Trailerable Multihulls

Discussion in 'Multihulls' started by JCD, Mar 4, 2008.

  1. JCD
    Joined: Jul 2006
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    Location: Coney

    JCD Follow the Bubbles!

    Hello Richard and welcome back…

    It is always a pleasure and honor when you spend valuable time to share your thoughts in my humble thread. Thank you. A lot has happened since you last visited, so…

    I try not to participate in flamed threads because it can be distracting, but sometimes I have to because there is a lot of brain muscle that contributes excellent information and like yourself, get discouraged and stop doing so. This is a loss for all of us. There are times when anyone including myself can have a meltdown...that's human, but when it is persistent, then someone needs to be the bigger person and stop. I have always believed that we can agree to disagree and oftentimes solicit hard opinions and advice, but I would never consider that receiving it is disrespectful. I don’t censor thought or speech and I will hope that everyone participating in this thread believes and proceeds the same way.

    I believe the similarities are coincidence but I also am pleased that you would think that I would use your design as the basis for my own design because if the Green Lantern had not existed, I may have done it and with pride. The design is an evolution from my Green Lantern which I scaled and, changed the profile a bit to reduce some wind-age and volume at the bows. The underwater form is identical to the Green Lantern’s because I believed it to be a superior form (superior as far as my design capabilities are concerned without sounding braggish).

    The cuddy is a result of wanting a cabin on deck for “comfort” in inclement weather as it appeared that we both agreed it was a must for offshore cruising. Meanz Beanz produced some photos of your design and the rest is history. Right now it is just a box to test the folding concept, but eventually it will be streamlined and trimmed up. Visibility will be a must. Have you noticed how little of it is above the hull profile?

    Yeah…and if I was Richard Woods developing the design, I would have also, but I don’t have that kind of experience or expertise to be able to multi-think all of these new concepts and I’m trying to keep a paced systematic and methodical way of advancing them so I don’t throw the computer out of the window. No twin rigs. I don’t consider the Aerorig good for the design. What do you think about a balestrom or free standing? The genoa, mast beam and all other components will be in the very near future. It is on my to do list but right now I’m trying to take a swing at all the curve balls before trying to home run a fast ball.

    Mast compression loads are still up in the air right now because I have looked at scaling the design to 27’ and that will add some displacement. The depth is not really critical because the beam will be inside the cuddy and on top of the hull’s cockpit so even if it was 18” deep it can be used for seating. The interior layout is still murky and I suspect it is as such because of everything you have just pointed out.

    The dagger boards will be non-intrusive. I know…somebody stop me. I have once again looked to explore another precedent. Not sure if it will pan out, and I sure hope it does, but you will find the rough idea on the attachment “trailable concepts” below. Further development may find the hull with a small foil skeg forward to protect the dagger when retracted. It is a dagger/lee board hybrid.

    I’m trying to keep all these concepts on paper as soon as they come to me so I don’t forget. Again, these may or may not happen and may require extra thought and possibly extra engineering, but if we can get a man to the moon and see the results of a star that exploded before the earth was formed…then I can see this and engineer it to get there. Although I am being humorous, I am serious.

    That is exactly why it is imperative that the design be capable of providing a comfortable and safe home on wheels. Many avid catamaraners will love knowing that she is offshore capable, but more than that, there will be those that spend significant amounts of time on the road getting to a large number of bodies of water with huge road distances between them and they will love it even more knowing that like a motor home, they will have their “home” with them so that they don’t have to pay premium for a room in a hotel with ice available in the hallway.

    I am always amazed of how we are capable of manipulating the forces of gravity and buoyancy. That whole set-up is clever indeed. I have only been able to master the sideway forces of push and pull with the design thus far. With little leverage or limited strength, I guess some kind of electrical or hydraulic mechanism can be used to open and close the trailer wings, but that is definitely not as energy efficient as gravity and buoyancy. Float up and drop down. Amazing. To my own credit, I have been giving some thought to folding her on the water for narrow ramps, but think it will take some type of multiple-gear high-load winches due to possible binding or high friction. Not sure until I can figure out how stiff the beams will be. I’m shooting for 1/720 of span under heaviest conditions.

