I have yet to test out my leeboard design -- as I've been land bound due primarily to a recent bout of ill health -- but I'm hopeful that the design -- drop-in and pull out -- will work as intended. I can also locate the leeboard any where along the gunwales to suit the balance of the sail and prevailing conditions.
My leeboard is a recycled waterski.
I know my sail design works -- but I want to extend its surface area by running it aft further by extending its mast so that it carries the sail almost the length of the craft ( if I'm lucky I may manage 12 feet, give or take 'issues' ).
The bilateral sponsons/outriggers also serve their purpose. And in case I do heel over too much, and capsize, I'm exploring ways to add buoyancy by adding floatation foam to the gunwales.
It's still early days in bringing this all together and I'll be experimenting and adapting the design features but for now I'm interested in finding a way to furl and unfurl the sail while more or less seated . Previously I used a rope and tossed it over the mast a few times to wrap and unwrap the sail. But in this setup I need to have a system I can rely on to work effectively and fast without requiring me to stand up to operate it.
I like being forced to do the homework to answer my own question and the last post got me going:
Considering reefing a proa sail -- and mine is in like mode -- Proafile has this to say:
Pacific Islanders apparently never reefed. There are no reef points in traditional Oceanic lateen sails. Instead, the Oceanic sailors developed a system of brails or "spilling lines". These are two lines that are tied on about 3/4th of the way out along the boom. They are then run on each side of the sail through deadeyes or blocks located on the mast top, and then down to deck, where they are either hand-held or cleated, depending on wind conditions. These lines serve several purposes; They act as a topping lift. They function like lazyjacks to keep the yard and sailcloth under control when hoisting or lowering the yard. They allow the sail to be de-powered or quickly furled by lifting the boom up close to the yard. By manipulating the lines individually, huge changes in sail drive can be had without any reduction in sail area. If the leeward brail is tightened, it produces a "crease" in the belly of the sail, sharply reducing lift much in the manner of flattening a western sail. Things get even more interesting if the windward brail is tightened. Efficient lift requires a relatively flat sail. By tightening the windward brail, the sailcloth is forced into a very deep curve, effectively cutting drive. At the same time, more of what power remains is directed upwards as lift, so overturning force is diminished even further. The effectiveness of these measures is apparently so high that the Oceanic sailors never felt the need to develop any sort of reefing system. [Make sure you check out the image of a proa so rigged]
which begins to resolve my conundrum while allowing me to also reef as desired.I don't have to worry too much about lateral spill as the mast cradle prevents a lot of that and since i do usually sail with the spar close to the deck (as I assume/ understand that I can get more lift per sq metre closer to the surface of the water) I guess my options may be simple.
My challenge is, I guess, to locate the 'sweet spot' on the mast arm where I can get the best ergonomic pull. (Or so methinks). That's where some geometry may come into play.
I wanted to work through this before I started making the sail in case I had to incorporate design adaptions.