Designed Finalized...........I think

After doing some thinking and taking into consideration all the posts here, I believe I have come to a final design. I am going to make my first hull a FKTF. Basically it will look as if it is a CBTF but without the canting ability. Seeing that my first goal was to create a boat that had the scale effect of Pyewacket, that will meet that goal. Secondly, it will cut down immensely on complexity. Thirdly, I have also decided that the twin foils will always turn opposite eachother, rather than worrying about collectivity and what not. So in short I will have a boat that looks fast and will probably be slower than any boats of similar specs. But once again it is not made for speed, just for looks and fun.

good plan. Are you putting a bowsprit on it?

I am planning on having a bowsprit. for this iteration of the boat it will also be purely visual as the fraction rig will be anchored about and inch or so behind the bow. I do have a good plug which in turn is going to result in a good mold as long as I take my time so this is going to somewhat of an experimental run, after which a full CBTF boat may result as well as the possibility of an assymetrical spin system utilizing the bowsprit, but that is A LOT of servos and complexity that may not be worth it. We will have to see. Thanks for the reply.
Andrew Miller

as i said in another one of ur topics, you can use the bowsprit to fly a larger jib that is still self tacking.That way you would only need the one winch or sail arm to control the sail. You could use that in light air. My boat i am building is going to have a bowsprit for light air, in which i will carry a sail that would be equivalant to a 150% overlapping genoa.

Thats not a bad idea. I dont know that for my purposes I will need the ability for a set of light air sails, but seeing as how most of my other hobbies have snowballed it probably wont be too long til im sailing competitively. I have been looing into possibly a CR-914 which is predominantly what is sailed in these parts. Thanks for your input.
Andrew Miller

on mine I am planning on having the light air genoa, and the full main sail in anything under 8 knots. between 8 and 13ish i will hopefully be able to carry full main and 100 percent fractional jib. Any more wind than that and i will start to reef both sails. If you set something off the bowsprit, you will want to make your rudder a bit deeper as you will suffer lee helm with the huge sail up forward. What kind of sail arm/winches are you planning on using?

I havent started to worry about hardware yet, as my plug will be ready to have the mold made over it by this weekend. Once I get the mold made then I will start to worry about those types of things. Do you have any recomendations? I am fairly new to RC sailing equipment but I have alot of quarter scale servos and what not laying around from my trucs and other things.

well, im on a tight budget, so i cant afford the digital servos, but I have found that Hitec makes great servos for a very reasonable price. All my boats have hitec servos, and they all work great(except for the ones damaged when the soling 1m’s leaked). Depending on the degrees of revolution, the 1/4 scale servos are good for using as sail arms, as they are extremely powerful. There are probably other people here who have more experience than i do with the different types of servos, so i bet other people will chime in with their opinions on brands/types.

Without getting too technical, what would an avergae sized rigs be for a 43" boat with a boom about 17 or 18 inches. Im trying to get a good estimate so I can start designing the rigging spars and what not. Thanks for the help.
Andrew Miller

i havent figured out exactly how much sail my own boat is carrying, but the hull is about the same size as yours, and im guestimating that in light air it will have about 1200 square inches plus or minus however much. Typical IOMs have around 600 square inches i think. Im not sure whether you are planning an oversized rig like i am, as my mast is something like 180 percent of the boats hull length. My boat is also going to have to able to reef down heavily, as it will get overpowered quickly. Hope this is helpful, and good luck.

After a little estimating Im guessing about 65 to 70 inches. Assuming about 900 to 1000 square inches of sail. The keel is going to be 15 or so inches with the two foils about 8 inches. Im mocking up the keel and the foils now so I should have pics later this week, possibly tomorrow. Thanks again for your input USA.

I have a 62 inch (about 1574 mm) mast on my 1 Meter multihull. In all, main and jib, she carries about 1100 sq. inches of sail (.709 sq. meters) as the maximum for the class. Boom length (main) is about 15 inches (381 mm) in length. No lead weight, but a 32 inch wide beam for stability.

The F-48 has a mast of nearly 75 inches, and carries 1400 sq. inches of sail area (maximum) with a beam of 42 inches. Again - no lead on or under the boat.

I am not sure of actual sail area for an IOM “A” rig - while the 36/600 is 600 sq. inches - but it is measured triangle inches. You get to add up to 2 inches for roach on main… and for the “M” Class, they say 800 sq. inches, but again, you need to look at how the sail area is being measured… triangle or full sail. Do they allow unmeasured rounded foot at bottom of sail? How much roach allowed on main and jib? Do they include mast and boom surface areas? etc. Same with the US 1 Meter and how sail area is measured.

A 5-6 foot mast on a 43 inch boat will be a pretty powerful rig, especially as the wind picks up. Canting keel will help, but you have to remember that the weight saved will also change load water line! Don’t forget to recalculate.

It amazing what a little boredom will do to people. I roughly mocked up the 2 foils and th keel. They are just cut out of cardboard so it obviously isnt anywhere near the final shape or position, but just to give a general idea. Also b/c I was bored, the hull hasnt completely cured in a few spots that I touching up so dont mind that either.

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