    I also hope to design and achieve this advantage. If I can’t surpass however, I at least hope it will be easier than suspected from first impression.

    Great motivation! Everything you have mentioned thus far was giving me the impression that you were pushing me to think and work harder and faster on the concept. Now I believe it!:D

    I regret, for me, that the design has only 6’ of headroom with no sole because it is not high enough and a sole is always nice no matter how narrow. That was a necessary evil to avoid as much windage as possible. The 27’ scale up gives an additional 3” of headroom and actually reduces windage percent. Headroom is not an issue for the first mate in either of them. However, she will rave like a maniacal lunatic if a “proper head and shower” are not available. Even on a cruise liner. Needles to say, I buried the aft bunk 4 feet under the cockpit to provide a very generous head/shower in the design.

    I have not doubt that you both deserve to have 2 or even 3. However, not everyone is thus graced or has that type of energy or resource. I will expend significant energy to produce a design that will provide everything that could be minimally needed or wanted in 1 boat within reasonable expectations.

    I, like almost all others, want a bigger boat. The reality is different. I don’t need a bigger boat than the smallest boat I need and I believe the same is true for everyone unless, you want a bigger boat than the smallest boat you need for the purpose of wanting. Did that make sense? Transportable is good and in a sense, trailing is transporting, but trailering is a must for this design because I believe there is a huge gap which may be in high demand since no design exists that is “offshore rated trailerable catamaran”. I will change that with this design.

    Indeed you have said it before and you still sound as adamant as before. I have no choice but to accept that your experience may qualify your statement as “highly probable and possibly true if you refer to multi-hulls.” If that is the case, there is no argument or discussion from me.

    Within the design constrictions, I agree that the 26’ or 27’ design will not rate Cat A as a trailerable or any other form if it is to be lively. This is obviously based on the results which have been generated form calculations and rules derived from generally accepted guidelines that offer a specific rating within certain boundaries. For or against me, I do admit that there is a significant possibility that I do not have all the required information or have interpreted it incorrectly.

    I cannot concur that a Cat B for my design is pushing it based on the information that I have privy to my person and utilized to measure the design. In fact, both the 26’ and 27’ have already met Cat B guidelines and scantlings and rig guidelines are also met along with other performance parameters. Indeed, the results denote an excellent performer with excellent wetted form. Again, I do admit, for or against me, that I may not have every single rule that may be required to calculate a true final number.

    I am completely open to your qualified definition of a true Cat A, B, or C rating as generally accepted and I am willing to introduce any new information into the calculations to measure the design.

    I would be very interested and grateful if you took the time to disprove the results as I do not want to propose an offshore capable Cat B if it isn’t. Yes, I said disprove. In fact, I offer this request to anyone willing to act upon it. (Consider it a challenge if anyone wishes to) All that I ask is that it is a qualified, accepted test which the design will fail and that if it was not information available to me, then it will fail only if I cannot redesign and pass the test.

    However, until such time that the results for the design rated Cat B can be disproved, I remain confident that "no design exists for a trailerable catamaran that is offshore rated for Cat A or B" and not only do I continue to contend that the design has already met Cat B status but continue to design as a Cat B. It may even be a possibility that no design exists for a trailerable Cat C catamaran, by design. “By design” being the operative word in all Categories and for all trailerable catamarans.

    I am attaching the “trailerable catamaran” hydro and other results for perusal and for those whom would like to disprove the design as Cat B. I have included information for both the 26’ and 27’ in light displacement (minimum for inshore cruise) and heavy displacement (maximum payload included) If I can offer any other information to assist you to disprove the results, just ask and it will be provided if available.

    I have generated scantlings in DuraKore and glass skins for both, with the exception of beam and mast since those have yet to be decided.

