Gaff rig with jib?

No on the first question. but I hope I have given you enough info so you can sketch it yourself.

Yes on the 2nd.

I'm going to post it mainly so you can get an idea of how the balanced jib works and the advantages of having one.

See attachments below.

Here's the text:





'PENCIL' RIG



This proposed rig is a for a hybrid boat. In this case a boat that is part rowboat and part sailboat. Where the sailing is done mainly in stronger winds and rowing is done for lesser wind strengths. To be really successful it should be able to be rowed and sailed at the same time.

For the purpose of recreational fishing, it would be nice to have a rig that doesn't foul your fishing pole every time you change tacks. It would also be nice to adjust your sail area easily to control your speed over the bottom.

This is what this rig is all about.

It has a total of three sails. Each is either fully set or completely struck.

The first is the MAIN SAIL (1.). It is set below the BOOM (4.) and is lashed directly to to the BOOM and the MAST (8.).

Above it and lashed only to the BOOM is the TOP SAIL (2.). A JACK LINE (not shown) keeps it's luff from fluttering too far on either side of the mast.

In front of the MAST is the BALANCED JIB (3.). It's foot is lashed to the JIB BOOM (6.), which is attached to the boat with a TETHER (7.). It's top corner is held up with a halyard (not shown).

Setting Sail

First, the MAIN HALYARD (5.) raises the aft end of the boom. This sets the MAIN SAIL.

Then, the BRAILE/DOWNHAUL (10.) is slacked and the TOP SAIL halyard pulled, raising the TOP SAIL.

Finally. The jib halyard is pulled, raising the BALANCED JIB.

Striking Sail

The sails will usually be struck in reverse order, with the BALANCED JIB coming down first and the MAIN SAIL coming down last.

Sometimes, when the skipper wishes to troll down wind, for example, the jib will be the only sail set.

In really windy conditions, the MAIN SAIL will be left up to help the skipper make port against a headwind, as he rows as well.

Once the main halyard is slacked, the MAINSAIL should collapse quite reliably. It should set quite reliably as well, as there are no sliding parts invloved.

Drawbacks

The biggest drawback with with this rig, is that the Horizontal Center of Area (HCA) shifts considerably when the BALANCED JIB is set or struck. This can be dealt with in a number of ways:

1.) A long centerboard, or long side centerboard (sometimes called a lee board) can be swept further aft, once the BALANCED JIB is struck.

2.) A fore and aft sliding dagger board, or side dagger board can be slid forward, when the BALANCED JIB is up and be slid aft when it is down, or

3.) A smaller centerboard in the bow can be lowered when the BALANCED JIB is set and raised when it is struck.

Another drawback is that the mast must be quite heavy and stiff for the amount of sail it actually sets. This is because it must stand the tension of the BALANCED JIB's halyard and must be free standing. This, in itself, will seriously limit the amount of sail area that can be carried, making this rig best as an auxiliary sail, not a main propulsion rig.

Lastly, there is the inefficiency of having the MAIN SAIL divided up into two smaller, triangular sails, with the BOOM in the middle, instead of at the foot, where it would serve as an end plate.

Advantages

There are no expensive moving parts. Just about all the hardware is simple and straight forward

The jib comes down into the cockpit, instead of sliding down a fore stay, far from the skipper.

Shortening sail is easier than on just about any other simple rig, except a Chinese lug.

 

Gaff rig w/balanced jib described in previous post

CB King.

Attached is a crude drawing of the rig I described in an earlier post. All the dimensions are to the proportions of that rig, so you can get a general idea of what it would look like.

It turned out the mast could be about six inches taller, but it is drawn as originally described. The bowsprit should be maybe three inches longer, to keep the aft end of the club boom from smacking the mast.

The base line shown is at the bottom of a would be boat. The tether would be shorter than shown, as it would attach to the end of a bowsprit at deck level.

Here is a description of how the rig would work. The numbers in what follows correspond with the drawing.

Here goes:

GAFF RIG W/BALANCED JIB

Starting off

The front end of the boom (2) usually is attached to the mast with what is called a 'goose neck'. The front end of the gaff (5) usually rides up the mast, as the sail is raised. It usually has either a 'saddle' or 'jaws' to hold its front end to the mast, but allow it to slide up and down the mast. The sheet lines, which control the sail's angle to the wind should already be run through their pulleys. You will have two, one for the main sail and one for the jib. The tether (6) should be attached to the club boom (8) and to the end of the bowsprit.

