___'Try-1' _______________________________

- Some sailboats can be seen rigged with opaque sails, or with clear panels (like windows) sewn into them.
- It's a feature that has safety in mind, if you have ever seen (or been in) a race, you would be surprised at how close sailboats can come together. With everyone jockeying for position (full tilt) to get around a mark, that little bit of extra visibility, even if its just a vague outline of another boat, can help avoid collisions, especially when hiking over the windward rail with your leeward line of vision blocked by sail.

- I wanted to try a semi transparent sail just for the heck of it, so I rigged this model with sails made from a recycling "blue bag" that had a density, and weight of the plastic that was just right. (see choosing plastics for sails)
- The main sail is designed with a high aspect ratio. The head is supported by a long batten at the top that extends almost to the mast, leaving just enough room to adjust the draft. The other battens also are long, keeping the sail relatively flat.

- Another little feature added to this model is along the boom where the boom joins the mast. I found a bit of small copper tubing amongst the pile of junk (re. treasures) in the workshop. (I think it was a bit of old automotive fuel line.)

Using a fine hacksaw I cut a small ring, and after slipping the mainsheet line through, slipped the ring over the end of the bamboo skewer that was being used as the boom. Then, using pliers, I crimped (squeezed) the ring, fastening it firmly onto the end of the boom. The line runs freely through the ring, so the rig can still be adjusted.
There is no real advantage to all this, but I like the way that the end of the boom rests directly in line with the mast as opposed to sitting off to one side. You can buy aluminum tubing at some hobby stores that will also work too.

- I also added a few battens to the jib to keep it flat as well. (see pic) Keeping a jib from rising along the foot is always a challenge. There are different ways to do it, in this case I used a short batten as a brace up near the tack (weird eh?) but it worked!
- How much energy the sail foil lost in having the tack corner flattened out by the batten (where it doesn't generate much power in the first place) is regained by having the sail stay down and open.

- Along the foot of the jib is another sliver of plastic, cut a bit thicker than the battens. Acting as a boom, it is held on with a length of tape.
- The jib sheet leads up through a small jam cleat at the jibs clew, letting you adjust the length. This is a quick method, not as good as using a wooden boom, with the sails clew (and the jib sheet) run through a bit of plastic at the end. Using the quick way puts more stress on the sail clew, increasing the chance it could accidentally rip right off if the jib sheet is set up with too much tension.

The cross arms can be set up in a number of ways, in this case I used the pegs that hold the arms down onto the deck as fair leads for both jib and mainsail. The aft peg also pins down the brace lines keeping the floats (amas) in place.
- The rudder is deck mounted, giving the model an overall length of 18 inches.

With a multi hull you have more than one hull area providing lateral resistance, the area of the centre board can be kept small. The one used here is one half the width of a "stock" sized board, after sawing a wide stock board in half, you get another spare! (see fairing in your board)
- One more thing, most plastic drinking straws are white, the ones that I used to hold the sail onto the mast were rolled over a strip of brown plastic packaging tape. A strip of this tape 1-1/2" wide will wrap around a 1/4in. straw with just a little left over. Wrap the straw before you slice along one edge (to form the slot), then peel away the left over. The result is that unless you look real close, the mast looks like wood.

This is really our first model trimaran using the final version of the hull, (thus the name TRY-1) a few prototype designs were made before, the main 'bug' was coming up with a hull design that would balance buoyancy and lift at the bow, and still give you some "room" to customize the shape of the hull.

- The prototypes had a tendency to dive at the bow when driven hard. With a solid wood hull... mass = buoyancy, thus the slender MkIII hull would take a nose dive. So the hulls are made thicker(1-3/8in.), and given a ½" radius rounded edge at the bow as opposed to a 1/4in. like the other models. Plus there are is a slight upward slant under the bow (fore-foot) that increases the planeing surface (added in 2005 models)
There is still lots of 'bulk' left in the design for you to do your own customizing.

Enter a photo of your model in our sailboat contest and win a MkI kit. Visit our photo gallery, see pics of these models and more, plus, find out how get your own free online photo album! Post a comment on our message board!

- Although the sail plan is pretty aggressive, the MkIII could handle more area if you want more speed. Nevertheless, it sails well, and rates a 'Good' rating on all catagories.

Performance Rating:
Vertical Stability...Very Good
Windward Ability...Good
Swiftness...Fair/Good
Manoeuvrability...Good
Sail Adjustability...Good
Ease of Construction...Good

___'Pogo' _______________________________

Sprit sails have a thin straight spar extending from the mast to the sails peak. One small problem with this is that on one tack, the sail is pushed against the spar. This disturbs the shape of the sail, and the wind flow is interrupted, as it leaps across the dented area of the sail.
I designed this rig with a curved sprit, when the sail is pushed against the yard, it gives way, and the sail fills nicely to a full foil without any creases.

The spar is made with a steam bent bamboo skewer. Soak a few skewers in water for two or three days, make more than one just in case one breaks. (set it into a bottle full of water). After it has become completely soaked you can then start the heat bending. The heat source I used this time was the jet of steam that shoots from a whistling kettle. Don't have a kettle? Find a pot with a lid that has a handle that can be unscrewed, the steam will then shoot out of the hole in the lid . . . without all the noise   : )

Hold onto each end of the skewer and apply light tension to get it to bend. Don't be fooled by steam, the point where the steam shoots out of the kettle is extremely hot, so be careful, use as much caution as you would if you were using a flame. Also be patient, it will take a few minutes for the fibres to heat up and soften. Bend a full length skewer then cut it to the size you want.

The float (outrigger) was attached to the arms by setting the arms directly into the holes drilled through the float, this eliminates the need for bracing lines.

Keep in mind, the wood will swell when wet and the arms will jam in place when you do this. The model can only be disassembled after drying out.
* Arms that get broken inside the float can be tapped free by using the head of a finish nail.

The arms were cut to 8 inches long.
(I was experimenting on the effects of using different lengths) This set the float about four inches out from the main hull, about an inch more than if it were rigged as a trimaran. (with a 12in dowel) Note that the arms span right across the deck to keep it rigid. You can experiment with different lengths, the longer the arms length the more of a counterweight to the heeling forces on the sail.

On proas and outrigger types of sailboats you often see platforms spanning the arms, these are for crew to go out upon to hold the float down in brisk winds and for lashing cargo, also they are handy for slipping in and out of the water when you go for a dip.
- I built a small platform out of thin scrap wood, sliced into planks, then glued on two strips at each end to hold it together. (use waterproof glue) The platform is held onto the arms with a couple of lightweight elastic bands. (Easy) You can make your own using wooden tongue depressors, long stir sticks, whatever.

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