing was lovely to use, but being young and wanting more power I had the top cut off, and an extra panel added to the bottom. We put full length battens in it and a lot of roach. The extra power and speed was noticable, but it was not as easy to raise or lower as the old sail.

One big plus to the new sail was that it didnt flog, the first reef was to ease the sail until the top was luffing. In fact to windward I could completely depower by easing the sheet without the sail destroying itself as the old battenless sail would have. Made changing gears in puffy conditions in flat water real easy.

But the roachless main was a very easy sail to use.

Never heard them called a cruising sail. Usually battenless main. On a racing boat we usually had the racing main, and the cruising or delivery main. I guess that could be abbreviated to the cruising sail?

Sent from my SM-G930F using Cruisers Sailing Forum mobile app

[StuM]

Originally Posted by oblivionboyj

Yes, I am aware of that.
But the nomenclature as I have heard it isn't a "cruising mainsail".
The word mainsail is redundant.
It is a cruising sail.

You don't say Yankee headsail, or Genoa headsail, or jib headsail.
You say Yankee, Genoa, and job.
Headsail in that case, as mainsail above, is unnecessary.

Never heard that one before. Must be YART (yet another regional thing).

To me, the word "cruising" is both unnecessary and unsatisfactory. It doesn't tell me anything about the design of the sail.

I have a couple of cruising headsails and a cruising mainsail on my cat. The cruising mainsail is battened.
On the boat I race, we have a number of racing headsails and a racing mainsail.

If it hangs behind the main mast it is a mainsail. Regardless of whether it is battened or not, boomed or boomless, loose footed or boltroped, roached or not and whatever other way you want to differentiate it.

[UNCIVILIZED]

FYI, There's a lot of information on this topic in the Dashew's Cruising Encyclopedia Vol.II which you can download along with their other books, free, at www.SetSail.com

But, yes, a full batten main with lots of roach does add a lot of power, & they're more tolerant of poor trim as well. Also, having raced with them a good bit, I wouldn't necessarily agree that you give up a lot of latitude in terms of trim controls. Mast bend, & all of the others still work for altering shape, draft position, etc. Plus you can also tune the shape via how much tension is in the battens, & batten stiffness/choices. Though these latter two are hard(er) to adjust underway. However, they can also be adjusted as the sail's inherent shape changes with age. Which isn't possible with most other configurations.

One other option is a main which has full battens in the upper half, & partial length ones down low. It's a good compromise that still lets you have a lot of extra roach, with most of the perks of full battens while removing some of their drawbacks.
Plus you can usually still add full battens later on; on a whim, or to correct draft which has migrated aft with age. Thus adding life/lifespan to the sail.

I became a full batten junkie 30 years ago, & can't see going the other direction. Even a standard main with partial battens seems handicapped to me, as it gives up so much in power & trim controls. Not to mention lifespan.
Also, if you're looking at new mains, ask your sailmaker about the options of trimming off excess roach if you find that you utterly abhor it. Such may be a possibility. And you surely can't go the other way as easily.


PS: The lower heeling moment which comes with a roachy, full battened main that's well trimmed is a big perk. And a lot of "cruisers" snub that as being unimportant, like they do the same perks in new sails... until they try it.

[Sailmonkey]

Originally Posted by oblivionboyj

Yes, I am aware of that.
But the nomenclature as I have heard it isn't a "cruising mainsail".
The word mainsail is redundant.
It is a cruising sail.

You don't say Yankee headsail, or Genoa headsail, or jib headsail.
You say Yankee, Genoa, and job.
Headsail in that case, as mainsail above, is unnecessary.

That's like saying I have safety shoes.........a word, much like offshore or cruising that is thrown about so much it has lost meaning.

What can you tell me about my shoes based on the word safety? Nothing. They may or may not be steel toed, may or may not be but with electrically safe soles. Hell, they may be hip waders.

So to say I have a cruising sail is meaningless.

On out boat we have a full batten main with moderate roach. We use the boat for cruising.


Sent from my iPhone using Cruisers Sailing Forum

[Don C L]

Well, I have heard of roach-less, batten-less mains referred to as a "cruising main" (but don't ask me where) because some folks prefer them if they are primarily traveling downwind. Considering the trade-off (my boat came with a batenless main and I moved all the way to a full-battened main) I don't see the ease of handling beating out the added performance (speed + pointing ability). A fully battened main is pretty easy to handle. Also, the added roach should give you a little more weather helm to balance a big genoa for effective upwind driving. Tapered battens are nice too, but I didn't spring for them. However I'll defer to the sailmakers and naval architects as to whether light air performance is better served with full battens all the way up or partials on the bottom. I have a feeling the latter would work better for the W32.

[barnakiel]

Originally Posted by Don C L

(...)

Also, the added roach should give you a little more weather helm to balance a big genoa for effective upwind driving.

(...)

Yes.

And there is a twist.

For quite often owners going for full batten mains will specify a larger genoa at the same time.

So when it is the same genoa, the extra roach in the main will generate slight extra helm. If, in the more common scenario, a bigger genoa is used, there is another portion of helm coming from the bigger genoa alone. The two will add up (when both roach on the main and genoa % are modified).

My one comment re W32 situation is one may be limited in full lower battens - by lower shrouds layout. Pretty common limitation on boats with lower shrouds running aft at an angle. Then full top battens can be used and short lower battens (likely 2+2 on such a small sail).

Cheers,
b.