These hulls or not these hulls

Discussion in 'Boat Design' started by GMR, Sep 30, 2013.

  1. GMR
    Joined: Sep 2011
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    Location: Nova Scotia

    GMR Junior Member

    Hi,
    I have a pedal powered cat that I am still shaking the bugs from. I'm interested in building or assembling a trimaran that I can pedal and sail. My hulls are 18 feet long, 10 inches square, 5 inches rocker, flat top, semicircular bottom the entire length, weigh 45 pounds each, and have close to 500 pounds buoyancy each. That is if my friends weren't lying about their weight....... They are marine ply top and sides with cedar strip bottom.

    Is it worth considering using these as outriggers for a 20 to 22 foot long center hull? I will probably have them folding back for trailering.
    I did about 40 kilometers on this boat yesterday at an average speed of 3.5 to 4 knots. Clearly a bigger heavier boat will be harder to push and that will make sailing more attractive. This will be used in the North Atlantic around Nova Scotia but generally in protected waters.

    I hope I have attached two photos, if not my boat can be seen at

    http://gmrprojects.blogspot.ca/

    Thanks
    Glen
     

    Attached Files:

  2. rwatson
    Joined: Aug 2007
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    rwatson Senior Member

    Interesting concept.

    I missed the images of the props - are they proprietary ?

    Going on the videos, the speed is pretty underwhelming compared to the only other pedalling machine I have seen in operation. (around 10 knots ) But Rick Willoughby put a lot of time into his creations.

    The square section introduces extra drag - the profile of rowing shells is more where you should be aiming for. Weight is the other big problem.

    The longer the hulls, the better. Even if you have to make them 'splittable' to transport, longer is better.

    The big problem is that hulls substantial enough to sail, may end up being too heavy to pedal efficiently, depending on the size of the sail/mast etc.
     
  3. GMR
    Joined: Sep 2011
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    Location: Nova Scotia

    GMR Junior Member

    Hi

    I have benifited a great deal from the inovations and ideas of Rick and lots of others on the HPB thread. I am having great success with Rick's long unsupported prop shaft! The speed numbers they get are truly impressive! That being said, those were/are achieved by super light stabilized monohulls with just enough reserve bouyancy to allow them to carry a mouthful of water and a granola bar...and sprinting.
    The cat was designed to carry two people, 200 pounds each, with two completely independant drive systems, on the ocean in small swell, some wind chop and boat wake. With food, water, paddles, spares, snorkle gear, etc, all day cruising. I would certainly love to see more speed and the final version will have a lighter frame etc. The hull length was a compromise as usual, and the longest I could build in the basement and still get out without cutting in half. Although I have not finished yet, each hull can be used separately with small outriggers and I expect that will be much faster.

    Check out Rick's main hull shape on V14 which looks like a box but is really fast! See below for my hull shape.

    My monohull and cat versions will continue to evolve, but I am wondering if I can use these hulls as amas to a new 20 to 22 foot center hull? Or should I start from scratch? Some of the more modern looking trimarans have narrow deep section floats, flat sides, rounded top and bottom, vertical or even laid back bow. Some are biased to have more floatation forward....My brother in law has an Adventure Island and while I loved it and have been looking for a deal since, in this climate there would be few days that you could use it without a wet or dry suit. Too wet for for me I think.

    Prop for the day was an APC RC gas, 16 X 8. puts my cadence around 80-85. Slower than my recumbent bikes but feels good here.

    Cheers
     

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  4. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    Nice looking hulls.
    Why are you looking to go to a trimaran? Will you still have 2 people and the "expedition" equipment (snorkeling, food, etc?)
    Weight is the killer.
    Starting with the same 90# in outer hulls and adding a center hull will just increase weight significantly for peddling.
    Realistically you would be looking at even lower speeds.

    If you just want to sail as a trimaran everything will depend upon the sail area and width of the boat.
    Will you have enough sail area to fly the main hull or are you just going to use the outer hulls (amas) as stabilizers? Both can work, but as stabilizers those hulls will probably be heavier than needed. Those hulls look like they have more than 500# bouyancy at the deck line for a trimaran.

    What about making two trimarans with modest sail area by using those hulls as each main hull (just stabilized, not main hull flying)? Remember you now need centerboards/ daggerboards and rudder. The weight just starts mounting up. How thick of plywood and strip planking did you use.

    Great project.

    Last silly question. What about adding sails to your cat? 2 windsurfer sails with minimal staying might be simple.
     
