Paradox Catamaran

Discussion in 'Multihulls' started by Wavewacker, Sep 25, 2011.

  1. Wavewacker
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    Wavewacker Senior Member

    I'm sure you all know Paradox, that micro monohull Sharpie. Just wondering, could you take two of these boats and put them together with a deck, even a sitting height cabin?

    The reason I went there is that standing in Paradox the roof comes to about chest heighth, with a higher cabin above the deck, it could give standing headroom. As a camping type, one hull can provide room for the galley, the other for a berth and a sitting area on deck.....not much, just a minimal cat.

    I believe that Paradox is about a 42" beam at 15 and a half length....maybe run the hulls out to about 18', but the cat beam would not be half the length, more like 66%. Has this ever been done???

    (Something like Richard's Skoota, but the hulls are not living space. I'm not after the most efficient sailing cat, just the most livable small motoring cat with downwind capabilities )
     
  2. dstgean
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    dstgean Senior Member

    Once you get out past 10:1 length to beam, you lose much of the benifit of a multihull. Could you do a tri?

    Dan
     
  3. Corley
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    Corley epoxy coated

    My first thought was with 4 to 1 L/B ratio we are talking FAT not PHATT.
     
  4. Wavewacker
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    Wavewacker Senior Member

    12' beam and 18' length. I was thinking the cabin could unbolt and turn 90' and the hulls slide in to trailer at less than 8' wide. Yes, that may be fat.

    Absolutely Dan, there was a small motor tri that used tubes through the main hull to the amas and they were pretty simple.

    I'm not really understanding the principles of the tri I guess, it's the effect of the amas, floats or poras (I guess) some appear to provide bouyancy, some look like a ski simply stablizing the heeling of the boat.

    That tri used in Whale Wars was pretty cool, but I'd never have anything that big and complicated...but those appeared to stay in the water and seemed to have the engines. Smaller scale, I want a single engine, but if fuel tanks could go in those floats and they stayed in the water I could certainly go there. And, a displacement hull.

    If it sounds like I'm lost, I guess I am in a way, or put another way, I don't really care what it is, a cat or tri, but a monohull probably won't work until it's over 30" and production boats at 30' are usually too beamy for the road.

    Recently, I saw a cat I liked, it was a Katamaran Mohon (I think Mohon) it had high hulls for it's apparent length, sailed and motored, but watching the videos I could see it was not practicle as it was bouncing in the slightest wake on a relatively calm lake, a hobby horse. In drag racing they say there is no substitute for cubic inches, here, there is no substitute for length.

    OTH, I'm not going to go 60 mph, just a bit more than 6 mph.

    Sorry, I'm rambling. Dan, I need about 6' in length of floor area with 6' say 4" of headroom and bending over and crawling in bed is fine, need to get out of the weather at the helm, heated, cooled...etc.

    Corley, it can be fat, phat, skinny, tall or whatever at this point, it just needs to be functional, not the state of the art craft of the year, sail downwind as efficient as a PDRacer and motor as efficiently as the Tenessee, Bolger's house boat sharpie. If a 24' Tenessee with amas would work, that would be fine.

    25K is the budget, that doesn't mean find an old wood trawler that will need 25K in repairs as I am not a wrencher of engines, ready to go in good condition, turn key.
     
  5. Corley
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    Corley epoxy coated

    I'm sorry to be flippant but the question gets asked so many times that it becomes a bit tedious, monohulls aren't really designed to be "stuck together" with connectives to become a cat and when they are they just dont work in a satisfactory way. In the size range your proposing I dont think living space in the hulls is a practical proposition unless you like sleeping in a hull thats the width of a coffin (the hulls could provide some storage for light bulky items though). If the boat was 25 ft long then yeah you can have some decent berths and a galley in the hull.

