What is advantage of loose footed main sail?

[LANCE ON CLOUD NINE]

Could anyone please comment on the pros/cons of a loose footed mainsail? I am currently sailing an O'Day 23 that has sails in pretty decent shape, but my instincts are that I am not maximizing horsepower from my traditional mainsail. Could I get any more power by having it loose on boom and shaped more like a jib? Any other thoughts on how to best rig sails on this particular boat? It has about a 120% roller jenny that I can usually leave completely open. RichH if you have time, I would really appreciate your thoughts. Thanks to everybody! Lance

 

[Tim R.]

Better shape

You generally can achieve better sail shape(read more hp) with a loose footed main. But you should talk to a local sailmaker. Tim R.

 

[DannyS]

Not necessary

I just put an order in for a new mainsail from UK Sails and I asked the same question. I was told that a footed main was a result of a racing rule that filtered down to cruisers. From what I understand, the rule has since been changed and therefore, the loose footed main is becoming the norm. A loose footed main holds its shape better and in fact, my sailmaker stated that he has not made a footed main in several years except for one and it was for someone who liked letting his grandchildren hang out in the "hammock" created by the boom and the footed main.

 

[s sauer]

Loose Footed Main

A loose footed main is easier and faster to trim-- that's the main benefit.There is no more 'power' unless you increase it's size and Roach and then don't mind the battens possibly hanging up on the topping lift and/or backstay.If you are racing, I'd go for a loose footed main, a full top batten and the remaining battens extra lenght "IOR" battens -- no PHRF penalty.Full battens are moere of a cruising option and add more weight aloft but may make it harder to shape the main in light air.Now how about your jib/ Genoa which is the real 'horsepower' on a masthead rig.Could you carry a larger Genoa? Would you want a 155% for lighter air?Can you drop the 120 out of the furler and hoist a 155% on that foil?Do you have a shoal or deep draft keel? What are the wind speeds in which you typicaly race. For a deep keel boat in light air a 155% may be right; if winds are always in the high teens and up, your 120 may be perfect and you'd might get a higher rating with it(lower PHRF numbers being the boat is expected to be faster with the larger headsail).There are other improvements to be made to a masthead rigged boat; it's controls, boom vang, cunningham, backstay adjuster, etc; but the size of the main is limited. However; If your interest is not racing, forget most of this and look into an asymetrical cruising chute.

 

[RichH]

Easier to control the shape of a loose footed sail.

A bolt-roped (slugged foot) mainsail is constructed with a 'shelf foot' in an attempt to 'smooth the curve' of the transition between the area of maximum draft at the bottom section of the sail and the attachment to the boom (slugs). The shelf foot cannot be pulled as taught with the outhaul as can be done with a loose footed sail therefore the amount of maximum draft that one can 'flatten' in a shelf-footed sail is limited. The loose foot can be pulled 'as flat as a sheet of plywood' with the outhaul; therefore the loose foot has MORE adjustability, can be flattened instead of reefed (to the first reef). The foot edge of a loose foot is constructed of sail 'tape', the foot of a shelf fooot is constructed with a 3 strand dacron rope inside of a sleeve .... the more the 3 strand is stressed the more it will change dimension (shrink) over time ... and therefore needs to be 'adjusted' periodicallly (or the sail will become 'baggy' in shape. The loose foot is easier to shape, can be flown in higher wind strengths without being reefed because it responds much better to the outhaul tension (flattened). A shelf footed sail is a very obsolete design since the advent of a loosefoot has been allowed to have a 'foot apron' .... a bit of sail that can 'hang' lower than the bottom of the boom (racing rules).

 

[Warren Milberg]

When I was buying my main

for my H28.5 from North Sails a few years, the guy I dealt with was pretty candid about the real or imagined differences in shelf-footed vs loose-footed mains. He felt that the primary advantage of the loose-footed main was the ease of bending it on and off, an easy chore I do twice a year. He also indicated that the loose-footed sail required less labor to make and it sold for the same amount as the shelf-footed sail, so the profit margin was a bit greater. Having sailed for years with shelf-footed mains, I bought that style for my current boat and have never regretted it. I believe I can harden the outhaul to flatten this sail in a blow about as easily and quickly, and get the sail just a flat (or, if the wind is light, to increase draft) as if it were loose footed. In the end, the loft thought is was just a matter of which style you happened to like better.

 

[LANCE ON CLOUD NINE]

Thanks to everyone for your answers

I am a fairly laid back cruiser who just knows enough to know that I have lots to learn. I am just getting to the point where I want to tweek the boat beyond the obvious. I will put your info to good use and pass it on when I can. That's the beauty of this site! Lance

 

[KevinB]

Flattening reef points

The footed main should have been built with flattening reef points to help flatten the sail by pulling in the shelf area when the wind picks up. But it is obvious that tightening the outhaul when the wind picks up is faster and easier than having to set the flattening reef points, so score one for the loose foot.If you look at the Laser, which dates back to about 1972, it had a loose footed main. It makes you wonder why keel boats took so long to catch up; could it be that until the '60s it was quite common to use roller reefing booms, which may have been easier to control with a footed sail.

 

[RichH]

You're probably right, Kevin

A shelf foot is a royal PITA to roll up on the old fashioned boom roller reefing; plus the shelf foot alway produced wierd wrinkles when rolled. I perceive the real reason (especially for woven dacron sails) is the propensity of that 3 strand foot boltrope (necessary for a shelf foot sail) to continually shrink - thus continually forcing deep draft or requiring constant adjustment by a sailmaker to be the main reason for most folks to abandon the shelf foot. (I used to have to 'ease' or readjust my boltropes after about 50-75 hours of hard racing or the sail would have too much draft develop). Flattening reefs are REAL old technology and dont result in the flattening of the lower panels as well nor as fast because of the relative complexity (two control lines instead of one) in comparison to a loose foot. When racing to put in a flattening reef reduces sail area; with a loose foot you can still have the same sail area and can make the sail almost as flat as sheet of plywood if necessary --- then its easy to 'blade-out' the sail (by 'playing' the traveller) when necessary and still have ALL the sail area up and useful for the 'lulls'.

 

[carina]

What about boom bend for mid boom sheeting?

Anybody worry about the bend of the boom if your boom is mid-sheeting. Does the foot bolt rope provide any load distribution along the boom.Is this an issue for someone considering a loose footed mail.I sail my h27 (midboom sheeting) with the boltrope out and yes it does shape better, especially if I want to let it out. I observe the boom bending, not much really though and I've been in some strong winds on the Columbia. The h27 is tender though and reefing early helps the issue.Hugh