A feature added to our model sailboat kits, (nov.01) gives you even more design options, "the cabin." You can step a mast just about anywhere on a hull, even rig a Mk I hull with two masts! If you already have a model, (but no cabin) we will show you how to craft your own, first let's explain how it works.

The cabin is attached to the sailboat deck by running a screw up through any one of the mast steps in the hull.
The screw feeds into a pilot hole underneath the cabin at one end. At the other end of the cabin is a mast step.
The pilot hole is drilled at the farthest point on one end that will take a screw without the danger of splitting the wood.
You can drill your own pilot hole any where between this hole and the mast step to precisely locate the step where you want. The cabin may be positioned with the mast step end positioned forward or aft.

The screw that holds the cabin in place should be tightened only enough to keep the cabin in place. You should be able to twist the cabin to the side to adjust the centerboard. Never over tighten the screw, you could possibly strip the wood fibres or even crack the cabin itself. The solid brass slot screw provided can be hand tightened using the edge of a dime.

The cabin suplied is designed for function, not necessarily looks, weight is a major factor, for there should not be any unnecessary weight or surface area topsides. So it was made using a minimum amount of wood.

There is a slight drawback to using the cabin when it sits over the well, the centerboard is not as easily adjusted since raising the centerboard usually raises one edge of the board above the deck surface. The cabin in this case must be twisted aside to make any adjustments and more care put into the board design. The centre board in any case, can still be adjusted fore and aft.

Another point to consider when using a cabin, is that the mast will be stepped higher off of the deck, so the gooseneck should be a bit shorter than normal. This also raises the sails centre of effort higher aloft compared to the same sail setting lower to the deck.

Crafting your own cabin.

The fist thing you will need is a piece of one inch thick wood. Cedar of course is the best choice. The best tool to have is a drill press with a brad tipped 1/4" drill bit. A hand drill will also work even though it may take a few attempts to get your hole plumb.

A 1" x 1" is actually about 3/4" and that is the minimal thickness that you need to secure a mast into. A 1" x 2" may be used, but the more weight that you place topsides, the more likely your sailboat will capsize. More weight will also slow the boat due to slightly more displacement. Don't forget you are adding the weight of the screw too.

Why not plan on making a few. You may even experiment with drilling the mast step at a slight angle to rake the mast.

A piece 3-1/2" long is all you need for a MkII, this is long enough that once attached with the screw, the mast step can be positioned over the centre of the well. A piece 2-3/4" for a MkI will do. Mark the wood with a pencil point to centre the hole.

After you have drilled the 1/4in. hole, use a 1/16th. inch drill bit for the pilot, be careful not to drill all the way through. I have rounded the top edges and slightly sloped each end on our kit versions. This is done after the holes are drilled. You can make yours as fancy as you like.

The cabin should be given a protective coating, this can be whatever you choose, paint, stain or natural oils. Also, do the bottom and down inside the step. (a cotton swab works well)

With the thickness of the hull, the size screw you can use is 1-3/4 or 2in. depending on how thick you make the cabin. It should be solid brass (#8). An alternative are screws made for exterior deck work. These are sold in most major outlets (Home Depot) in bulk, priced by the pound. (Note the tellers raised eyebrows when you buy... one!)

Fairing in center boards

Our sailboat kits come with two center boards, each is fitted to sit snugly into the boats' well. (As of Apr.04) One of the boards now come faired in, and can be used as it is, it is treated with an acrylic water proofing sealer, just as the sailboat hull. However, it should be painted, or varnished for best results.
The spare, or "stock" center board is oversized for custom designing the shape you want. You can reduce the area of the stock board up to half its size and still have one that will work, but the model will sail with a lot of leeway.

"Fairing" means to work the wood into its final shape. The most important aspect of fairing in your board is to obtain a foil shape. The foil manipulates the flow of water around the keel as the sailboat moves forward. Keep in mind that unless you are sailing directly down wind in still water, "moving forward" includes moving slightly sideways. (leeway)

For sailing downwind, the shape of the foil is not that important, for sailing directly downwind you don't need a board at all. You can adjust the board all the way back, pop it loose and let it float in the well, or remove it altogether.

For sailing windward a well shaped board means the difference between good and poor performance. Usually the board is slightly turned back to reduce drag, also at this point of sail the boat heels the most, and this causes a weather helm reducing the need for forward lateral resistance.

The ideal cross sectional shape of your centerboard will have its greatest thickness somewhere around the middle up to about one third the distance from the leading edge. From that point, the board gradually tapers to its trailing edge. The trailing edge, although very narrow should not be sharp like a knife edge, but have a flat squared edge. Water will have a tendency to cling to a sharp trailing edge, this slows the boat down. The flat trailing edge causes mini turbulents that spoil the clinging effect.