    For a simple boat you could look at Richard Woods small Cats, Ray's Slider or my favourite little catamaran cruiser the Jarcat. The Jarcat wont go to windward with an F boat but give you a decent living space and load carrying capacity they are a very affordable and simple build.

    http://jarcatmarine.com/
     
  6. Wavewacker
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    Wavewacker Senior Member

    Corley, thanks, I didn't really take it that way, I know it would be fat and inefficient compared to the designs you mentioned.

    I like Slider and Skoota, but the is no living space in Skoota and I could sleep in the Slider hull, but I would be a bear in the mornings and there is no room for the girls either...

    Corley, I have been on this venture several months. While I admit I have unconventional ideas, I'm willing to suffer to get closer to what I really need.
    While my sailing technique would probably improve over time, I would probably sail downwind in favorable conditions, otherwise the motor is running. 80/20 maybe.

    I figure if I keep posting this stuff Richard or Ray will spill the beans and come up with something....:D
     
  7. rayaldridge
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    rayaldridge Senior Member

    I'm a great admirer of Paradox-- I even bought the plans, just to marvel at Matt Layden's ingenuity, even though I'll never build one.

    But I don't think I'd be happy with a cat version. For one thing, as others have said, the hulls are too fat to give you multihull speed, and speed is one of the great pleasures of sailing multihulls,--- even with such an under-rigged boat as Slider, it's fun to be fast(er).

    Another problem is that several Paradox owners have opined that the boat must heel somewhat to make use of the chine runners for leeway resistance, and a cat version would heel very little.

    I think that if you want a motorsailer, you would do better with a monohull design, because monohulls can carry more weight and have more interior room than a multi of equivalent length. They also have lower surface area relative to their displacement, which is a consideration if you don't mind the slower speeds of conventional displacement monohull craft.
     
  8. Wavewacker
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    Wavewacker Senior Member

    Thank you Ray, I know it's very good advice. With a stiff wind the Mississippi can be pretty rough for a small craft. I have seen days where I would not want to be out there on anything less than 40 feet.

    This is all about like flying an ultra-light aircraft, if winds are calm or gusts less than 7 to 10, you could fly, you are grounded at 15-20. If you need to fly hops across country and time means anything, better not go with a powered chute. Get a single engine fixed wing. Boats are safer than aircraft, I can swim, but I can't fly.

    So, my boat should be appropriate for the waters, inland waters, the ICW, near shore of the Great Lakes, rivers and shallows of the southern swamps.

    A stable living platform to me means practically no heeling, very little roll or pitch. 7 to 15 knots is very slow to me, but that seems to be an acceptable cruising speed, so I will accept that.

    While I'd rather not pound all the time, that will be part of it with any small craft, so I accept that as well.

    The Graet Loop, as I understand it, is about 1,500 miles, I do not want to spend 10K for fuel, the less the better, I see some getting 1/2 gal an hour at such speeds with a 10hp but I could go a little more.

    The draft must be less than 5 feet, but that does not really take me where I want to go (unless I use the canoe). Cats at a few inches are perfect to beach and get in the shallows. Few monos have the really shallow draft, but Bolger's Tenessee is acceptable, but it would not have the stability desired.

    Sailing is to conserve fuel and for a little enjoyment knowing I'm moving without a fuel bill. I have sailed Hobbies, if I need to heel and hike out, I'll put a sail on my canoe (which I would like to take). My vision of "my" motorsailor is purely functional to move, speed is not a factor, but it should go better down wind than pulling an anchor on Slider. The sailing performance of Slider will never be attained with what I'm wanting to do, I have to accept that as well. A small functional sail rig is desired, but if it ends up being a motor only thing, I may have to accept that as well.

    I conceed that Paradox was probably a poor example. :D

    Dan has suggested a couple times that I consider a tri-hull. There is a motoring tri on the forums here, an open boat that, again, looks like a sharpie with simple amas mounted on tubes. The other is Bolger's Bantam, but I would like a sleeker, fixed cabin, but that style would do as well.

