Any one know about Plans/Designs that can be purchased for F14 Stitch-N-Glue or composite over foam and stringers might be ok on a small boat like this too. Preferably a modern design.
I was just looking as i want to build something small light and fun to race + solo for regular recreation. i am like 5'5" 150 lbs\ and want something i can handle on my own.

Thanks for any help.

Also anyone have an opinion on the quattro 14?
Sail one raced against one its ability to race competitively? as this is the only plan I have found so far.

I've been looking for the same thing - I'm even considering designing one myself. I've been looking at the Moths and International Canoes, and I'm starting to think that a 14 foot, 140 pound canted daggerboard planing cat might be a solution to the issue of reduced speed with reduced length on traditional cats. Semi-hard chine hull like a lengthened Moth hull. With carbon-reinforced Okoume and carbon beams/mast,I think it might be do-able.

I'll keep you updated if I get anywhere with it.

I would build a Paper Tiger before I built a Quattro.

Yha I did not even like how the thing looked but was fishing here. I am considering doing a 16' also but would prefer an 14 i think. I wonder about if you were to take the measurements of say the 16' Blade and just scale it back to the 14' rules. But I am a noob here and just starting research.

Apart from the older “established” 14’ cats (most, if not all of which were designed for ply and dating back several decades), all of the, so called, “performance” hull designs for 14’ cats (and most other sized ones as well) have, through necessity for their performance, “compound curves” in their hull shape that make their manufacture out of ply virtually impossible. There is just so far you can “torture” ply before it fractures. This means that if you were to “home build” a set of 14’ hulls, the only options that you have are to go with the less efficient, older style ones.
I suppose it all boils down to just what you want from the cat that you sail on? If it is just to get out there and sail/race, then it doesn’t really matter what you sail if you race only on handicap or in a one design class, but if you are looking for the “latest, fastest” performing F14 (or F16) in the world, first start with a set of hulls that you know have the potential.
I am sure that most if not all manufactures of “high performance” 14’ and 16’ cats will sell you just the hulls and then the rest of the build would be up to you

part of the reason I've been looking at the possibility of a planing cat has to do with the ease of building hard chines with marine ply, versus super-narrow round-chine displacement hulls.

Planing on a large cat with lots of waterline has diminishing returns. But at 14 feet, I think it might be reasonable. If the McKees could build a planing cat 20-30 years ago with surfboard blanks and all-aluminum beams/mast, and a crappy sail, I think we ought to be able to do it with carbon and canted boards to add lift.

You're right, it has to do with what you want - I like the idea of two modified (enlarged)Moth or IC hulls with 8' of beam, canted boards, T-rudders and a chute.

michael C
I have wondered about the planning cat idea myself...Designing and building high performance sailboards since 1986 I can't see why some of the hull design learned from that venue couldn't be incorporated in a small cat...even sub 14 foot. After all if we can go 30 mph on a 8'-4" sailboard why couldn't a hull be made with two modified boards and achieve at least current cat speeds? I know someone tried it once with a kind of catamaran sailboard hull with a hard deck...don't know how successful it was...but one try does not prove or disprove the concept. Definitely takes thinking outside the box...

Regards,
Bob

http://www.mckeewildthings.com/video/itza.mov

The link above is exactly what you're talking about. 25 years old, a bit ghetto, but the idea is sound. A planing hull out of 4mm ply, with modern tech, and real hulls (albeit very low freeboard) might make a boat lighter than an A-class that could be built for a couple of grand and that would be an easier build than the tortured ply narrow hulls. Four feet shorter boat, a shorter/cheaper mast (maybe even pocket luff), all seem interesting.

When I get a chance, I'm linking this on Bateau.com - maybe the designer there would be willing to put out a set of plans. Long shot, but...

Anyway, if you download the freeware for Hullform (design program) I'll send you the design for what I have in mind.

