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grumpy old man
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I don't know why not. But a loose footed main needs to built to be loose footed. You can't just take a regular main and fly it loose footed. The shape in the foot would be wrong. My own loose footed main had roach in the foot and it dropped below the boom. Often times there is a short, vertcal batten in the foot to support this roach.
 

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That is how I sail my dinghy. Seems like it gives sail a better shape.
 

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For best results I think at least the old bolt rope foot (and any 'shelf') should be cut off, but as BP indicated you won't have that wee bit of roach in the foot unless the sailmaker adds it.
 

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I agree with Bob. The basic shape of a sail is sewn into it by the sailmaker. My general practice is to use something in the way it was designed to be used, unless I'm sure that using it differently will work better. A sail with an attached foot is designed to be attached to the boom along the foot. The end plate effect captures the air that flows across that part of the sail and keeps it from spilling off the foot. I'm not sure, because I'm not a sailmaker, but I think the foot of a loose footed mainsail might be a few inches longer, and that the few inches of extra length might help keep the air from spilling off the foot of the sail. In any case, unless you know, or have good reason to believe that it will work better by flying it loose, I'd fly it attached.

The advantage, in terms of sail shape, that you get from a loose footed mainsail is that you can create a much deeper draft in the foot by easing the outhaul. Attaching the sail to the boom limits the depth that you can create in the foot. Before the advent of the loose footed mainsail, the only way you could get a really deep foot was if you had a shelf-footed mainsail, and you usually only saw those on racing yachts. The loose footed mainsail lets you create a similarly deep foot as the old shelf footed racing sails, but, as discussed above, I'm not sure you gain anything by flying an attached footed sail loose at the foot.

If you gain any advantage at all, I'm reasonably sure that the sail will only work better, if at all, in light air, where a deeper foot might help. So, I'd suggest that you normally fly your sail with the foot attached in moderate or stronger winds. In light air, you might experiment by flying the sail loose footed, and see if it helps.
 

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For best results I think at least the old bolt rope foot (and any 'shelf') should be cut off, but as BP indicated you won't have that wee bit of roach in the foot unless the sailmaker adds it.
..... and woven (dacron) TAPE added to the edge of the foot section, to replace the 'strength' function of the boltrope.

With the typical height of a boom from 'the deck', a large added foot roach isnt going to amount to much improvement.

Id do this in 'steps' and leave the original 'shelf foot' and just remove the boltrope but add edge 'tape' to return the foot back the original strength. Then, if the shelf foot causes shape problems when the sail is used loose footed, then recut the foot and replace/add a new lower panel. A shelf foot usually is cut substantially as a long 'curve' into the first bottom panel of a cross-cut sail and removing the shelf foot would create a 'hollow'/concave shape to the foot.

As a first step simply leave all alone, simply dont insert the slugs/boltrope and fly it loose footed "as-is".

Do add a 'clew slug' when flying any sail loose footed: http://www.sailrite.com/Slug-Coated-Outhaul-15-32#.UtQHRnm3uHM
 

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grumpy old man
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One thing to keep in mind if you make this change:
The attachment of the foot of the main to the boom spreads the loads of the main out along the boom. With a loose footed main the loads are all at the tack and the clew. This means that if you have mid boom sheeting you can be putting a big bending moment on the middle of the boom (picture a bow and arrtow) Ideally for a loose footed main the mainsheet would come from the clew. Ideally.
 

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Discussion Starter · #10 ·
Lot's of great info already!

I was contemplating this as I find the slot for the foot on the boom is tight and makes adjusting the outhaul difficult. I don't have any mechanical advantage with the current OEM setup and was hoping to gain some flexibility without re-cutting the sail.

ETA:
Bob, it is mid-boom sheeting in my case.
 

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grumpy old man
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Weinie:
Ok, then I woud keep a weather eye on just how much you are bending the boom when you are strapped in and on the wind. I'm sure some bend won't hurt. Is it single point sheeting or are there two or three blocks on the boom. That would help spread the load out.
 

