Jim Michalak's Boat Designs

118 E Randall, Lebanon, IL 62254


A page of boat designs and essays.

(15Mar10)This issue rerun the lugsail rigging essay. The 1 April issue will look at ideas to strengthen masts.

THE BOOK IS OUT!

BOATBUILDING FOR BEGINNERS (AND BEYOND)

is out now, written by me and edited by Garth Battista of Breakaway Books. You might find it at your bookstore. If not check it out at the....

ON LINE CATALOG OF MY PLANS...

...which can now be found at Duckworks Magazine. You order with a shopping cart set up and pay with credit cards or by Paypal. Then Duckworks sends me an email about the order and then I send the plans right from me to you.

MUST SEE WEBSITE!!!!

...Our old buddy Garth Battista of Breakaway Books has escaped! He towed his Cormorant and his family, between East Coast blizzards, from New York to Miami and is now acruisin' with them all in the Bahamas, etc.. He keeps an updated log at

http://blog.mailasail.com/seafever

He is on a never ending search for ice cream and internet access. When he finds both at the same time he posts photos like:

Garth is like most of us, an inland waters guy who went out and built a boat for himself. Seems like just yesterday he sent photos of his first Toto. THREE CHEERS AND GOOD LUCK!

Left:

AND THREE CHEERS FOR THE EVERGLADES CHALLANGE CREWS. Here Gary Blankenship leaves from Tampa on his fourth EC race, only this time solo. And four days later he finished in Key Largo. Next day Michael Monies and Andrew Linn finished in their "paint still wet" Laguna. More on that below.

 


Contents:

 

Contact info:

jim@jimsboats.com

Jim Michalak
118 E Randall,
Lebanon, IL 62254

Send $1 for info on 20 boats.

 

 

Contents


Rigging A Lugsail

BASIC BALANCE....

This applies to any sort of sail rig. For proper sailing the sail rig forces need to balance around the hull forces.

Look closely at Figure1 and see that the center of the sail area is placed right above the center of the leeboard's area. For boats like mine with shallow underbodies and deep narrow boards this is the way it has to be. You can't tinker very much with this if at all.

Here is what happens. In general you can think of the force of the wind as a giant finger pushing at the sail's center. Opposing that force is a giant finger pointing the other way at the center of the leeboard. The hull tends to rotate about that deep narrow board. So if those two forces are in vertical line the boat will not try to rotate and will in general maintain its heading.

If the center of sail area is moved aft of the leeboard, the boat will rotate into the wind if left on its own. To keep the boat on course the skipper needs to tug on the tiller as shown in the top of Figure 2. This is called "weather helm". Weather helm reduces the load on the leeboard and should result in a faster boat. If the skipper falls overboard the boat should rotate into the wind and stall and with luck wait for the skipper. A light weather helm is considered to be ideal.

Now take the case of the builder who modifies the rig so that the sail area centers forward of the leeboard. This might be by changing to a rig style with a jib, or perhaps by relocating the mast forward. Now the two opposing giant fingers on sail and leeboard are not in a vertical line and the boat will want to rotate around the leeboard bow going downwind. To hold the bow on course the skipper must correct by pushing the tiller as in the bottom of Figure 2. This is called "lee helm". Lee helm will increase the reaction load on the leeboard. If the skipper falls overboard the boat will turn downwind and take off without him. Lee helm is usually not considered to be good.

So the way I like to approach it is to keep the center of the sail area directly above the aft half of the leeboard. You might find lots of variations on the rules that hope to provide proper helm feel. Try them if you wish. But keep in mind that if you build the boat and it has lee helm, you need to move the sail area aft. If you have excessive weather helm, the sail area needs to be moved forward.

NOW, BACK TO THE RIGGING DETAILS.....

TYING ON THE SAIL...

I greatly prefer individual ties through the grommets although lacing looks neat. But the individual ties allow for last ditch sail shaping. If you think you needed more round in the head of the sail for example, you could make the ties in the center of the yard tighter than those on the ends. Also, a failure of a tie or two is of little consequence where a failure of a lacing line will be total.

