how are you going to make the larger sail?I usually sails in a small reservoir near by. The typical wind condition is very light
less than 10 mile/hour, around 5 mile/hour most of time. I am thinking of speed up
boat with more sail area, by streching spar length in order to fit a bigger sail.
The current length of spar is about 14 ft. By increasing mere 3 feet each spar, I can add about half (44%) of sail area from class sail. I know the modified boat is gonna to be tippy. But with stable sunfish hull, and my heavy body weight ~200lbs. It might not that too bad compare to laser, or even mention a skiff, such as 29er.
Has anybody tried that before? Any suggestion?
how are you going to make the larger sail?
are you gonna make it yourself?
Yes, I was thinking to add one wide strip attach the real end of original sail.
My concern is if I need compensate with possible slight shift of center of sail area (which wind force acts on) with other change, such as rudder and centerboard shape.
I heard the term of 'Weather helm' , is this will likely occur? How big of effect for such change?
if you are getting larger spars you´ll need a larger mast and larger blades too to compensate the amount of power you are getting from the sail
You are suggesting 44% increase in sail area ?????? By the time you make accomadations of design you may just as well try a bigger boat. I would venture that the radical change to sail area you are suggesting will not only create a bunch of other problems , It won't improve performance in the light winds you have mentioned. IMHO of course.
You can go to Island Packet Yachts and get a Big Fish sail and spars right over the counter.Maybe you can find just a bigfish sail for sail, and then put it on extended spars. That way at least you will have a quality sail.
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There needs to be balance
Center Of Effort by Dave Acree
http://www.myrc.org/Library/centeref.htm
Balance Your Helm for Speed
http://johnellsworth.com/writing/nautical/balance_helm/balance.html
The physics of sailing
http://www.animations.physics.unsw.edu.au/jw/sailing.html
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I'm not saying chew on all that physics. Just showing that if you want to make a design change that truly effects performance there are some concepts of balance you need to be aware exist.Wow! That is a lot to chew on.
This can also be accomplished by making the boom adjustable in the gooseneck by installing a quick release pinch bolt.I might have to increase the height of mast ( so I can shift the whole sail forward with higher hanging point for the up-spar).
Keep in mind the Sunfish was designed as an all around sports boat, easy to learn sailing on. Performance enhancement typically comes after first time owners master the basics.Personally, I believe the length of spar of current 14 ft, is bound by the length of boat for the shipping purpose. Other than loss of some of sail efficiency while increasing the sail area, there are no foreseeable factors against boat speed increasing.
If you hear of any full range of boat parts that come cheap, please let us know.The price of BigFish is about $5000. I think their parts will not cheap.