so I am doing some work on my rigging. What are the pro's and con's of a loose-foot vs the standard sail setup? I am concerned that the loose foot would put too much stress on the boom. ON that line, is most of the stress on the boom (in either case) going to be horizontal, or vertical (which way should I orient the rectangular boom?)? I am wondering, since I am going to secure the boom in a manner similar to the gaff, and it is easier to install the jaws in one direction.
Robert,
I'm using a 2X3 Quartersawn Doug Fir boom instead of the round stair rail approach. I did so for a number of reasons but primarily for the additional weight which helps to maintain sail shape and secondly so that I could use a loose footed main with a track mounted outhaul at the aft end of the boom. I also recommend the use a traveller to help with boom control.
In sailing in a whole lot of varied conditions in various Weekenders over the last 5 years I've come to the conclusion that I like the loose footed main for its ability to work both upwind and down wind with greater control of the sail shape.
In sailing with Capt. Jake and his Weekender "Fire Escape", we've played a lot with fine tuning sail shape and tension as well as minor adjustments in rigging to make it perform at near optimal levels for light to moderate wind conditions in protected waters of South Puget Sound. The leech line on the main sail is used extensively to help shape the main for the conditions as well as adjusting the tension on the outhaul to give us good light wind and down wind performance and then to flatten the sail to work upwind.
Same with the lapper and its leech line.
It does no good however to use a standard foot on the main and use it loose footed. The main has to have a significant roach sewn into it along with some camber to the lower portion of the sail and a leech line to control tension on the leech of the sail.
In most cases when working in light air, the main will bag out and fill better with the foot staying below the boom level until the wind freshens substantially, then it will raise to just about even with the boom and really grabs the wind with a strong pulling power.
Regardless of how I've worked with a standard mainsail with laced foot or unlaced foot, I've not been able to accomplish the same thing. It will work loosefooted but to no real advantage over being laced. In fact it works better laced to the boom than being loose. The foot has to be controlled in the standard cut main to function well. The only way that can happen is to have it laced to the boom with an outhaul to adjust tension to some degree.
I've not had the opportunity however to go side to side with two boats with stock on one and loose footed main on the other. So my observations are pretty objective and based upon small changes and trimming to get things working well. But once you get a feel for it, the advantages in my mind are well worth having a well cut loose footed main that is right for your conditions and local.
It takes a number of considerations to make a loose footed design work for it and they are all covered pretty well in The Sailmakers Apprentice. Well worth checking it out from the library on intra-library loan if not available in your own system.
Combine a well designed and sewn loose footed main and a good lapper and you have a well balanced sail plan with a lot of flexability to work in the majority of light to moderate wind and water condtions. Then it is simply a process of learning the conbinations and waching the tell tails to shape the sails and trust your sensies of the changes happening when you make them.
Loose footed mains need to be cut as a loose footed sail. In other words you can make an attached foot sail loose footed, but the performance and shape will suffer. An attached foot sail needs to stay attached, a loose footed sail needs to remain loose footed. It's a function of the way the sail is constructed, literally the shape of the sail is very different in the lower 1/3rd between the two different styles.
A loose footed boom will experience more point loading, so it needs to be stronger to resist excessive flexing. An attached foot boom works primarily in compression, with the twisting and flexing loads spread reasonably uniformly along its length. Because of this, the attached foot boom can be of smaller dimension.
In light winds the loose foot main will generate more drive then the attached foot mainsail. This is because the shape of the sail isn't changed much along 2/3's of its height. Attached foot mains work better in heavier winds, when the sail starts shaking and tossing out wind because of sea conditions.
In the wind strengths these boats are used, a loose footed main will have an advantage over attached, but it's a small advantage. On a race course with two identical boats, it would make a difference, but in real life, not a noticeable one to the average sailor. Personally, I like the loose footed look and control issues, better then attached.
However, a standard main is easier to adjust the outhaul on if the entire foot is not lashed to the boom. I lash my main about half way out the boom which keeps it snug and does not load up the pressure points, but makes it much easier to work the outhaul than having the entire foot of the main lashed to the boom. Not to mention it is easier to take the sail on and off.
well, I guess in this case I will go with the stock dimensions, and lashing, see how I like it, and change it later if I don't.
My boom is also 2" x 3", anyone think it will be a problem if the 2" side is vertical when installed? (It will be easier to attach the jaws) As long as the sail doesn't pull up too much more than sideways, I figured it would be fine.