This is easy to do once you are finished shaping your board. Take a metal tool, like a screwdriver, and rub it along the edge at a 90 angle, flattening down the wood fibres. You don't have to overdo it, just enough that you can see it. Consider a full sized sailboats trailing edge is squared off at about 1/8".

The forward edge of the board should not be sharp, but a long oval shape. This creates less turbulent flow. The oval edge works like a car bumper pushing against the oncoming flow of water (yes, this does create drag) but water will flow around itself (water pressure area) better than a solid object with a sharp edge. The sharp edge will cause turbulents due to the sideways slipping leeway.

The gradual thickening of the board in the forward section deflects water in a way that produces lift, this lift helps reduce leeway and guide the board windward. This is just like the bow of the hull.
 As with just about every thing else in sail and hull design, every design advantage may also have its disadvantages, in short, the more lift a board generates (good) the more drag (bad). Consider the following examples of boards that have the same area.

*A long board will generate more lift than a short board but a long board will increase the boats heeling and have more knockdowns. This is compounded when the boat is heeling when the foil generates lift from down below and actually lifts the board up, turning the boat over. Also, It may strike bottom in shallow water.

*A wide board will give your boat great lateral resistance, making little leeway, but difficult to turn.(note the HUGE keels on pond boats)

*A thick board will (potentially) produce more lift, it will also produce more drag. You may be able to sail windward better, but it will be a slow go.

*More lift is gained when the board has its thickness about a third of the way aft of the leading edge, more speed comes with its thickness at the middle.

There are some examples in the illustration, using the spare "stock" board, the first two show some extremes, I wouldn't go beyond these sizes.

One, full length, and narrow. Good lift, low drag but plenty of leeway.
The next, wide and short, about two thirds of its original length. Good for shallows, rough water, good lift, but slow, lots of leeway.

The next foil was designed so that it can be raised up into its trunk, this one is good for those shallow tidal pools. Keep in mind the depth of the rudder too.

Sharp, square edges at the bottom of the board should be avoided for when they are turned back, will produce a point that causes turbulents. For this reason, an elliptical bottom is often used.

Just like when you craft a sail, making a pattern to work from is a good idea, a small piece of cardboard works well, and will help you to visualize the shape that you want- deep, wide, forward adjustable, retractable etc.

Some basic wood working tools that will be handy to have are a coping saw, a vise, hobby knife, various grades of sandpaper, and the most important tool of all, a dust mask.

Your spare board already has a rounded edge, there is not too much work you have to do to improve the leading edge, most of the work will be on the trailing edge.

Of all the different shapes you can try, one thing is important, and that is leaving most of the top area of the board its original thickness. Otherwise, you will defeat the wedge properties of the board. All of your fairing for the purpose of creating a foil is done on the area that gets exposed to the water.
 You may trim off some of the foreward top section at an angle to nudge the board slightly forward when it is partially raised. This moves the centre of lateral resistance with it.

You may also want to round off the top aft corner of the board so that when the board is slightly raised the boom will be able to swing across the deck when changing tack. Or, at least be able to bump over it without getting caught up.

The board is placed in a wood vise bottom up. About 1" of the thick part inside the vise. (You can improvise if you don't happen to have a vise laying around. Perhaps vise grip pliers, or a large c-clamp) Anyway, you want to be able to look straight down onto the bottom of the centerboard. You then take a full length strip of sandpaper about two inches wide, and fold it down the centre, abrasive sides out.
Holding onto each end of the sandpaper strip under tension, slide the paper along the side of the board. This is like a "shoe shining" motion, moving both arms back and forth.

Note: Water causes wood to swell, if you find that your board is sticking in the well to the point that you can't adjust it, rub a bit of candle wax around the top. You can also rub some around the heel of the mast while your at it.
If you make your own board that seems too lose, (when it is dry) don't worry, it will swell once it gets wet.

At some point, we will be taking a more detailed look at the science of foils, so click on over to fairlead and look for our updates.
Click for more on foil shapes and sailing your model windward.

How to Craft Bowsprits and Boomkins

Making a custom, or replacement, bowsprit is not all that difficult, you only need to have a few basic tools. A drill with a 1/16" bit. A well sharpened chisel, and sandpaper. A wood vice will help.

You can use any type of hardwood you happen to have, but most likely you will make one out of 1/4in. dowel left over from a broken or shortened mast.
First we want to trim off the base of the sprit where it sets on the deck at an angle. How much angle is up to you, you can even have no angle at all if you really want, keep in mind that the sprit will dive into oncoming waves if you don't give it some rise.

