Turbo SNARK

So a few weeks ago I wound up being given a free Sea Snark that Harkens back to by childhood days learning to sail. Even then a styrofoam boat was a bit of a joke, but now...

Anyway the boat is being used on a small city bayou here in New Orleans, and while I accept it as a joke, I have started to fiddle as I do with all boats to get more performance.

1) I got rid of the stock rudder, and switched to a high aspect foil.
2) epoxied the bottom, and fiberglassed the sides as rub rails
3) new foil dagger board.
4) added a tabernackle cobbled together from an old antenna mount.

Now I am stuck facing what to do with the sail. At just 45sq foot it is a little small for a light wind joke boat, so I am thinking of reusing the stock parts, and creating a balanced Lug rig. But I have no idea what proportion of the sail should be forward of the mast. No idea what the conventional wisdom is for the angle of the yard, and no idea if I need to build camber into the sail or just make it flat.

Either way the sail will be polytarp, since the goal is to keep the whole boat worth less than $200.

 

Why not use just a mast and a more or less triangular sail-maybe w/o a boom.
Maybe you could just rotate the mast to reef and/or store the sail. Keeps the part count at the minimum. If you need battens make them vertical?

 

If you're going to go with a balanced or standing lug, the attachment point normally places about 1/6th of the yard in front of the mast. And balanced lugs are usually peaked less than standing lugs, but more than dipping lugs.

 

Make up a bigger lanteen, with longer spars and some poly tarp material. You might need to rake the mast forward a bit, but do go nuts, keep it simple and toss some serious area at it. Whats' the worst that could happen - you'll break the boat (I've done it). I would think a lug would place too much leverage up high to be useful as a canal rocket (while it lasts).

 

Par,

I looked a larger lanteen but it would require all new spars. At roughly 13' each they would wind up bigger than the boat. Meanin I couldn't store them under it. Which is why I was looking at the lug already.

My biggest concern with the lug is a lot of the sailing is upwind, making the lug less desirable since they don't do so well beating.


At this point I am a little concerned for my sanity but there is something awsome about sailing an oversized ice chest again.

 

Actually, luggers do very well upwind. Check out this site:

 

A good place to go to find out about balanced lugs is pdracer.com. The balanced lug is one of the two most popular rigs used in that class.

Here's a few rules I've learned from those who have designed a lot of these.

1.) luff should be no more than 1/5 the foot length in front of the mast,
2.) Halyard should attach about 40% aft the front end of the yard, and
3.) maximum camber should be further forward than on most fore and aft sails, about 30% aft.

That's about it.

The pitch of the yard doesn't seem all that important.

If you are using the original mast, you are somewhat limited to how much pitch you can give the yard. More pitch = less sail area. I would go with about a 30 deg. pitch (from horizontal), so the leach would end up being significantly longer than the luff.

The original rigs on these boats had flat cut sails.

You could keep the original latin rig, but make a cambered sail for it. That alone may make it up to 50% more powerful.

 

Sharpi,

Are you sure about the luff being 1/5 the foot leingth in front of the mast? The boat is cat rigged, so this would leave me with a very short luff (12" or so).

My plan for now is to at least try out a balanced lug, with a 10' boom, 10' yard, and a six foot luff. This is the largest I can go with the existing spars, so all I need to do is buy a tarp and get to cutting. I am thinking a 30 degree angle from horizontal for the yard.

Since its just a joke sail I plan to just cut it flat, see how it goes, and make modifications from there.


One thing that has really amazed me is how much faster the boat is with a epoxy sheathed bottom. Getting rid of the rough bottom made a very noticeable difference in speed. The foils don't seem to be worth the effort that went into them however.

 

Your luff should be about 2.0 ft in front of your mast.

According to my spreed sheet, you will end up with around 79 sf of sail.

I would suggest going with a 5.0 ft luff, so the yard is not hauled all the way to the top of the mast. A 5.0 ft luff will give you just under 70 sf of sail, with a 1:2 (rise/run) yard pitch (about 30 deg.).

Your biggest handicap seems to be the length of your mast.
Just how long is it?
My guess is about 8.0 ft.

The Horizontal CA will be quite close to that of the original rig, which is something else to consider. You don't want to have to sail with your rudder blade torqued way over to leeward and have it's resulting drag using up much of your new driving power.