  5. GMR
    Joined: Sep 2011
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    GMR Junior Member

    Thanks,

    I guess there are several things that attract me to multihulls, and trimarans in this case. I want to be able to go a little further afield safely. My previous boating experience has been 20 years with a sea kayak or numerous trips to the rail on large Coast Guard ships in storms. I do know that I don't want the rolling of a monohull....! Don't have much sailing experience yet but lots of friends happy to teach me. Plus I get to build something new! And I do want a drier ride. As far as being an HPB I realize I may have to compromise. Maybe with a hybrid system of sorts. Start with a fully charged deep cycle battery (s) and trolling motor, a bicycle powered generator on board to slow down the depletion. Solar panels to charge over a longer period. Since I am not able to retire for some time it would have all week to accomplish that!! I won't be happy sailing all day without some kind of work out. Which of course means I have to carry more food..........

    I don't think I am aiming to fly the main hull so they would more likely to be stabilizers. And the size of these would depend I guess on the sail area and width I plan to use? I like the idea of un-stayed masts, partly because this wilkl be trailered and I don't want to have to rig it up and down each time. Plus if I am using any propulsion mode other than sailing I don't really want it up. The AI Tandem is 200 pounds, 10 foot beam, 90 square feet of sail with an unstayed mast of 18 feet so that was going to be my starting point.

    You are right, each hull could be the main hull of a small tri, But I am looking for something bigger and drier. Surface temperaturer of the water here is only a couple degrees above freezing at the start of the year. I used 1/4 inch western red cedar strips and I can't actually remember the plywood thickness, quite thin...I will measure it this week. The attatchment points would need to be beefed up if used for a different application.

    My original plan was to add sails to the cat and I also have a kite that I would like to try.

    I wandered all over but hope I have answered a few questiond from both of you?

    Glen
     
  6. upchurchmr
    Joined: Feb 2011
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    upchurchmr Senior Member

    Looks to me like the current hulls could be used for stabilizing amas, easily.
    With the sail area around 100 Sq ft you will not be driving the boat heavily compared to beach cats.
    My major concern would be the weight creap with everything required to make it into a sailboat. Increased weight means increased loads.
    I would also suggest a stayed mast and water stays for the crossarms - both should reduce the overall weight and increase strength if engineered.

    Be aware that reports from a Cross 18 say that it is a wet boat in waves and at speed. Videos I have see show the bow wave coming straight up the sides until it gets blown back over the cockpit. Even if you have a trampoline to deflect spray in from the bow to the front cross-arm you sill likely see spray in waves.
    The Cross has a good bit of freeboard compared to modern boats. http://mysite.verizon.net/res78939/id3.html
    Take a look at the Trikala 19 by Kurt Hughes for a bow that might deflect more of that 0 Degree water. http://multihulldesigns.com/designs_stock/daysail/19_tri.htm
    Last I enjoy looking at these boats by Frank Smoot. Fun video: http://www.youtube.com/watch?v=C8kUq4BouS0&feature=youtu.be
    His website with a 19' and a 24' recent boat (at the bottom)
    http://www.diy-tris.com/2012/new-boats-n-photos.htm

    Sorry, I couldn't stop myself.

    I'm really interested in your project.
     
  7. GMR
    Joined: Sep 2011
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    Location: Nova Scotia

    GMR Junior Member

    I do love the way the floats move back and inside on that video! From an asthetics point of view there is something elegant about curved akas and the type that fold the floats under the main hull. On the other hand, if I am coming up to a steep or rocky shore, a dock, or another boat, I want to be able to pull the float to me. Makes it awkward to have tramps etc though.... I like the simplicity of sliding the floats in and out but I work in the oceanography world and sliding usually leads to jamming or seizing at some point. Rotary joints are easy to seal or keep clean but sliding is more difficult and sand will get on things one way or another.

    Interesting point on the spray issue. I have been doing a little reading about hull and float shapes where they refer to modern and older style boats. Seems the modern ones often have very vertical or even laid back bows and no flair at all while older ones ( especially those that use Hobie hulls for floats ) have quite a bit more. The newer ones are usually deeper as well, is this to compensate for the loss of flair?

    I bought the study plans for the Scarabe folding 16 and 18 which are possible builds. What do you think of those? Locally I can buy a Hobie Cat 14 and an O'Day 19 daysailor for less than 3 grand total, add another couple hundred for aluminum pipe etc and I have a serviceable "take apart" trimaran that I could have on the water in a couple weeks......!

    Lot's of fun! Thanks for your interest.....
     