    For the money, I would go after an old Carri-Craft, the 45 footer for me would be awsome, but it's hard to find and it would take real $$$ to go anywhere. A floating condo. So a small Carri-Craft might describe the goal.

    Maybe amas on a long sharpie like the Tenessee would address the roll issue, add stability at anchor and in some chop. I keep repeating myself in these forum posts I know. Can the amas be big enough to hull gear, jerry cans of fuel? Long enough to look as if they belong on a boat like that and not as silly as plastic coke bottles on a canoe? (lol)

    I have other issues in my life that will keep be grounded for at least another year, maybe 2, so it needs to be a very simple and rather quick build, if I'm going to build.

    Back to the cat, I think Jarcat has dinning and camping galley in one hull and berths in the other. So does Slider and Ray's post of that modified Slider is great, but I must have room to stand up and stretch somewhere out of the weather, I can't picture going 1,500 miles sitting inside all the time. It must also go in cold weather as well, so an inside helm is required.

    Again, I'm sorry this is so long and much has been repeated. There has to be some type of contraption that can fit these requirements, I don't think they are asking too much at this point.

    Again, Thanks Ray, I know you are working on a 24 footer, how is that going? Will you be able to stand up in the hulls? Will there be a small sitting saloon? An easily lowere mast and rigging? I'd like to see what you have or hear where you are going with it.
    The last option is buying a sailboat and turning it into a "Strawler" motored sailboat with a small outboard.
     
  9. rayaldridge
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    rayaldridge Senior Member

    I think you'd have a tough time pushing Paradox to 7 knots, even with a pretty big outboard. The nature of displacement monohulls is that they're limited to hull speed, which is based on length. A boat as short as Paradox just can't go very fast. Multis overcome this problem by having very narrow hulls, so can exceed hull speed much more easily.

    Fuel economy is related to drag. You might try to find a copy of Thomas Firth Jones' excellent book, New Plywood Boats. In it he describes a motor launch he designed, a long narrow monohull called Puxe. He could travel at 10 knots with a 7 horse outboard at half throttle-- pretty good mileage, I would think. He didn't have to fill the tank very often, he said.

    One great advantage that multis and other slim-hulled displacement craft have over planing power boats is fuel economy, so I think you're on the right track. But it's going to be hard to have standing headroom in a smallish boat, and still have cabins low enough for decent performance (windage is a big deal in that regard.) I won't have it in the new cat, except under the open main hatch. But standing headroom is a bit over-rated as an amenity, in my opinion. Under way, in rough weather, you'll be sitting down anyway, to avoid being thrown around. In good weather you can go on deck to stretch.

    The build is going okay, though a bit slowly at the moment. There will be several places to sit, a small galley, two good bunks, and at anchor, a deck awning can give standing headroom on deck, protected from sun and rain.

    How much build space will you have?
     
  10. Wavewacker
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    Wavewacker Senior Member

    Actually, where I got the standing headroom fixation was from some liveaboard and cruising forums saying you needed to stand sometimes just to keep the circulation moving, that sitting for three days of bad weather (cold, rainy, snowing, etc.) would be very uncomfortable. That if the standing area was just three feet wide it would do for changing clothes like a human.

    Your point about sitting in really bad weather is a good one, especially underway and I can always go on deck to do jumping jacks.

    Indoors, I have a space 24' X 14'. I have a swimming pool cover that is about 18' X 36' that could be attached to the back of the house or another out building and put a few posts in the ground (temps) and use some sheet plactic for the sides. I was hoping to build the hulls inside, then the decking and assemble outside, then the cabin and finsish work. I have stout ceiling joists so I could put in temp eye bolts on the hulls, hook on a hoist and raise them to flip the over. I also have some 18" X 24' steel ceiling beams (about 14 of them) that could frame about anything to flip a heavier hull, hopefully they would not be needed. There are about 16 4x6 posts 16' I can use as well. I just can't build a fixed structure for more than a year.