Raising Sail

First the throat halyard (1) is pulled. This raises the front end of the gaff (5), the lower part of the sail, and the Boom (2). Next, the vang (3) is attached to keep the aft end of the boom from rising. Next, the peak halyard (4) is pulled. This raises the aft end of the gaff, raising the upper part of the sail. Then the sheet line (not shown) is adjusted to get the boat underway.

The jib halyard (7) is pulled, which raises the jib, lifting the club boom (8) off the deck. Its sheet (not shown) is then adjusted.

Lowering Sail

The jib almost always comes down first, by relieving the jib halyard (7). Then the peek halyard (4) is relieved, dropping the aft end of the gaff (5). Last, the throat halyard (1) is relieved, which lowers the mainsail completely.

 

I'm posting my pictures in a gallery:

http://www.boatdesign.net/forums/profile/cardboardking.html

As you can see, I'm not as close to being ready to rig it as I thought I'd be by now. But I'll get there soon.

All of my real cardboard constructions are already a hybrid of cardboard, wood and plastic. Mostly it has involved laminating wood pieces onto the cardboard in the areas where the stress is greatest, but I still want the sheet to be thin. And then, whenever I drill a hole for a screw or nail, I Gorilla Glue a piece of plastic drinking straw into the hole. I figure my rudder plate will manifest itself in some way similar to this.

I don't intend to have a daggerboard. I've decided to go with a single, centered keel. My intended result is going to be something like the following.

This way, the forward portion of the bottom and the keel will form a kind of tripod for the boat to rest on as it nears the shore. I realize it may not be the ideal configuration for racing, but I think it's rather elegant. And cool-looking.

 

you will need more lateral resistance forward... You will have too much lead with just a skeg like that

 

the keel idea will work but it should run further forward, and realize it will compromise your ability to point into the wind.

You might consider trying strakes at the chines instead, it makes the hull act like a "lifting body" to give more lateral resistance.

 

You will almost certainly do better with a side mounted dagger board, side mounted center board, or a leeboard.

The real problem with a long keel is what happens when you have to beach the boat.

With a cardboard hull, you don't want any concentrated loads, especially on the bottom.

The skeg arrangement you drew has the Center of Lateral Area (CLA) too far aft. You can make it work by moving the rig aft as well. But only to a point.
Move it back too far and the mast ends up in your lap and the turning arm (the distance between the CLA and the rudder) gets too short, making the boat hard to control.

To fix that, you need the keel to actually be beneath the boat.

Then, when you try to drag the boat up onto the beach, the keel either wants to flop over or push its way through the bottom of the boat.

With a side mounted centerboard (mounted outside the hull, with no trunk) or a leeboard, the two I would recommend, The only loads are twisting loads on the side of the boat. The top of the side will want to twist inward when the board is upwind, and outward, when the board is down wind.

Sturdy side decks, made mostly out of cardboard, can be made to resist such loads.

If the board strikes an object underwater, it just swings back.

It can even have a bunji cord to pull it back down.

 

Okay, how about something like this?

Unlike the wooden versions, my PD Racer actually has a totally flat bottom in that center section. The forward and aft sections of this skeg (or keel - still not quite sure what the difference is) would make a flush, straight line with the bottom. If necessary, I could make two of these, each slightly offset from the center.

And, just thinking in text, here, what would happen if I only had the front ones, and left the back ones off?

 

It won't handle very well... You will have a hard time getting the bow around when tacking. The leeboard in the original design is there for a reason. It provides lateral resistance to the sideways push of the sail while at the same time it balances the forces of the water on the hull. The boat tends to pivot around the board while tacking and turning. What you have is the exact opposite. You have a skeg in front and back and nothing to pivot around in the middle.

 

You will probably have too little Lateral Area.

There have been pdracers with long keels, but they usually extend much further below the hull (6 to 8 inches or more). Some have had two long keels and even those extend below the bottom of the hull.

For the record, the arrangement you have here is what is called a 'skeg and cut water' (the skeg is aft and the cut water is forward) This is what was used on sailing ships that were narrow enough and deep enough for the hull itself to act as a keel.

As Lewisboats has said, such an arrangement hampers maneuverability.

But that can be worked around.

The forward sail, or the main, if there is none, is backed to force the bow to swing through the wind to the other tack.

Here is an example of a side mounted centerboard: (see attachment)

It is held on by a single bolt, which passes through the heart shaped reinforcement, the board and a reinforcement inside the hull.

This particular design has two such boards, one on each side, which are both kept down while sailing.