One important note. The ties in the corners take most of the load. They should be tied as shown in the figure in two directions.

HALYARD/YARD ATTACHMENT...

Let's look at the sail and halyard attachment in Figure 1:

As you see, the balanced lug sail pivots around the mast. I guess all sails do. But the balanced lug has the mast running through its middle somewhere, as do other Lugsails, junk sails and lateens. While the mast may interfere somewhat with the aerodynamics of the sail, great benefit is gained in proper "balance" of the sail areas that are in front of the mast. In particular if things are properly placed, the sail will twist less than similar sails that use the mast as a leading edge. As a result the lug is a low tech sail that can be more efficient to windward than you might expect.

One trick to rigging these efficiently is to get the "balance" correct. By my experience the yard should be hoisted about 40% aft on the yard. If you hoist farther forward than that you will get harmful sail twist when sailing to windward. Hoisting too far aft can make the sail uncontrollable. I have often seen in the older literature the advice to hoist at 33% aft. That will work OK but it has been my experience that all the stretches and sags in the system conspire to pull the sail aft with respect to the mast. So if you tie the halyard to the yard at 40%, in use the sail swings aft very close to that 33% value.

(You see the designer has little choice of mast placement once the sail has been chosen. The leeboard can only go at the hulls widest beam. The sail area must center right above it. The mast must cross the yard at a certain point. )

We need to rig the halyard so the sail stays near that 40% position by binding it somehow to the mast. This is especially important while reefed or while in rough water that will force the yard to pump back and forth on the mast. I know of three suggestions.

First for small simple boats that won't be reefed the best solution is to run the halyard through a simple hole in the top of the mast, tie it to the 40% position on the yard, and hoist solidly to the top of the mast. There must be a small amount of slack at the masthead of course to allow the yard to swing but that will appear automatically when you tension the sail with the tack line.

Second you can try the tightening noose system shown in Figure 3. Here the halyard runs in a loose loop around the mast before going to the masthead. It will stay loose until the yard is hauled up all the way. Then additional tension in the halyard constricts the noose (until it hits the stopper knot) and secures the yard to the mast. You will need rollers on the noose to keep the halyard from binding on the mast. I have a feeling that this is the most reliable system.

Third method works well with round and slippery masts. A loose slippery ring is simply dropped over the halyard and mast. I use this system on my Piccup Pram using a section of large PVC pipe as a ring.

THE TACK LINE....

Figure 5 shows the tack arrangement I prefer. As with the yard, the boom must be secured to the mast to prevent pumping in rough water. The actual location of the tack on the yard is not too important. In fact if it were at the very front of the boom you would have a standing lug. The standing lug is probably easier to rig and reef than the balanced lug but in my experience lacks the great manners of the balanced lug in sailing downwind.

The boom has a small cleat on it with a lanyard that wraps around the mast to locate the boom fore and aft. That loop should be fairly loose to allow easy up and down motion of the boom. This loop needs to be set up before the yard is hoisted to prevent the sail from blowing around and making a spectacular and dangerous kite during hoisting.

The actual tack line I prefer is a simple line that runs from the mast step over the boom and down to a cleat at the step. So with the boom loop attached, the yard is hoisted, then the tack line is passed over the boom, pulled very very tight, and cleated. In effect you have now a two to one tackle. All sail tensioning is done with the short and handy tack line and not with the halyard. On my Piccup I run the tack line through a cam cleat to allow for quick adjustment although I don't consider that to be as secure as the good old jamb cleat. In my opinion the tack should always secure to the hull and not to the mast. Securing the tack to the hull will secure the entire mast and rig to the hull in event of a capsize.