  8. upchurchmr
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    upchurchmr Senior Member

    Typically a trimaran needs narrow hulls in order to get an advantage for 3 hulls.
    There have been other monohulls adapted as main hulls, which appear to have worked (try J24/ trimaran and Soling/ trimaran as a search on this forum) but the authors typically start out - I don't care about speed.
    Weight is the enemy, beam of the main hull comes with higher drag and weight. But it will work.
    You need to be seriously concerned about the connection of the crossarms (aka) to main hull, since there is a lot of concentrated load there.
    The issue about spray is generally more important on the main hull, since the leeward hull is farther away from the cockpit, and the spray blows away.
    Hobie 14 (or 16) hulls have a relatively small amount of flotation for their length.
    Check out the Dick Newick Tremolino which is much bigger, but used Hobie 16 hulls to start with. The design gradually got bigger outer hulls in order to sail better/ faster.

    I don't know much about the Scarabe designs. You might look at the Richard Woods Strike designs in the same length.
    http://www.sailingcatamarans.com/index.php/designs/27-trimarans-under-25/168-strike-18
     
  9. GMR
    Joined: Sep 2011
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    GMR Junior Member

    I don't care about speed!!!! Okay, that's not quite true.......

    The further I look into this the more designs keep popping up in the 16 to 20 foot range. My desires in no particular order,

    -21 foot max long

    -long open cockpit with room for two to pedal

    -folding amas (fore or aft)

    -definitely a human power component

    -small cuddy with low windshield and/or spray deflector

    -dry storage

    -dry hull shape. this could also be from extending cuddy outside hull edges.

    -quick set up. if it takes too long the boat will sit on the trailer more often.

    -relaxed feel, not a racer (although clearly it must fly past all other paddled or pedaled craft!)

    -good performance sailing up wind.

    -fairly simple sailing rig.

    -would prefer that the cross beams did not intrude into cockpit

    -would like to be able to sleep 2 people on board. Don't want a big cabin, but must be dry and off the floor. Must keep bugs out. I also need to be able to see ahead when seated and pedaling. as well as the passenger, nobody rides for free!

    -place to mount small motor

    -sailing instructor

    -weight is an issue.

    -cost......

    I bought a 1200# trailer for my cat so the wheels fit just inside the pads for the hulls. When I get to where I am going, I put a set of narrow plastic wheels in the ends of the frames and slide it off the trailer. This allows me to move it without the weight of the trailer. I can get it up and down any boat ramps or beaches so far. (clearly there will be many places this won't work.) Partly because I drive a front wheel drive car which will probably just spin on a wet ramp. And I will not be buying an SUV! I do however have a hook to screw into the front bumper for pulling the car out of the ditch and will be mounting a ball on that. Traction will be greatly increased in reverse.
    The other thing is that with a boat that comes apart I can take pieces separately down a path to the water sometimes. Driftwood is rarely an issue on this coast but boat launch sites are not as plentiful as most would like.

    I originally thought I wanted an unstayed mast with the sail furled because of the ease and speed of installation and fewer lines. But I am reading that these do not sail as close to the wind as a more standard set up? (excuse my obvious ignorance of sailing terms!)

    My idea of a marriage of cat hulls with a regular non-keel sailboat was just an idea to get on the water quickly because building a boat like this would take me quite a while... I have never looked at prices of used sailboats before but I am amazed at how inexpensive they appear to be. My fibreglass Seaward kayak retails for over 4 grand now and comes with nothing. I can get quite a decent day sailor with a trailer and two sets of sails etc for that price...amazing....

    Not as keen on the H16 hulls as I was, nor on using my cat hulls unfortunately. Looks like it will be taller and slimmer this time!

    Glen

    ps. There is apparently a Tremolino near here which I will go and look at soon
     
  10. upchurchmr
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    upchurchmr Senior Member

    Glen,

    Another relatively simple and light boat to check would be the Trika 540. Not a high powered flyer but looks competent for a stabilized, diy boat.
    I would suggest communicating directly with Klaus Metz, the designer.
    "Klaus Metz" <info@metzboats.de>
    For adaptation to peddle power, I have no expertise or suggestions.
     