    Thank you for reading, but please continue to contribute. I have always found your contributions very generous and helpful.

    As always, I have and often do so.

    Thanks
    J:cool:
     

    Attached Files:

  2. Richard Atkin
    Joined: Jul 2007
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    Richard Atkin atn_atkin@hotmail.com

    J, you really need to back off a little with the *** kissing!! :p
    I like a lot of Richard Woods designs and don't deny he is talented, but he is not God. :D Besides...none of his designs are as good as mine.

    Just one question. Does my design qualify as a category C? Or would it be called a party boat?
     
  3. Kerry Thomas
    Joined: Jan 2008
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    Kerry Thomas Junior Member

    Trailerable NZ coast multihull

    You may like to look at www.altairmarine.co.nz. Clamcat. The boat was designed originally with a smaller rig for the NZ coast. Offshore almost anywhere else.
     
  4. JCD
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    JCD Follow the Bubbles!

    Hello Mr. Thomas...

    This is an unexpected pleasure. Thank you for contributing and thank you for the reference. Unbelievable as it may sound, I did not find that design in what I believed to be a thorough search. It is an excellent design which I find quite interesting.

    I see that my latest thinking about folding horizontally has already been tried and tested with the only difference being that your design folds the cuddy over the hulls instead of into the cockpit. Is that accurate? Has it been reported if binding is an issue? The link to the build was not working.

    As you have obviously already read in my thread, my contention is that no "trailerable catamaran rated for offshore use exists", with more recently narrowing the varied definitions for offshore to Cat B. However, in the interest of providing benefit of the doubt, I will be objective in studying the designs offered to disprove my claim.

    You have pointed out on the site that it is designed for "local inshore racing and coastal cruises" and that the "configuration is ok for offshore minimalist cruising". Had the latter not been on the site, then we would have no need to explore it further although the above is pretty clear that it is not designed as I claim. Establishing if the design is rated Cat B is much more important for me to explore than the configuration being "ok" for offshore use.

    The definition is unclear to me and I don't know if you mean the "layout configuration" or the "design configuration" qualifies it to be offshore rated. I have checked the site and find very little information from which to measure the design.

    Would you mind sharing some basic information that I can use to input into a spreadsheet to establish if it may in fact be offshore or Cat B as a matter of consequence instead of by design since you have already pointed out that it is not designed for offshore rating? The list wouldn't be very long and definitely not anything that could be considered a hijack to the design. I would be happy to provide all the results to you publicly in this thread or privately.

    Two thirds of my claim have already been disproven by other designs, (trailable and catamaran) as has this design, therefore, notwhithstanding that it is designed for local inshore racing and coastal cruises as you point out, I would be willing to explore it further unless of course you maintain your current position that it is designed as inshore and coastal but not offshore or Cat B.

    Thanks

    J:cool:
     
  5. JCD
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    JCD Follow the Bubbles!

    Hello Richard,

    Ouch...although unprovoked, I forgive instead of attack you because you cannot truly know my person in this faceless forum of acquaintances. I am not an *** kisser as you point out.

    It is a pleasure and it honors me when he and anyone else takes away from their valuable time and contributes their thoughts in my feeble but humble thread. The same is also true for you. Often times truth is misconstrued as something that it isn't just because we read to much into simple things like courtesy.

    It is unfortunate that your opinion of me is that I am an *** kisser since I had believed that there was an understood mutual respect for each other to share ideas and opinions instead of insults. I have always believed that I was courteous instead of an *** kisser. I say hello when I come in and greet everyone and I say thanks when I leave. I regret that I may have acted in a way that has given that false impression of me but sticks and stones...

    We're in full agreement that we like his designs a lot and that he is very talented and not a GOD, but I fail to understand whether you are giving him public praise or if you are just overstating the obvious without any point to be made. Please advise.

    Boasting about your design is a good thing. I do it but I can't really remember pointing out that it is superior to others. It is however a good idea to re-think and you may even want to re-state your position considering the competition you challenge and his accomplishments. Indeed, you may wish to re-consider it permanently considering the company you're in within this forum.

