Kites are suspiciously like spinnakers, which also work well, but carry a significant safety disadvantage. You can't stop in a hurry and go back. Fun, but not always easy to deploy or demount.
I have been mulling over this ever since I first decided to have a junk rig. The one thing which I have always thought is miserable about the junk rig is having lower camber (and often heavier cloth) in the upper panels, against the small percentage of time spent sailing in heavy conditions. Its quite the wrong way round. The storm sail should be at the bottom, not at the top.
Its like wearing a raincoat everywhere you go, even on nice days – just in case it rains. The paradigm should be that you always have a raincoat to hand, but wear light clothes most of the time and only put the raincoat on if it rains.
(I’m talking about in-shore sailing here, where most of the time you can choose your weather. The ocean cruising paradigm has dominated cruising boat design in New Zealand, to the point of spoiling it).
So, my idea is that a junk sail should be built for light to moderate weather, with the top panel always intended to be an effective topsail. In ultra light conditions, especially the long fine periods of summer we have here, the mast itself could be raised to an extra height of one panel (a five-minute job) and an extra bottom panel, which is normally carried in reef configuration, simply comes into play.
The complications are not that great. Serendipity already has an extendable mast, though at present it is deployed permanently in the raised position. The mast is in a sunk tabernacle (which extends down to the keel, and protrudes above the deck, giving about twice the amount of bury which would be required). You can think of the tabernacle as a telescopic lower mast extension, with two positions.
The tabernacle is an aluminium top-hat section, weldless, and folded from a single sheet, thicker than the walls of the mast. Quick and simple. The heel of the mast is built up to be square and is a sliding fit in the tabernacle. At the “partners” (the top of the tabernacle) is a two-part clamp made of cast, heavy duty rubber. It fits the mast and fits inside the tabernacle. The bolts holding the gates of the tabernacle can be slackened slightly if necessary to allow the mast to slide, and the raising can be done by a vertical cable attached to the heel and shortened by a hand winch of the type used by trailer boats, mounted at the top of the tabernacle. When the mast is in the raised position, its weight is supported by a removeable dummy section. I think the idea will be transferable to a larger mast. I have already made a 11m mast with a folded aluminium tabernacle to match, with square heel and cast rubber partner clamps, but have not yet tried it in practice.
(I would not expect it to be 100% watertight at the deck, but very nearly so, and any drips can be confined to the inside of the tabernacle and a sump in the bilge, and taken care of by evaporation)
The other complication is that the lifts need to be semi-running. When the mast is raised, the lifts need to be adjusted to a second position, to drop the bundle back to its normal place. (Running lifts also allow the bundle to be dropped into a stow position, in gallows).
For storm conditions – I am still thinking about this. I have been thinking perhaps a storm sail could be carried in the sail catcher, with its own yard, ready for deployment. It it might be permanently attached to the boom (in which case it would be a simple matter of unclipping and swapping the halyard over and hoisting it, while the normal sail remains furled in the sail catcher. They could share the same boom, and I think the sheeting system will work on the boom only. But this allows only a single panel storm sail – like a try sail.
I would prefer a low-slung, heavy-duty low-camber proper heavy weather sail with, say, 3 panels, which lives in the sail catcher, ready to be deployed, with its own yard and battens. This might require not only swapping the halyard over, but also an instantly demountable sheeting system of its own, similar to what Serendipity has now. Swapping sheeting systems is an extra complication I have not yet figured out. It is certainly easy enough to do, demounting by a quick-release fitting at the "horse" - but it would require care stowing and unstowing the sheeting system with its pesky sheetlets, especially in turbulent conditions, and may be potentially a bad idea. (Currently I am learning how to carefully stow the sheeting system together with the sail, inside the sail-catcher, as I stow and unstow it each time the boat is used, being a trailer boat.) Clipping on a storm sail at about the third batten, and using the existing sheeting system, would be better – not yet fully figured out.
But the principle is to have an extendable fine weather rig, with the storm system being a clip-on – rather than a rig set up permanently for bad weather, with a clip-on light-weather extra.
I think the above idea is perfectly feasible for a SJR with its concomitant sail catcher, and is less complicated and less compromised as a sail, than some kind of topmast extension with a clip-on topsail.
PS Jan - That's right. The low-yard-angle sail, with its requirement for a taller mast, does give you a "wasted" naked area at the top which cries out for a light-weight extra. I suppose all that would be required is a clip fitting at the tack and the clew of this colourful tops'l, so it can be clipped to the yard - and its own dedicated light-weight halyard (the burgee halyard?). You'd drop the sail, clip the tops'l on on, then hoist both. If the mast is already extra tall, like Amiina's, that would be fun to try, with nothing to lose. Dead simple. I'm guessing something like this is what Slieve has in mind. Your idea is good because it does not require a running topmast (the anthithesis of KISS).
Merry Christmas.