    Since the last post I have been glaring at Bolger's Bantam, the AS 29 and his Microtrawler. Pictures of Slider are embeded in my brain and I try to adapt those hulls with higher freeboard or sides to other cabins....LOL!

    I'm also lacking on shop tools, no band saw, planner, lathe, but several power toys with various blades, including a chain saw for my finish work! :D
     
  11. TDSoren
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    TDSoren Junior Member

    small motor sailing cats

    I've been playing with tying together a pair of narrowed Eeek! hulls to make a small cat that motors well. If you read up on Malcom Tennant's displacement catamaran hull theory, it seems to have an appropriate shape. My big question being how well would this sail without heeling. I'm also wondering if some planing could occur with low horsepower due to the straight run of the bottom aft. If not, maybe some strakes aft Ala Caulkins bartender, a wonderful boat at both displacement and planing speeds.

    Of course the big stickler in smaller sizes has been acommodation in 10/1 hulls less than 30' long with no flaring sides. there's the whole knuckle thing, but at what point does slamming become a problem if you keep the free board low enough for good sailing performance......

    Go dory with the flair, but there goes my straight run aft for good motoring performance.....

    Tom
     
  12. Wavewacker
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    Wavewacker Senior Member

    Tom, I don't know what you mean by "low HP", I doubt you'll get any planning at 10 hp, 25 maybe and 50 probably. A planning pad properly placed for the hull and hp would work.

    Knuckles are not a bad thing, if well designed, allowing more interior space and incorporating more strength to the hull while allowing more deck area connection surfaces....I would think. Any large accute flair not consistant with the hull design certainly has to be above the W/L (does that make sence?). I'm no engineer! I understand too that low bridge decks or low knuckles become very annoying at anchor with waves slapping them.

    Before I'm harshly corrected, I'm speaking of a cruising cat at slower speeds, flying over the water, you'll need to consider where all the air goes under the deck as well, lift, etc...I'm not an engineer!

    Some guy had a home built ply cat on Ebay for sale recently, didn't go for much, I think it was 18' X 8' and had really fat hulls used for storage only it appeared. It was more like a tall party barge. Point being, it worked for that family based on the pictures. It appeared the guy made the hulls the same size on the bottom as the top, no flair and the bow appeared to have no deadrise, just straight down, so it must have had some real rocker to get it up with a 50hp. I think I can do much better having been on this site!

    I can see how Slider is what Ray claims, fast and stable. I have to figure out how to get the cabin to fit over a portion of the hulls to enter them that will lift up, maybe rotate, and pull the hulls in for transport.
     
  13. TDSoren
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    TDSoren Junior Member

    Wavewacker, (2w? ;-)

    Planing wasn't the main emphasis behind picking that hull. mainly it was the minimal rocker/straight run that helps with higher displacement speeds. There was just some mild curiousity in my mind about at what point the flat/straight run would actually allow "planing" in the sense of Bolger's sneakeasy type hulls.

    Most pure sailing sharpie designs have quite a bit of rocker for low wetted surface in light air, good tacking behaviour, and a good waterline shape when heeled (i.e. avoid dragging a transom corner). with a cat this heeled shape is almost irrelevant.

    With a flaring side version I lose this straight run at the back and resign myself to basic displacement performance under power.

    Malcolm tennant claims the point where a planing hull form gives way to a high speed displacement hull form in efficiency is somehwere @ the 30' waterline length. I've been penciling some sketches @ 20' and 30' to accomodate what results from scarfing together 8' plywood. for a 10/1 hull that means either 2' or 3' on the bottom, and I should actually push that narrower if I really wanted to see some good displacement performance. That would push me towards the 30' length to keep any sort of real room inside of the hull.

    If I build a knuckle to get enough width for a good bunk, I need to make the hulls taller to make the extra width usable. This adds weight an complexity. or to simplify $$$$.