  11. GMR
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    GMR Junior Member

    I have been looking at the Cross 18, Strike 18, Drifter 17, Scarab 18, Sea rail, Discovery etc and all seem to have potential.
    The yellow Strike 18 uses a Prindle 16 as a doner boat for floats and rig, seems pretty practical to me. Really don't like the flat surfaces on the front of it though. I certainly like the idea of a cabin to get out of the weather or for camping etc but I know I would not want it on all the time. So a two or three piece removable cabin might be the answer with a permanent ring to support the mast foot and the front arms, flared out to the shape desired for a cabin. I could have a cabin section from close to the bow, back to seal on this ring. Then another section from the ring back a few feet. Not sure about the rear arm support. Another ring here would be a pain I think. Rings could be made from laminated ply or I could easily use aluminum. Closest Prindle 16 for sale is at least a 12 hour and 300 dollar drive away although someone did offer a 19. Too heavy for me I think. I may want to fold the floats up on the trailer......suppose I could rig up a simple temporary clamp for the mast to pull them up......could certainly design a crank that would lift them both at the same time but the overall weight would increase quite a bit.

    I read that a few people have been taking existing hulls and floats and modifying them to achieve plumb bows.....is that really necessary or practical? They do look nice but anything even remotely sloping back would increase the likelyhood of becoming an involuntary lobster fisherman around here. Little trap floats can be hard to see when in chop or going towards the sun.

    I had originally planned on putting a sail on the Chameleon but my seats put the current center of mass just behind the center of bouyancy. Adding any mast would bring those pretty much in line and I can't easily move the seats back to put more weight on the stern. It would be just a main sail furled around the mast anyway so a small rig. Still, I don't want to end up on my head, especially with an audience!

    Float placement seems to have all three bows pretty much in line on modern boats, would you agree?

    So adding any sort of forward structure or temporary cabin to any of these hulls in the 18 to 20 foot range that were not designed to have one, is going to have some affect on the personallity of the boat. Any ideas on what I may have to do to counter that? Or how receptive the original designers might be discussing this topic?

    And what about the substitution of doner floats, rigs etc, sure save me a ton of time and probably money, but ,will it change the handling that much.......on the other hand, with no sailing experience, what ever the result is will feel right.
     
  12. rwatson
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    rwatson Senior Member

    It looks to me like you are well and truly into the 'requirements inflation' part of the design cycle - adding more and more while it does less and less of what you started wanting it to do.

    If you are really wanting to keep pedaling, 21 foot is a good size for speed, but its going to need to be something like a skin on frame for lightness- ( ballistic nylon and polyurethane coating ? )- with Kayak style seating and shelter in each/or one hull. You can still add useful sailing capabilities a-la windsurfer size rig and drop down leeboards and rudders without making a 'monster'

    I think you are about to build another one of a million fibreglass 'off the beach' mulithulls that will always be wet,cold and too heavy to pedal productively - except yours wont sail anywhere near as fast with a 'fairly simple sailing rig'.

    check out
     
    Last edited: Oct 13, 2013
  13. upchurchmr
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    upchurchmr Senior Member

    Watson has a very good point.
    You have a good HPV boat.
    Buy or build yourself a reasonable sailboat and don't expect one boat to do it all (well).
     
  14. Tiny Turnip
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    Tiny Turnip Senior Member

    Hi GMR, haven't got time for a full response now, but will try in the next couple of days. I have build a very similar pedal cat to yours, with two drives, which is on the big pedal powered boats thread. I also have a 16ft camp cruising tri - recently posted as Solway Dory trimaran on the sailboat section. I have been tossing around the idea of combining the two, possibly as a biplane ketch cat. For me, the limiting factors are weight in terms of man handling on the beach - the Dart 18 hulled, plywood decked pedal boat is more weight than I want to drag about on the beach already, even with two people. On the water, I'd definitely say that windage was the limiting factor for the low power of a dedicated pedal boat, but if it is auxiliary power to sail, that's a different question. I wanted to be able to sleep in hull, with a deck tent, and then have the option of moving seats from the hulls (sailing position) to the deck, and dropping in the seacycle pedal drives as a no wind option. I feel that weight is going to kill it, frankly, and if not weight, complexity. I'm still exploring it, however, and I'll try to post some of the sketches I've done.
     

  15. GMR
    Joined: Sep 2011
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    GMR Junior Member

    The dreaded all purpose vehicle, does lots of things and none of them well.....I do have an HPB that I am mostly happy with. The idea of human power on a sailboat would really be for calm conditions, I know a decent breeze might have me going backwards. Most summer days here start off calm with a significant on-shore breeze coming up by noon. But since I am a very early riser that gives me several hours where I will need something other than sails to move the boat. I do want a trimaran that sails well so I will build/buy/assemble a proven design from plans/parts etc. If I can't get it to move by my power alone then I will move to plan B or C. But I will end up with a safe and reliable sailing trimaran. Can't promise that I won't change a few little things........

    Hey TT, I see your red cat is still going well, very nice tri you have there! Beautiful boat. Do you mind me asking what it weighs now ready to set sail?
     
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