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a. That the foot suports that boom is old myth. All of the signifigant load is on the clew or the foot would logically be flat as a board.

b. You are not going to be able to stretch the foot without a winch or sustancial multi-part tackle, unless you remove the footrope and recut. Can you get the outhaul to a mast winch? Perhaps that was the original intent. Really grunt on it and it should flatten.
 

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Tartan 27' owner
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Lot's of great info already!

I was contemplating this as I find the slot for the foot on the boom is tight and makes adjusting the outhaul difficult.
This was a huge difference for us when we went with a new loose footed main. The outhaul was so much easier to use as there was no friction from a bolt rope. Shaping the sail for varying wind conditions is so much easier now. We also have end boom sheeting and mechanical advantage on the outhaul.

Suggest you rig up some kind of mech. advantage for your outhaul. Even 2:1 is better than nothing.
 

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grumpy old man
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I had neither multiple purchase on my outhaul or a winch for it. I had no trouble getting the tension I needed if I did it when the sail was not loaded. I always had a can of McLube on hand.

The foot of a main attached to the boom IS as flat as a board. Unless you have a Park Ave boom. That's why a loose footed main is better. That's the whole pint with loose footed mains and shelf type mains. The loose foot allows the natural foil shape of the main to continue down past the boom much like the foot of a jib.

Find the thread here called "What's going on in this pic" and you will see what happens to the foot of a jib when it is laced to a "boom" much lke a mainsail would be. It's flat as a board at the foot. Not good.
 

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On my last boat I sailed lose footed for a few years, then put a track on. Zero difference. My current boat has been sailing loose footed on the main for 29 years and several Pacific crossings. No problems. As Bob pointed out ,keep an eye on the bend . I have a stiff boom with the sheet point at the second reef point, to minimize bending, either with full main, or reefed . It doesn't bend in any visible way. My main is a used sail ,made for use with slides and track. No problem. My lazy bag is under the main, with far less problem than it would be with slides. My lazy bag is my water catchment at sea, with no holes for slides needed.
 

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I noticed a huge change, like some previous posters, when I switched to a loose footed main. Boat was faster, and sail was easier to shape.

I can't see any harm in taking the boat out in light to moderate wind, sailing with the foot in the slot, then pulling it out and loose-footing it. you may want to purchase a single slug that fits the bolt rope slot and lash it loosely to the clew, so you can adjust sail shape easily while trying the loose footedness. (sure, it's a word...look it up.)

A properly cut loose-foot sail will certainly perform better, but you can get a good sense of whether or not you like it using the sail you've got!!

Andy
 

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grumpy old man
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aelkin:
I agree with you. But BS uses used and very worn out sails on his boat. It figures that he would see no difference. IF a loose footed main was NOT more efficient, why does every performance oriented boat today have a loose footed main?

There may be reasons not to have a loose footed main, particularily for cruisers, but the reasons do not include performance.
 

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........ you may want to purchase a single slug that fits the bolt rope slot and lash it loosely to the clew, so you can adjust sail shape easily while trying the loose footedness. (sure, it's a word...look it up.)
A clew strap works as well, and doesn't need to be 'slid out' of the slot when you take the sail off..
 

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aelkin:
I agree with you. But BS uses used and very worn out sails on his boat. It figures that he would see no difference. IF a loose footed main was NOT more efficient, why does every performance oriented boat today have a loose footed main?

There may be reasons not to have a loose footed main, particularily for cruisers, but the reasons do not include performance.
Bob, I raced with an (attached) shelf footed racing mainsail for many years before the advent of loose footed mainsails, and never saw a significant difference in terms of speed or pointing ability, except in light air. My boat, with a shelf footed mainsail, was every bit as competitive against loose footed racing mainsails as it had been before they appeared on the racing scene. If you think about it in terms of basic sail trimming principles, the reasons will be clear.

If you think about it, when either a mainsail with an attached foot, or one with a loose foot is trimmed to beat to windward in 10-12 kts of wind, the shape of both sails is virtually the same. The ideal depth and position of the draft is about the same for both sails, because the characteristic behavior of the wind at that speed is what dictates the ideal shape of the sail. Thus, there is no significant difference in the performance of both sails in winds of 10-12 kts and higher.