Interesting...so it has already been done in a primitive way...I was thinking if you could make the hulls pivot at the beam attachment points so that the leeward hull could stay flat on the water as the windward hull left the water. It would make it a lot faster...seems from the video that he is cooking along nicely until the leeward hull goes from flat to angled, which is no surprise since the fastest way to sail a sailboard is keeping the hull flat as possible. Now if you could some how steer the craft with modified sailboard fin and get rid of the rudder and centerboard it would be even better/faster. It is a huge rush to be going 30-40 mph on a sailboard standing up…if you could approach those speeds sitting down, with the water so close….it would be unreal.

Michael why use plywood?...Why not make it out of Styrofoam/Divinicell/epoxy just like windsurfers? You won’t be limited by the bending ability of the materials and it will be super light. A 9’ slalom board is sub 15 lbs. As long as you are not going to have too much hull volume it would be a viable alternative.

Might have to form another forum heading for cats 12’ and under…LOL

Regards,
Bob

$ <img src="http://www.catsailor.com/forums/images/graemlins/frown.gif" alt="" />

All joking aside, the reason for ply was that my designs I've been playing around with have been somewhat more traditional (in the loosest sense). Really good 4mm ply taped with carbon is the best material I can afford on that scale. At 13 pounds for a 4x8 section, it's not too much heavier than the alternatives.
If it works, then I'll look at the pricey stuff, and just swap the rig.
I was thinking of heavily canted boards to convert heel to lift, should solve the excessive hull-flying and let it plane easier (semi-foil). Somewhat more traditional hulls would also be less affected by slight heel.
I'd even considered using the longest windsurfing fins I could find for rudders.

Of course, you could just shape two 12' paddleboard blanks, cover with epoxy and carbon, fabricate 2" x 8' carbon crossbars, raid a 12 meter windsurfing sail, add a layer of carbon to the mast, use skegs for rudders and daggers, and be in the water really quick - don't think I haven't considered it <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />

I've already done it. I have the machine laying in my yard behind the shed. It consists of two glassed paddle boards for hulls with a 'Hobie like tramp/frame, the legs of which have pivots at the base to allow them to maintain a flat attitude. It has a big sailboard rig with fixed wire side stays, a wire forestay with bridle but with a big bungy to allow fore and aft rig angle adjustment by a std mainsheet off the wishbone, for steering like a windsurfer.

Didn't work because the side thrust on the fins cranks the hulls/boards, over on their side.

I was going to try wings from which the legs would reach the hull sides to offset the tendancy but it all got too hard and I abandoned the project.

good to hear the results - makes me feel more certain the double-moth style boat in ply is the way to go.

Anyone try two windsurf style hulls with an extra wide beam to keep the hull flat?... with two windsurf rigs similar to the tri-foiler? If you can generate the speed...who cares if you "fly" a hull or not?

Regards,
Bob

Darryl would you consider giving us an idea of how wide (at the widest point) and how tall (from keel to deck at its deepest point) the hulls are on the Alpha Omega? I was watching you DVD again (for the gazillionth time…by the way Thank you! again) and it looked like they were maybe 20” tall and about 8” to 10” wide…can you give us the real dimensions. Any insight would be greatly appreciated.

Also since you have had the opportunity to sail your boat for a while, would you consider less tail rocker? I notice the boat pivots around nicely on the boards but wondered if you could keep the great tacking ability while decreasing the upward angle from the boards to the transom?
At least in the video it never seemed to misbehave to the point that you had to move back far enough to use all the tail rocker…I do acknowledge that it is hard to get a complete picture of what is going on by just watching the video. I look forward to your comments…

