Quoting Mike Crawford <email@example.com>:
> You make good points with respect to stays and headsails. However,
> one could also make the case that technological developments in the
> past fifteen years have made stays and headsails less important than
> they used to be.
> Arguments for a wishbone boom, unstayed, wingmasted una rig (in
> either a single or schooner setup):
> - It's common for boats competing for the speed record to lack a
> headsail, and instead use a variation of an unstayed, wingmasted,
> shaped main.
> - The speed record current is owned by a windsurfer using a wishbone
> una rig. Granted, Maynard uses a planing board the size of a large
> spoon, but he's still using an una rig.
> - A lower speeds, Wyliecat boats (catboats that use a single
> wishbone-boomed una rig) have beaten larger boats upwind, when many
> people would argue that a headsail will really help.
> - The una rig, especially if nicely tensioned, presents a very
> efficient swept back profile that works well without a headsail.
> - Stays generate a surprising amount of drag without contributing
> anything to forward motion. While a portion of a flexble unstayed rig
> will also generate drag when the rig flexes leeward, it will pop right
> back into generating lift once a gust passes.
> - The wishbone una rig is particularly adept at generating lift, and
> should require relatively light winch loads unless running. With the
> sail being self-vanging, the only load on the mainsheet is that which
> is required to pull the sail just past the point where it luffs.
> - With only a boom tensioner and a mainsheet, the wishbone una
> requires less time and effort to achieve optimal sail shape. Unless
> you have a full crew to pull strings all the time, the simpler design
> is likely to enhance speed over the course of a race.
> - The ability to fly the windward hull is actually much more
> critical to reducing overall drag than extra sail area or stays. But
> keeping that hull airborne, or just skimming the water, is a delicate
> balancing act. In this scenario, you're much more likely to be able
> to hold that balance with a rig that can absorb gusts than with a rig
> that doesn't give at all.
> - The lower center of effort on a schooner una rig, as compared to a
> taller easyrig, will likely allow it to generate more lift for the
> same heeling moment. Given that both boats use two sails, and a
> stayed easyrig will have some additional drag of its own, the lift to
> drag ratio of the schooner rig will probably be equivalent or better.
> With that said, I do love the easy rig -- it's hard to dislike a rig
> that's so darn easy to sail.
> It's just that any boat in my future plans needs to fit under 65'
> bridges, and a 64' easy rig on a boat the size of the visionarry isn't
> going to give me the light wind performace I'd like. Thus, I've
> adopted a schooner rig with wishbone-boomed mains as my new dream, and
> have in the process become quite a fan of the una rig.
> - Mike
I agree with pretty much everything Mike has said here.
As soon as someone will give me A$250K for XL2 I will start on a 50'
unstayed schooner rig with wishbones, fixed spade rudders, tiller steering and
This message was sent using MyMail
Yahoo! Groups Links