A loose footed mainsail can only do one thing significantly different and better than an attached footed mainsail. In the past, most mainsails had a standard, shallow draft foot. They didn't have a deep racing shelf foot. Because an attached foot sail is attached to the boom, when you ease the outhaul, the depth of the draft that you can achieve with that type of sail is limited, because the attachments won't let the sailcloth float freely. But, a loose footed mainsail isn't attached to the boom, so, the more you ease the outhaul, the deeper you can make the draft. That is the primary advantage that a loose footed mainsail has over one with an attached foot. The only time when it is beneficial to create a deep draft in the mainsail is when you want to power it up, such as in light air, or when sailing deep downwind. Thus, the only time when the loose footed mainsail has an advantage is when you want to power up in light air and when sailing deep downwind. (My old shelf footed racing mainsail was as fast as a loose footed mainsail on every point of sail, because it was capable of being shaped just as deeply in light air as a loose footed mainsail.)

As you know, lots of people sail for many years without ever adjusting their outhaul. When they buy a new sail with a loose foot, they see how the wind shapes it, and it suddenly occurs to them that they can improve it's shape by adjusting the outhaul for different windspeeds. They often become better, smarter sail trimmers, but not because the sail is inherently faster. They become better, smarter sail trimmers because the loose foot enables them to see some characteristics of sail shape and sail behavior that they never noticed or thought about very much before.

To answer your question, Bob, every performance oriented boat nowadays has a loose footed mainsail for a variety of reasons. First, because that's what the sailmakers will make for you, unless you specify that you want a mainsail with an attached foot; and also, because it's easier for a sailmaker to make a loose footed sail than one with an attached foot; and also, just because there's no good reason that I can see why a boat owner should insist on using a mainsail with an attached foot. While they're not inferior to a loose footed sail, except in very light air, they also aren't superior in any way, either. For that reason, my thinking is that, if you have a good quality mainsail with an attached foot that is still in good condition, keep using it, and don't cut it up in the hope that it will make it faster, because you'll be disappointed.

A new, loose footed mainsail isn't going to perform significantly better, except in very light air, and then it will only help if you know how to trim the boat and sails for light air. I spend every summer trimming the sails on high performance racing boats, and, while their sails provide far superior performance in many ways, it isn't because of their loose foot. When I replaced my old mainsail, I specified a loose foot, but not because I thought it would perform any better. I specified it simply because I couldn't think of a good reason why I shouldn't.

I'm not alone in my opinion. In an article written by Dan Dickison and published by FX Sails, he concludes: "Neither concept offers a significant performance advantage under sail for most types of boats, but the loose-footed approach can provide significant advantages from a maintenance and equipment handling standpoint." Loose Foot vs. Attached Mainsail
 

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Sailormon6 presents some very good points about the functional differences between the two types.

There is a small difference that is notable - dimensional stability over time in favor of the shelf foot. The purpose of the boltrope is to prevent overstretching of the sail material due to wind forces and overzealous tension on the outhaul; overstretching promotes slippage of the individual fibers; and if done too many times with too much force, the foot dimension will 'grow'. The boltrope helps prevent that permanent 'over-stretching' or 'creep'.
Its VERY easy to overstretch a loose foot dacron sail and if done often enough the sail will develop a permanent 'girt' or horizontal crease close to and parallel to the boom as well as permanent deformation/'creep'.

With boltroped sails, that boltrope is cut a wee bit shorter than the 'hoisted' dimension (by about 1" shorter for every 10-11ft. of foot or luff length) and it does takes extra force to get the boltroped sail to its 'as designed' dimensions and 'as designed' shape. Not a big deal if you use multi-blocked tensioning systems or a winch. A shelf and boltroped footed sail is going to keep its shape a LOT longer than a loose foot .... and more importantly will keep it shape more consistently in varying wind strength during the day's sail ... that boltrope is what better controls the 'stretch'. In comparison of the two types, a loose foot will more easily change its amount of draft especially in the lower panels during major changes of wind strength.
 
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