    I've looked at doing a central pod ala gypsy and such, but this again adds weight and complexity, as well as driving the sail higher at the foot.

    The place I want to use this boat is on the Columbia River around Portland. I currently have to wait for high tide just to get my trawler out of the marina because of the lack of dredging. I'm also tired of competing for dock space on the weekends. the thought of extreme shoal draft and just anchoring very close to the beach (not to mention going places where the motorized condos just can't go) is very appealing. There is also a chronic wake issue along with a short steep chop caused by the wind out of the west hitting the 1.5-3 knot current heading east, so a sharp entry is also desirable. when the wind is down and I have to get home against that current, good motoring performance is essential.

    If you've ever seen a Calkins bartender, it's a shallow V double ender with horizontals strakes at the stern. the straks give enough surface to give good planing performance while the double ended hull makes it an excellent performer at displacement speeds. This boat can keep punching along at 15-20 knots when many pure planing hulls have slowed to a crawl to keep from pounding themselves silly. Many coast gaurds adopted the hull form for life boats working the bars, Including the Columbia river bar which is infamous.

    http://www.bartenderboats.com/

    If anybody knows of a good 20'-30' shoal draft motorsailing cat with good acommodation for a couple for a couple of weeks let me know ;-)

    Tom.
     
  14. Wavewacker
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    Wavewacker Senior Member

    Wow Tom, I need to follow your build!

    That Timber craft is a nice one I like that. I missed a very similar boat in Little Rock that was for sale on Ebay, aluminum 28 footer that needed some work...an old CG boat...anyway

    You certainly have a better grasp of design than I do, but I'm wanting those steps at the stern as opposed to a double ender hull. But I believe that would be more efficient sailing, more canoe like. I don't know, I'm not an engineer.

    Knuckles or go beyond the 10:1 ratio? That is the question! LOL

    Does the flair at its maximum point determine the ratio or the width at the waterline? I have seen several that have a step or chine wider above the waterline increasing volume and I guess secondary stability.

    The bridgedeck from what I read should be about 28 inches, but many smaller ones are lower.

    The cabin and taller hulls to me is just necessary to accomplish the goal and making it as light as possible is probably the best you could do. If the trade off of having a cabin is two fat guys not going with you, then I guess they will need to stay ashore.

    My perhaps ill conceived notion is that a heavier cat with fatter hulls that provides good accomidations and provides more stability than a monohull and keeps a shallow draft is still a better solution for me. It could mean the difference between a 10hp and a 20hp outboard, that would be acceptable. If it sailed downwind with a simple rig, at 8 knots, that's OK with me.

    I mentioned elsewhere that there are some really good deals out there and probably will be for 2 or 3 more years. I can never build the quality in some areas of the production boats nor the luxury and finish, so for the money this may all end as a fluke anyway and might just build a Paradox or other small sailor for fun. It's hard to justify when you can get a 20 year old Carver in good shape for 20K!

    But, just in case, if I were to build, it would be a boat I'd keep and enjoy far more I'm sure.
     

  15. upchurchmr
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    upchurchmr Senior Member

    Wavewacker,

    There was an article by a European guy about converting a Soling (monohull - 30 ft I think) to a trimaran. It actually looked pretty nice, I've seen Solings for relatively cheap, the keel had to be taken off and something built in its place. The only way you would get it moved would be to dissemble the cross arms (akas) and outer hulls (amas) and truck it to a launching. The point is that 30 ft would make a nice boat thats relativly slender and could accept an outboard (not standard, but...) and give you enough room to be happy. Possibly even standup with a doger, but I don't know what was done on the original conversion. It won't please the purists ( including me), but you seem to be brave enough and determined enough to survive.
    Recently there was another guy in micronesia who changed a J24 to a tri which seemed to sail well and make him happy.

    If you want something easy to put a motor in with lots of room look for a Horstman Tri, they are often quite cheap.

    Good Luck

    Marc
     
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