Here is some advice about how much to tension the tack line. It varies with wind strength. Look at the sail as you do it. See Figure 6. As you tension the sail with the force of the wind in the sail, stress folds called girts will appear in the sail. If the girt runs from throat to clew you need more tension. If the girt runs from head to tack you either have it right or can reduce the tension. A perfect setting will have no girts. Usually at the initial setup I put in a good girt from peak to tack. Then I watch it while sailing to see if that girt disappears. Then when convenient I trim as required. Remember that changing sailing conditions will change the tension requirements.

THE SHEET...

Nothing fancy needed here. Almost anything will work. Because the sail is balance already to a great degree the sheet forces are less than with other sail types. Because the tack is pulling down in the middle of the boom, the boom has less tendency to lift so downward pull of the sheet on the boom is of less importance. The location and lead directions of the sheet are of little importance also. It's another advantage of the balanced boom. By the was, if the boom is omitted to make the sail boomless, the sheet location is very critical and its needs change all the time. I think the boom is a great invention! The boom on a balanced lug can be quite light and still work.

SAILING ADVICE...

Watch the leading edge of the sail for luffing, as with about any sail. You should be able to tack through about 100 degrees effectively, although if you are really interested in getting somewhere you might sail it more freely, say up to 120 degrees between tacks, especially if the wind is unsteady. While reaching or running a balanced lug sail, even a cheap polytarp one, will keep up with any conventional sail.

Also it should be mentioned that one of the most effective ways to trim the boat, helm-wise, is to rake the mast as required to move the sail are fore or aft. You can see that a small amount of rake will move the mast head quite a bit and the entire sail will go with the masthead. Old time boats had adjustable mast steps or partners. On my designs you can usually shim the mast partner on the bulkhead. It's one place where tinkering pays off. Making a mast a bit longer than shown on the plans is also almost always a good idea as it allows for this tinkering not to mention real life stretch of the rigging.

Contents


Laguna

Laguna, Sailboat, 23' X 5.5', 450 POUNDS EMPTY

This boat was designed for Duckworks to run the Texas200, 200 miles of brisk downwind running they say in the somewhat protected waters of the Texas intercoastal waterway. The boat was supposed to be cheap and quick and hold two crew with floorspace for them to sleep on board. The basic idea I had was to stretch the Mayfly16 with an 8' plug in the middle. In the end I kept the basic cross section and stretched it out with a simple flat iron skiff shape. The bottom is the width of a sheet of plywood which simplifies things even more. The first doodle looked like this:

I drew it up in detail getting this:

And a card model from the detailed drawings looked like this:

My cross seats are supposed to be big and comfortable and removable to give sleeping room on the floor. Each crewman has his own stateroom.

The sail rig was to be a split rig with identical lugsails fore and aft with the option to sail with just one of the sails mounted in the center, like this:

I think the single sail option would be preferred if sailing solo since that fore mast is way up yonder and one may not be able to handle it and the tiller at one time.

The prototype was quickly built by Gordo Barcom in Texas and here he is blasting along with family and polytarp sails straining. It was clearly a fast roomy boat:

Then another, the Blue Laguna, was built and run in the 2010 Everglades Challange, 300 miles from Tampa to Key Largo, by Andrew Linn and Michael Monies. This boat had very little testing time as far as I know before the race. But they finished in 5 days and a bit but I think they slept in motels for two of the nights while the "press on regardless" guys were daring the night waters. Here they are launching off the beach (a requirement for this race):

And then pushing off in shallow water (there is a Sea Pearl behind them for comparison):

Finally a really nice photo of them approaching one of the three checkpoints in the race:

I think both Gordo's boat and the Blue Laguna have been modified in details from the blueprint but the rigs and basic hull features all look correct. I've noticed that no one takes sleeping floor space as seriously as I do but that is OK.

Well, I was thrilled. My main caution would be that this probably is not a good solo boat due to its size and split rig. I think it might be a good family boat in that there is plenty of room for everyone and a rope for all idle hands to play with. The other caution might be that, even though the boat has big buoyance boxes, it also has large cockpits to swamp in a knockdown and it will roll upright with a lot of water to bail. So you note on Gordo's boat he has inflated fender tied to the mast head, an idea to reduce the carnage of a knockdown.