Regards,
Bob

Hi Bob, the approximate dimensions of the Alpha Omega F14 hull are 8” wide at its widest point on the deck, 9.5” wide at it’s widest point on the bottom of the hull, and 17.5” deep at it’s deepest point. The term “rocker” is used by most people to describe any and all directional “shape” change along the horizontal line of a hull, but that can be a little misleading as not all directional changes act, in the true sense, as “rocker”. The aft rocker on the Alpha, as you call it, is in reality designed to release energy at, or near, the same percentage rate that has been put into the water by the entry of the hull.
When the bow “parts” the water it displaces a certain amount of water starting at zero at the bow, and gradually increasing that displacement all the way to the hulls maximum width/displacement point. The displacement is then relatively constant until there is a release of that “energy/displacement” towards the rear of the hull. An ideal scenario is to release that energy at the same rate and in the same way that it was put into the water thereby creating a very “clean” transition through the water. Unless the hull is double ended it is impossible to release that stored energy in the same way as it was put into the water. I.E. the bows are fine and deep and the transom is not. Therefore that energy release is primarily obtained by the underwater transitional shape of the aft section of the hull to the transom. That is as simply as I can put it without going into some very complex mathematics. What most people refer to, as “rocker” is simply the curve put along a hull bottom to allow it to tack easier than it would if it was a straight line from the stem to the stern of the hull bottom. Strangely enough a lot of boats are designed with little regard as to where the rocker is placed for maximum efficiency but instead are only concerned with the actual amount of rocker for a given hull length and displacement.

Hi Darryl…thank you for sharing the dimensions of the Alpha Omega...as well as the explanation why you have the hull transition from a relatively flat rocker line to the relatively steep angle from the boards going aft to the stern. I used the term rocker for lack of a better descriptive phrase.

You stated “That is as simply as I can put it without going into some very complex mathematics.” “If” you have the time and inclination, I would really like to know more about how this is calculated and get a deeper grasp of the concept. While your explanation is very clear in describing the reasoning behind this design feature, it leaves me wanting to know how to calculate it for a given hull design…I appreciate you sharing your knowledge on this subject.

Regards,
Bob

How are you at polynomials, matricies and calculus??

Darryl can't claim those are used in my everyday life… but my father law is a senior design engineer working on the next generation Space Craft to replace the Shuttle program. My wife works at United Space Alliance in the ground support design engineering group out at Kennedy Space Center. So I would hope I could find someone to help me understand any area that I might be lacking…LOL…

I do have a working knowledge of Block Coefficients, Prismatic Coefficients, Water plane Coefficient (coefficient of fineness) and curve of areas. How much farther does your method take it beyond the curve of areas? If I am following you correctly you are taking about minimizing eddy making resistance at the transom.

I have often heard that the wise surround themselves with great minds….I try to work in that direction… thank you for all your help Darryl…

Best Regards,
Bob

There is a relatively simple way of looking at the subject Bob.
Look at the volume displacement of the hull, from the bow back to the maximum displacement and the rate at which it is increased from zero to its maximum, Once you have that then you look at the many various ways at which you can “release” that energy cleanly. Looking at it in this way should guide you to the required calculations in their simplest form.
Remember that the displacement energy is "placed" into the water in a global fashion, it cannot be looked at accurately in a two dimensional calculation

Thanks Darryl, the way I was taught to use a "curve of areas" accomplish what you are proposing in 3 dimensions...I just never thought about it when looking at the steep angle most cats have leading up to the transom... I was hyper focused on trying to get more boat in the water to minimize pitching (which you are addressing with the t-foils on the rudders)...and while doing so I completely lost perspective of the eddy making effects. I feel like a mechanic who has had a tool in his box for years and needed someone to come up and remind him what it was really designed for...LOL. Thank you for the insight.

Regards,
Bob

Does your father in law work for NASA Bob? Isn’t that the place that makes the most technically advanced and difficult pieces of machinery from suppliers offering the lowest quoted price?
Always seems to be an oxymoron to me, sort of like “military intelligence”, or “honest politician”.
I think if I was going into space sitting on top of a massive “controlled” bomb, I would be more comforted in the knowledge that none of the contractors who supplied the many parts under my bum, were the “lowest bidders”. I would rather they were simply the best, regardless of the cost.