The angle is made by holding the dowel up with the end of the dowel down onto a work surface. The chisel is then used to pare down the end of the dowel, use the flat side of the chisel, it will naturally dig into the wood at an angle. You want the sprits base to sit perfectly flat on the deck, otherwise it won't stay in place.

Get the base flat by placing some sandpaper on a hard flat surface and drag the sprits base along it. An alternative is to use a fine toothed metal file (laid down flat). Set the sprit on something flat (like a metal ruler) and hold it up to a light to check your work.

You will need to grove the base at the top to make the sprit thin enough that the eye screw can set deep enough into the deck to hold it in place. You can start with the chisel to make a notch and then wrap some sandpaper around a piece of dowel(or whatever) and put some shape to it.

Mark carefully the place where you are drilling through, I use a sharp pencil point that will mark and dent the wood where the hole will be. This keeps the drill bit from travelling around on the wood surface and putting the hole in a wrong place.
Using a hand crank or electric drill, place the sprit in a wood vice to hold it secure. Keep in mind the angle of the drilling. Especially in the next step.

Now you will want to drill through the front end of the sprit. Mark the wood firmly where you are going to drill to form a pilot hole. And reposition the sprit in the vice. You may want to use a slightly larger bit (1/8") if you have one. This will make running rigging line through easier. Again keep in mind the angle you are drilling with.

You can dent the wood in a way that the eye screw will set into the bowsprit on the final turn of the screw. This will help the bowsprit to stay in position, yet still be able to turn aside if bumped. (Better to turn than break!)
Take the edge of a slot screwdriver and nudge the tip forward starting at the hole.

If you are using a drill press, set the sprit down on the work surface just like it would be if setting on the deck, resting against a secured block of wood so that the sprit will not spin around the drill bit once it pops through.
For the front end, lay the sprit down on its side, and hold its base firmly against the block of wood described above, this will hold it steady and give you a hole that runs horizontally when finished.
For a long bowsprit. First off, think about your sail plan, a long bowsprit, usually means a large headsail, you will want to avoid a lee helm, so take your combined or total centre of effort in consideration first.
A large headsail will put more stress on the bowsprit. To keep the sprit from turning, here are a couple ways to hold it steady. Both will let you loosen or remove the sprit when you want to break down and pack your model away for transporting. In either case, make the base of the bowsprit longer.

One way is to take a length of brass wire (supplied with kit), cut the ends at an angle to make them sharp, and work into the wood angling either inward or outward into the deck with pliers, read more about this method in making wire fairleads.

This will form a loop on the deck that the aft end of the sprit will slip into. Another way is to attach the sprit with the eye screw at the bow, and drill a 1/16" hole down through the aft part of the sprit and into the wood. You then tap a small brass escutcheon pin (a small brass nail) down into the hole, the pin has a rounded head and will not be too hard to pry out with the edge of a dime or a small screwdriver. The pin should be the same diameter size as the hole and not longer than the hole is deep.

A slot sawn into the end of the bowsprit, using a fine saw, can also be used, the pin stays in place, and the end of the bowsprit (or boomkin) slides into it.

A long bowsprit may also need extra support to resist the upward pull of the head stay, although the above methods add some extra strength, for extreme lengths you can add a sprit stay that will counteract the tension of the head stay. This method uses a line that is tied to the tip of the bowsprit and then runs underneath the bow. A little slice into the bow entrance will keep the line in place.

The stay is then pegged into the bottom of the first mast step with a short piece of dowel. The dowel should be waxed to keep it from sticking, and can be removed by pushing it back down from the top of the deck using a nail, stick, or what I use, a wooden golf tee with a flat end. (Works great!)

The boomkin is used mostly on yawls that have a mizzen sail that stretches back behind the stern.
The boomkin can be made from 1/4in. dowel too. We want to cut a section out of the end of the boomkin about an inch long. This will make it sit flat on the deck and hook over the stern to keep it rigid, (on transom models). Also, thin enough to screw it in place with the aft fairlead.
First step is to lightly saw across the dowel about half way deep, cutting in at a slight angle, the same angle that the stern has to the deck. (10 deg.)

You can split out the wood by placing it in a vice and nudging the chisel down into the end, but don't try doing it all at once, you should finish this job by rubbing the dowel along a file or some sandpaper set down on the edge of a board or workbench.

Measure and mark carefully where to drill the hole that the aft screw eye will run through. Then mark and drill another hole at the boomkin end. Into that end we place a small brass screw eye, make sure the pilot hole is big enough or it will split the wood! If you make your own out of wire, use some waterproof glue.
Then finish off the bowsprit or boomkin with either a clear finish, stain or tung oil.

Double ender model sailboats have two pilot holes at the stern, with some well placed pilot holes drilled through the boomkin, or by using the slot method described above, a pin or a small screw can be used as shown.