carbon fiber mast

[mastreb]

Here's an idea for you mike:

Instead of having a track or channel at all, put a vertical roller furler in place just abaft the mast. this is a standard roller furler such as the type that already comes with the genoa. It's mounted at the masthead using the same strap-hound used to mount the forestay hound with a jaw-jaw swivel shackle and a turning block for the main halyard, and terminates at the mast foot (don't worry about the gooseneck for now). The standoff distance from the roller furler stay to the mast is just barely enough to roll up the mainsail, which is constructed with a thin kevlar belt at the mast foot instead of a bold rope so it will roll up thin.

Proper tension is maintained by the halyard which probably ought to be on a rope clutch mounted to the mast before its led aft. In most cases, this halyard can simply be set and forgotten, since the main and mast will now come down as a unit.

At the mast foot, the entire mast sits on a piece of strong aluminum square extrusion that is 3" wide by perhaps 4" tall and perhaps 6" long. The extrusion is hollow and open athwartship (i.e, you can see through it from port to starboard). This extrusion bolts directly onto the current mast foot of the MacGregor. The mast stands atop it, with the forward edge of the mast aligned with the forward edge of the extrusion. The extrusion protrudes aft past the mast extrusion perhaps 3", and is drilled on top just abaft the mast to allow the roller furler shaft to come down inside the extrusion. The furling drum sits inside the extrusion, and extends out beyond the extrusion on the port and starboard sides.

The furler line is then led out the side of the furler to a turning block mounted nearby.

By putting the drum directly below the mast at the mast foot, we can keep the roller furler close to the mast and in the aerodynamic flow of the mast but still use an inexpensive already existing furling unit. The furling line can be winched using the cabin top winches as well.

This gives you furling, reefing, and solves your mast track problem all for less money than a mast track would likely cost. Furthermore, the extrusion can be bolted in the same way as the current mast foot so as to retain mast rotation capability--the entire furler foot rotates with the mast. Finally, a strong through-bolt is installed inside the extrusion just forward of the drum which serves the purpose of transmitting the mast compression force from the actual mast through the extrusion to the actual mast foot, so the compressive force is not on the aluminum extrusion but on the hinged mast foot--just as it is with the current rotating mast, just with a longer bolt.

Use an aluminum boom with a track slot for the loose-footed mainsail as this is low to the deck and won't affect righting moment much. The gooseneck is just an over-sized hound on the mast which goes around the rotating shaft of the mainsail roller furler and is affixed to the mast with a through-bolt as a hound normally would be. The hound allows for up/down movement of the boom. The boom has a forward endcap with a vertical bold that holds it to the hound while allowing side-to-side movement, with little or no fore-aft movement.

Actually, now that I think about it, this mainsail furling unit could just as easily be mounted on the existing aluminum mast.

There are two options for trailering:

Dissassembly (one person method).

1) Furl the mainsail and remove the outhaul line from any cleats or clutches on the boom.
2) Unbolt the boom hound from the mast. Remove the boom and stow.
3) At the mast foot, unpin the roller furling shaft from the drum collar. Most furlers are built with a permanent bolt here--we replace it with a pin, cleaves or just a longer nylock bolt for disassembly.
4) Using the halyard, pull the mainsail up slightly to remove the shaft. Then with the foot in hand, walk back to the cabin as you loose the halyard and lay the mainsail down on deck. Unshackle the mainsail when the peak is down and secure the halyard to he mast.
5) Lower the mast as per usual.

Quick (two person method).

1) Furl the mainsail.
2) Lift the boom vertical and tie it to the mast/mainsail with the outhaul.
3) Lower the mast. when the mast comes down to he mast bracket, have the second person hold it instead.
4) Unpin the mast at the foot, and walk the mast forward to the pulpit while the second person supports and passes the mast/mainsail without letting it roll on the mast bracket.
5) when the mast is in place, pin the foot. Rotate the mast assembly sideways so that the mast does not sit on the mainsail. Wrap the mainsail in a towel or other thick cloth to prevent its chafing against any part of the mast bracket.

Anyway, would be interesting and shouldn't be a difficult build. Would require a custom mainsail, but roller furling always does.

[Ixneigh]

Why not just glass a track made out of PVC or something onto the mast? If you oiled up the shoulders with mold release you could probably slide the track off, if it ever needed to be replaced.
Not thrilled with the furler idea, since it seems like the weight advantage, already smallish, would go away with any type of drum, swivel or extra cable. I guess you could use dyneema though. Plus don't furled mains like that have crappy shape when deeply reefed?
Ix

[ecossebob]

Great idea, especially for us older guys.
How about a drawing to clarify the system. Especially the new base extrusion and how the furler drum mounts. How would you attach the furler swivel at the mast head?. You said this could be installed on the existing mast, how about your thoughts on that?.
Why would you need a new main sail?, I thought the 26M mast was straight.
By the way I got the bends out of the mast and splicing it together as soon as I get the splice. That's why I am intrigued as I'm hoping to make my 26X into a 26XM
Thanks again Bob.

[mastreb]

Why not just glass a track made out of PVC or something onto the mast? If you oiled up the shoulders with mold release you could probably slide the track off, if it ever needed to be replaced.
Not thrilled with the furler idea, since it seems like the weight advantage, already smallish, would go away with any type of drum, swivel or extra cable. I guess you could use dyneema though. Plus don't furled mains like that have crappy shape when deeply reefed?
Ix

Furets don't weigh much more than a sail along the length of the sail, all the furler and drum weight is at the mast foot, where it doesn't matter at all because it's not aloft. Everything you can do to lower the weight on the mast should be done. Otherwise, for weight above the foot, it should be a wash compared to a glassed-on track because it consists of nothing more than a steel cable and a furler sleeve.

Yes, the shape of the furled sail abaft the mast is not 100% ideal, but if you're furling then you already have more wind than you need, and efficiency is no longer a concern at all. The only result will be slightly more heel than would have been the case with a perfectly aerodynamic sail under furling. As long as the _unfurled_ sail is efficient, which it can be with a piece of custom shaped plastic extrusion as the furling shaft, then there's no practical negative impact. Where it becomes a problem is if there's not enough halyard tension and the sail leaves the mast airfoil.

Bob the reason you'd either need a new sail or some modification is to eliminate the bolt rope in the food, which will be too large when furled. Removing the bolt-rope and stitching on a strip re-inforcing flat canvas would do the trick however. You'll also want a Sunbrella stripe.

I've got a roller-furling mainsail on my new boat, and I love it. I'll never have another boat without it, and if I wind up keeping the Mac or acquiring another in the future, It will have a roller furling mainsail come hull or high-water.

By the way, I saw an image of a simple roller reefing gooseneck that MacGregor used on older ventures as a stock part that I thought was a great idea: The gooseneck is attached to the mast by a through-bolt rather than rivets, and it has a tang going town about six inches that is thumb-screwed to the mast. To reef the mainsail onto the boom, you simply unscrew the tang, rotate the entire gooseneck about the through-bolt, and then re-bolt the gooseneck once you've got the reef you want. Sure, you lose the Vang when you reef, but that's a small price to pay--plus you can always just slab reef if you don't want to lose the vang. Still ideal for furling at the dock and by un-bolting the through-bolt you can remove the sail, boom, and gooseneck completely for trailering.

I'm not sure why they ever went away from that simple system.