    I never really thought about whether your design was rated because you never made mention of designing it as such. I would be inclined to liken the design to "sheltered or protected waters" because of the number of persons you intend to host, and that may be my own paranoia, but I believe that coastal or inshore is a definite if you sail in fair weather and keep crew down to the smaller numbers. If you use it the way you claim, I can definitely say it will be one hell of a party boat.

    If you like, I can run it through the spreadsheet and provide you with the info that it produces. I need some basic information and I'll attach it below in case if you want me to try. It will also produce other performance figures which will help you assess the design and compare it to other designs more confidently.

    Have you been following the thread and checking all the current concepts I'm generating? :D

    I really think that this "design rated trailerable catamaran" will open up doors to many avid catamaraners looking to take "the long" cruise with confidence in knowing it is designed and built to a rated category right from the design stage and not as a consequence that can become a dangerous variable.

    Thanks
    J:cool:
     

    Attached Files:

  6. Richard Woods
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    Richard Woods Woods Designs

    A quick reply as I'm supposed to be working today.

    Thank goodness I'm not a god.

    As I have said before, the debate really centres around what is a "trailable" boat. In Europe, where I'm from - despite my summer house in Canada - a 2T catamaran isn't considered trailable. Using the data you supply I agree that a 2T empty weight 26/27ft catamaran fits in Category B. But not A. Nearly all boats with cabins are category C. A Hobie cat is Category C

    However a 26ft 2T empty boat with 330sqft sail probably won't have the performance you are seeking, whatever the figures imply.

    Google can't find a link to Richard Atkin's website or any of his designs except on these pages. Can you tell me where some of your designs are sailing, either on the west coast fo the US/Canada or in Europe so that I can compare then to mine. Thank you.

    As I say, in haste
    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
    Last edited: Mar 26, 2008
  7. Richard Atkin
    Joined: Jul 2007
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    Richard Atkin atn_atkin@hotmail.com

    Hi J. My comments were written out of boredom in my own life at the moment. I never intended to insult you or Richard. I meant it in a light-hearted way but I didn't make it obvious enough. I apologise if my comments seemed unfriendly. You are very courteous, and I don't believe you are truely an *** kisser. As you say....it's not always easy to get the true meaning across on the internet, and my dry humour is a bit ambiguous sometimes. Hope we are still friends.
    I would be delighted if you ran my design through your spreadsheet. I can't read the file on this computer. Could you post me some questions?

    Richard, I am not even close to being a naval architect and have no portfolio of designs other than my own incomplete one in this forum. "Trying to design my own cat" in the Multihulls section. You've been there before :) (don't know how to put the link in here, sorry).

    I will continue to follow this thread and try to keep my big mouth shut unless something constructive comes out! :D
     
  8. Kerry Thomas
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    Kerry Thomas Junior Member

    Clamcat

    The hulls do fold under the cuddy. The folding system is unique and developed by myself and the client. It had to fit within 28' and 8'6" max folded width for trailering in the US. As the final design is to be used in Florida it has a bigger rig.
    I have since been asked to design a longer version transportable in a 40' container.
    The design fits within the rules for cruisers built in NZ for offshore including the design loads, openings etc. As anywhere on the NZ coast is likely to get offshore weather. Not stability as no cat is stable to 110 degrees. These rulesare based on offshore racing Catagory 1.
    The 860 cat on the site was designed as a control to see what we lose by having a folding system. She turned out a nice little design in her own right.

    Why i would not recommend either for long offshore passages is the limit on actual load with a 28' catamaran. After you have added essential gear there is not much spare displacement for stores. The added weight of a folding system limits you even more.
     
  9. JCD
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    JCD Follow the Bubbles!

    Hello Richard,

    I also will be brief if my excitement allows me to be.