Plans for Laguna are $45. It is all simple nail and glue construction needing six sheets of 1/4" plywood and five sheets of 1/2" plywood.

Contents


Prototype News

Some of you may know that in addition to the one buck catalog which now contains 20 "done" boats, I offer another catalog of 20 unbuilt prototypes. The buck catalog has on its last page a list and brief description of the boats currently in the Catalog of Prototypes. That catalog also contains some articles that I wrote for Messing About In Boats and Boatbuilder magazines. The Catalog of Prototypes costs $3. The both together amount to 50 pages for $4, an offer you may have seen in Woodenboat ads. Payment must be in US funds. The banks here won't accept anything else. (I've got a little stash of foreign currency that I can admire but not spend.) I'm way too small for credit cards.

I think David Hahn's Out West Picara is the winner of the Picara race. Shown here on its first sail except there was no wind. Hopefully more later. (Not sure if a polytarp sail is suitable for a boat this heavy.

Here is a Musicbox2 I heard about through the grapevine.

This is Ted Arkey's Jukebox2 down in Sydney. Shown with the "ketchooner" rig, featuring his own polytarp sails, that is shown on the plans. Should have a sailing report soon.

And the Vole in New York is Garth Battista's of www.breakawaybooks.com, printer of my book and Max's book and many other fine sports books. Boat is done, shown here off Cape Cod with mothership Cormorant in background, Garth's girls are one year older. Beautiful job! I think Garth is using a small lug rig for sail, not the sharpie sprit sail shown on the plans, so I will continue to carry the design as a prototype boat.

And a new Down Under Blobster is off cruising under outboard power as it waits for its sailrig.

A view of the Caroline prototype showing a lot of the inside, crew on fore deck. Beautiful color:

And here is another making I think its maider voyage in the Texas 200. (I'm told the Chinese rig will be replaced by the blueprint rig.)

I gotta tell you that on the Caroline bilge panels I made an error in layout and they are about 1" too narrow in places on the prototype plans. I have them corrected but it always pays, even with a proven design, to cut those oversized and check for fit before final cutting.

And a Deansbox seen in Texas:

A Twister goes together in good shape. He moved the cabin bulkhead aft for more cabin, less cockpit:

Contents


AN INDEX OF PAST ISSUES

THE WAY BACK ISSUE ARCHIVES

1apr09, Laguna, Frolic2

15apr09, Rigging Sharpie Sprits, Sportdory

1may09, Small Boat Rudders, Robbsboat

15may09, Rowing Gear, Roar2

1jun09, A Bimini Boot, Ozarkian

15jun09, Phil Bolger, Vector

1jul09, Rend Lake 2009, Fatcat2

15jul09, Rowboat Setup, Mikesboat

1aug09, Sail Area Math, Family Skiff

15aug09, Beach Designs, Cormorant

1sep09, Taped Seams, Trilars

15sep09, Birdwatcher Cabins, Philsboat

1oct09, Bevels, Larsboat

15oct09, Transom Height, Jonsboat

1nov09, Ballast Again, Piccup Pram

15nov09, Ballast Again2, Caprice

1dec09, Weight Problems, AF4Casa

15dec09, Ballast Again3, Raider

1jan10, Knockdown Recovery 1, RioGrande

15jan10, Knockdown Recovery 2, Caroline

1feb10, Emergency Flotation, Mayfly16

15feb10,IMB Capsize Test, IMB

1mar10,Wood Vs Aluminum, Blobster

SOME LINKS

Mother of All Boat Links

Cheap Pages

Duckworks Magazine

The Boatbuilding Community

Kilburn's Power Skiff

Bruce Builds Roar

Dave Carnell

Rich builds AF2

JB Builds AF4

JB Builds Sportdory

Hullform Download

Plyboats Demo Download

Brokeboats

Brian builds Roar2

Herb builds AF3

Herb builds RB42

Barry Builds Toto



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