It will tack well?

I´m designing a smal sailboat, based on the lines of the well known sunfish, but, the good question is, It will tack well? Somebody here sells a boat from a manufacturer, called "sandshark", and a friend of mine says it is a boat that does not tack. How I can be sure this will not be a problem once my boat is finished?
THANK YOU

 

It is not really possible to answer without more data. Also, maybe your friend can't sail.

 

Thank you for replying, lets change the cuestion, are there boats that not tack well or not tack at all? can anybody take a look at my design and tell me what do you think? I can mail images, or put it somewhere here (I do not how to share my images).
Thank you.

 

The Sunfish is an extremely responsive boat, and it's a breeze to sail one in a tight circle, which is something I did continuously soon after learning to sail on one, so easily did she stay on her feet.
If your boat is based on a Sunfish, then what differences are there that would make you concerned about tacking ability?
My suggestion is you find a Sunfish and do some sailing.

 

When writing your post underneath the writing area you have "Additional options" and in there "manage attachments" click it..

 

And here's one cannot tack http://www.youtube.com/watch?v=8Ow8QbXhZJU&feature=grec

 

Things that make a boat tack well:

Well balanced center of effort and center of lateral resistance.
Proper helm balance with a bit of weather helm.
Lateral resistance concentrated in CB or DB.
Adequate rudder size and depth with rudder well aft.
Minimum fore and aft spread of sail area. Cat rig best.
There are others but these are the main ones.

Things that make a boat slow to tack.

CE and CB not well balanced.
Lee helm.
Lateral resistance spread out fore and aft in hull or long keel.
Rudder too small or too close to center of lateral resistance.
Sail area spread fore and aft as in Ketch or schooner.

 

I built an 18ft trimaran with no plans, no specs - juts to get out on the water.

Totally underpowered in the sail plan, and it was a long thin V main hull - not good for turning at all. Obviously it would not tack well.

I replaced the jib with one double the size, moved the mast step a foot forward - and voila, it tacked really easily.

Lesson 1 - sail sizes and mast steps are a flexible way to achieve the correct balance.

Lesson 2 - spending a few hundred bucks on a proper boat plan saves months of messing around and experimentation.

 

Commom sense gets you there. You get an idea after a while of what makes for a boat that rides as if on rails and one that could spin on a dime. I suppose you could experiment by playing with a tub of butter, seeing what shapes did what when pushed and turned on the surface.
No big secret. It's all very simple.
There are two aspects of tacking that matter. The first has to do with quickness of turning. The second has to do with velocity made good, or how efficiently a boat eats distance toward the wind's direction.
My own boat is lousy to weather, primarily because the keel is long and shoal. Yet she's one of the most pleasant boats to sail---- hardly any fooling with the helm. On any point of sail, she feels exactly like she's on rails. The tiller doesn't have to be swung back and forth. This makes for extremely enjoyable helming.
The interesting thing is, while she's slow in stays, she'll come around every time just by working the jib. Before I added the jib and relocated the mast, she was a cat rig, and I was often caught in irons.
Lots of factors contribute to a boat's ability to tack well, as that foregoing example shows. If you've got a long keel with attached rudder, and a cat rig to boot, that boat will sometimes have difficulty tacking. When the distance between the centerboard/keel and the rudder is increased (by making the appendages shorter and deeper), a single sail (cat rig) like a Sunfish is a snap to tack.

 

I only sailed a sunfish once, there was hardly any wind and I knew zip about sailing, but I had not trouble. Turns on a dime and will move in a breeze that can hardly be felt.

There's a lot of quite clever design in that simple looking boat. It would be easy to make a "look-alike" that did not perform well if you don't know boat design.

I couldn't find much on the sandshark, at least not a sailboat - it's a name that's been used for a lot of different craft.