     
  10. JCD
    Joined: Jul 2006
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    JCD Follow the Bubbles!


    Hello Richard,

    Your apology is accepted. I never considered not being your friend. We're all brothers. I have come to understand one very significant thing with long distance relationships by different cultures. Every dog has a bad day and mis-understandings happen often. In a forum where words can appear imflamed or true humor is not expressed with the pat on the back while laughing out loud, it can be worse. I have become very tolerant in my age and instead of the meltdown, I just point things out and it gets better and we move on.

    The questions for the spread are just common design specifications. Here they are. Get them to me if you have all the information and I'll give you the results.

    Imperial units preferred but units should be consistent whether metric or imperial.

    Length over all
    Beam over all
    Design draft
    Highest point of hull from waterline
    Sail Area
    Displacement
    Length water line
    Beam over all
    Beam of one hull
    Length water line of one hull
    Wetted surface area
    Water plane area
    Combined vertical enter of effort
    Height of Mast from waterline
    Depth of center of lateral area
    Mast clearance at displaced Lwl
    Bridge deck clearance at displaced Lwl


    Hey, don't worry so much about keeping your mouth shut. Feel welcome to contribute more than just constructive things...just mind that the letter does not exactly provide the emotion you're trying to express. Don't read so much into what I said...consider it an observation opposed to a lecture.:)

    Thanks
    J:cool:
     
  11. Richard Woods
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    Richard Woods Woods Designs

    Again in haste:

    I agree it is always hard when writing online to smile or joke. I never really know what the little icons mean

    I don't know what you call empty. I took the approx 2T light from your 1.2 doc file above (like most of the world except the US I am not very good at imperial units, never having done any engineering using them)

    There isn't any wind speed reefing requirement in the ISO standards for deciding design category, so thus no limit to sail area. That is because it can be adjusted by the crew.

    Not to be taken too seriously, but I may not be "god" except when it comes to the ISO standards. As I have said before I have been sitting on the ISO stability committee as the "multihull expert" for over 15 years, (Erik Lerouge joined the committee a year ago). So if I say that you can't have a Category A trailable boat 8m long then you can't.

    Europe has narrow, twisty roads compared to the US. We also have smaller cars. Something to do with the fact that fuel is now about USD10 a gallon in most of Europe. Fuel is SO CHEAP in the US!!! So trailering size has a practical rather than a legal limit
     
  12. JCD
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    JCD Follow the Bubbles!

    Hello Mr. Thomas,

    Please pardon my confusion since I am not familiar with the rules for NZ. I will assume that you mean to say that you have followed the rating organization standards as required by the ISAF OFFSHORE SPECIAL REGULATIONS Extract for Race Category 1 Multi-hulls dated JANUARY 2008 - DECEMBER 2009. These are basically updates of the older versions. Please correct me if that is not accurate.

    I am attaching a link that describes every possible category and everything related to it for your confirmation.
    http://www.sailing.org/1056.php

    The purpose description for category 1 is denoted below. Please note that it is only to establish uniformity throughout for equipment, accommodations and training for vessels racing offshore.
    “1.01.1 It is the purpose of these Special Regulations to establish uniform minimum equipment, accommodation and training standards for mono hull and multi-hull yachts racing offshore. A Proa is excluded from these regulations.”


    The regulations then reinforce the matter by denoting that they do not replace the authority of governing authorities for certification or other ruling agencies as denoted below.
    “1.01.2 These Special Regulations do not replace, but rather supplement, the requirements of governmental authority, the Racing Rules and the rules of Class Associations and Rating Systems. The attention of persons in charge is called to restrictions in the Rules on the location and movement of equipment.”


    Category 1 is defined as follows and I draw your attention to those items underlined which you have pointed out is not your recommendation for the design due to restricted stores capacity.
    2.01.2 Category 1
    “Races of long distance and well offshore, where yachts must be completely self-sufficient for extended periods of time, capable of withstanding heavy storms and prepared to meet serious emergencies without the expectation of outside assistance."



