aluminum mast question

[wscherf]

I am currently building Arch Davis' Ace 14, a simple ply-on-frame daysailor. He calls out a wooden mast, but I plan to go with aluminum because I am lazy. Have also done the wooden mast on my Stornoway 16 (actually the rig from Ian Oughtred's Fulmar), and am not in love with it. Big yard is a pain to deal with when dousing the rig. Reefing is no fun.

I plan on using Dwyer's DM-2 section, with a fixed gooseneck, and slugs that ride in the groove rather than a boltrope. How far above the boom connection should the opening for the slugs be, and how big an opening does one need?

Would also like to try making the sails for this critter, although I don't think that I have any particular sewing talent. My friends need something to laugh at. Thought I'd go with a Sail Rite kit. Is it possible to botch up something like this so badly that it would be unusable? I have no illusions about producing professional quality merchandise.

[Wild Wassa]

I feel about 15-16 cm is the absolute minimum with 20-22 cm conveniently realistic where as 30 cm is too far for some bottom slugs. A smaller distance than 15-16 cm would be finger pinching and not allow you to comfortably feed the slugs into the track if the boom is on the mast when the tack is secured. The real issue is the height of the bottom slug above the foot.

Also when lowering the main will you have a pin engaged in the bottom of the sail track so that it stops the slugs from leaving the track?

If you rig the boat on the trailer, then lower the main and then drive to the ramp and need to leave the ramp quickly, think this one out, if you are single handing the boat? A pin holding the slugs in the track is very useful when returning to the boat and hoisting the sail.

What takes up the slack in the luff just the main halyard? Can a cunningham be employed?

If you are using a cunningham, will the lowest slug be removed from the sail track when pulling down at the height that you choose?

These are issue that affect one of the boats that I crew on that uses slugs. The lowest slug is not well positioned so we have to lace the bottom of the sail through the cunningham eyes (the sail has two) around the mast a few times to stop the sail from losing shape, because the second slug is somewhat up the mast. We have one advantage over what you have described for your boat, that is the goose kneck is on a sliding track so that we can lock off the boom at different heights ... then there is no minimum distance.

Possibly this variation is worth thinking about.

Warren.

[Todd Bradshaw]

With a fixed gooseneck, the most critical aspect is to get the shape of the sail's tack corner and the boom connection to work together properly. This involves what's called a "tack setback" on the sail. There will be some sort of eye or fitting on the gooseneck that the sail's tack ring is supposed to attach to. It can be anywhere from 1/2" to several inches aft of the back side of the mast, depending on the gooseneck design. The tack setback means that you cut the corner of the sail back so that the tack ring is back where it needs to be to meet the gooseneck fitting. Get it wrong and the entire tack area and lower luff of the sail sets poorly with big wrinkles.

Here is a sail with a tack setback. It has hoops around the mast instead of slugs, but the idea is the same. The setback is that jog in the luff at the corner to align the tack ring with the boom fitting.
http://www.imagestation.com/picture/sraid48/p1a52d5510f3a1750c9b0131ce59d442d/fcb9d7e5.jpg

Here is one with slugs. It's a small setback distance on this one because the gooseneck fitting is very close to the mast, but there is a slight setback.
http://www.imagestation.com/picture/sraid28/pc146694cd88712b151fe44373be10e45/fd6829f7.jpg

That's part one. Part two deals with the slugs. You want the first slug on the normal (vertical) part of the luff just above the spot where the setback cutaway begins (as shown in the photo or where the bottom hoop is on the drawing). Obviously, that slug isn't going to do much good if it happens to fall at the spot where you have cut a hole in the mast slot for feeding the slugs in. So you need to cut the slot either above or below the height of that first slug (both can work - sometimes one method is favored). Slugs are normally spaced about 26" apart with two slugs close together (4" or so) at the top. Adjustments to the slug spacing can be made as needed if you need to move a slug a bit due to a batten or reefed configuration. The length of the hole in the slot itself isn't terribly critical if the sail and mast are designed to fit each other. 4"-6" or so is pretty common - usually enough to fit the two slugs on the headboard in at the same time when you first start feeding the sail into the groove.

The best thing is often to get a big hunk of paper and make a full-sized drawing of the tack/gooseneck area with accurate dimensions to be sure that the tack setback, first slug placement and feeder hole location all work together properly. You can build the sail to fit an existing gooseneck or the gooseneck to fit an existing sail, but any way you do it, they need to be made to fit each other.