    I have not included the table due to cut/paste issues in the forum page, but it just about covers every possible boat for Category 1. Clearly, the regulation assigns direct responsibility of certification to specific governing organizations as denoted below. I draw your attention to section “a” and “c” which points out that it must meet Cat A requirements for offshore vessels, therefore I will assume the design is not certified to EC or ISO 12215 unless you now say that it is a Cat A certification. If we agree that ClamCat is not rated Cat A, then it cannot be a Cat 1. If you say ClamCat is rated Cat A and Cat 1 then we proceed.
    "3.03 Hull Construction Standards (Scantlings)
    3.03.1 A yacht defined in the table above shall have been designed built, maintained, modified and repaired in accordance with the requirements of either:

    a) the EC Recreational Craft Directive for Category A (having obtained the CE mark), or

    b) the ABS Guide for Building and Classing Offshore Yachts in which case the yacht shall have on board either a certificate of plan approval issued by ABS, or written statements signed by the designer and builder which confirm that they have respectively designed and built the yacht in accordance with the ABS Guide, or

    c) ISO 12215 Category A, with written statements signed by the designer and builder which confirm that they have respectively designed and built the yacht in accordance with the ISO standard,

    d) except that a race organizer or class rules may accept when that described in (a), (b), or (c) above is not available, the signed statement by a naval architect or other person familiar with the standards listed above that the yacht fulfills the requirements of (a), (b), or (c).”



    I have not included the quote from the RCD in an attempt to keep the post manageable, but knowing that you mentioned that you home build, if RCD built by a manufacturer, the certification must be made and if home built for personal use and the vessel is sold within five years, the certification also must be made. It must carry the CE certificate from the EC Recreational Craft Directive denoted above in 3.03.1 a.


    I guess that the best way to get to establish if I am incorrect in assuming that an offshore rated trailerable catamaran exists or not is to just ask you at this point. Does the ClamCat deign carry a Cat A or B rating as defined by either ISO, CEN, ABS, or RCD?

    Please do not perceive this post as interrogative or stand-offish as it is not my intention. If the feat has been accomplished, I would give credit where due and I would do it with great pleasure, but if it hasn’t, then I also would like to be given credit for the research and concept to produce plans for the first “offshore rated Cat B trailerable catamaran by design” and not just as a consequence or chance.


    Thanks
    J:cool:
     
  13. JCD
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    JCD Follow the Bubbles!

    Hello Richard...welcome back hastily...


    Well, empty was a reference you made in a prior post and not understanding, I asked for your definition, but it is now asked of me so I will answer it and in metric also. If the design were 27' Loa (8.23m) and 18' Boa (5.48m), I can get the design into Cat B with her lightest possible displacement, or "empty" displacement of 3808#'s or (1.7T).

    The problem with this is that the general balance of the design as a whole is completely obliterated and her performance and stability suffers with reduced waterline, overcanvassed rig, etc, etc and a redesign would have to happen. In essence she is optimized at 2T +/- a little bit either way.


    In my opinion, this is both good and bad because prudent designers will design a balanced rig and will utilize established "stability boundaries" to produce a maximized offshore capable rig. I have studied these stability formulas long and hard and believe them safe. I have used them in my calculations.

    Then you have the maniac designer that wants his vessel used only when the moon is on the oppossite side of the earth so that his mast does not collide with it during high tide. I believe the rig should be maximized but not overpowered to the point where stability is sacrificed to "potential" speed.

    My calculations are still rough for the design and I will maximize it. I just needed to get a rough idea of where the design would be with different design configurations.

    I won't take you too seriously as you should not me, but be careful when you liken yourself to GOD as he is a selfish GOD and may place his finger on your mast the next time you find yourself in a lightning storm.:D Seriously though, boasting is good.

    I continue to prod and remain hopeful that you will continue to contribute to my thread because I believe that you are without a doubt an authority among many as yourself and I know that you are very knowlegeable and experienced in your profession. So if you say, and I have already agreed because I did calculations of my own, that you can't have a Cat A that is 8m long, then I believe it.

    I also believed it when you said that my design is Cat B according to the design results.:)

    LeRouge's Pulsar 26 is trailerable, but...not offshore rated either!

    I have to get back to reworking the scantlings since I have decided that 27' is the bare "minimalist" length for the concept. I will not make the design any longer than that so it is settled that it will be 27'. I will be updating all the data for the new Loa as soon as I get to it.

    Thanks
    J:cool:
     
  14. Richard Atkin
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    Richard Atkin atn_atkin@hotmail.com

    Hi again, J:cool:
    Thanks for keeping your cool. I wrote your name with your trademark as it is very applicable in this instance, and it should in no way be considered an *** kissing.:D

    Moving on now....
    I tried to fill in all the data, but a couple stumped me. I don't know the combined vertical centre of effort, or depth of centre of lateral area.
    Are you able to fill in the blanks by making a calculated guess...or by working it out from the fbm file?? I don't have a clue, although I can say that the clearance between the deck and sails will be about 6 inches more than is typical for a boat this size. Shouldn't make too much difference.

    ANY information you can give me, regarding my boat, would be very appreciated. (especially if it makes my design look good compared to yours...or Richard Woods :D )

    Thanks J

    Length over all = 28 ft
    Beam over all = 16 ft
    Design draft = 2.9 ft from bottom of rudder or 1 ft from bottom of hull
    Highest point of hull from waterline = 3.5 ft top of cabin or 2.75 ft top of deck
    Sail Area = 380 ft2
    Displacement = 1.604 long tons (3593 pounds)
    Length water line = 27.774 ft
    Beam water line = 14.746 ft
    Beam water line of one hull = 1.74 ft
    Length water line of one hull = 27.774 ft
    Wetted surface area = 150.16 ft2
    Water plane area = 73.783 ft2
    Combined vertical center of effort = not sure
    Height of Mast from waterline = 29.25 ft
    Depth of center of lateral area = not sure
    Mast clearance at displaced Lwl = 2.42 ft
    Bridge deck clearance at displaced Lwl = 1.75 ft
    Beam of one hull = 3 ft
     

    Attached Files:


  15. Richard Woods
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    Richard Woods Woods Designs

    There are already a number of existing trailable offshore catamarans that have been designed as such and then crossed an ocean to prove it. My Skua and the Tiki 30/31 for example are two that come to mind immediately.

    Maybe one of Tennant's trailable cats was also designed for offshore use. I'm sure there are many others.

    To me trailable means you can have it in the water in under an hour with no outside assistance. Transportable means it is still road transport legal, but it will take most of the day to assemble and probably need outside help, eg a crane to raise the mast. I think that for offshore cruising or living on board it is better to go the transportable route. I can't see a situation when you need to rig and launch a live aboard boat in an hour.

    My 25ft Sango is trailable; my 26ft Elf is transportable but has lots more room than a Sango. Even so it is too small to live aboard. My 28ft Gypsy can be built in a transportable version and can certainly be lived on board and can/has crossed oceans.

    I repeat what Kerry says, trailable boats don't have the load carrying for a comfortable fit-out, never mind the stores that most people want for liveaboard cruising. A basic trailable boat can have a solar shower. But a "proper" shower implies pressurised hot water on demand and that adds a lot of weight. Water heater, electric pressure pump, piping, wiring, circuit breaker, shower sump, shower pump out etc. Not only that, but these all mean the shower has to be in a fixed position which results in a lot of wasted space, particularly on an already small boat.

    I consider a Balestrom rig to be the same as an Aerorig. It is easy to arrange daggerboards so they don't interfere with the accommodation. For the last 20 years my larger daggerboarded designs have come with a long, 150mm deep super low aspect ratio beaching keel to protect the hulls when drying out.

    As you know from my website, I have been hit by lightning once so I agree "god" is not on my side.

    best wishes
    Richard Woods of Woods Designs
    www.sailingcatamarans.com
     
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