New Take on Tremolino

Discussion in 'Multihulls' started by Chris Ostlind, Apr 27, 2007.

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  1. Chris Ostlind

    Chris Ostlind Previous Member

    I have just finished a new design study for a boat that has many of the flavorings of the Dick Newick designed Tremolino, the French Tricat and the folding mechanisms of many of the boats from multihull design guru, John Marples.

    The new boat is called the Laguna 20 and it makes use of some of those miscellaneous beach cats you probably have along side of your garage on trailers. Imagine your previous, hotshoe beach cat, transformed into a high performance trimaran with enhanced stability and a seriously reduced tendency to capsize?

    The Laguna 20 design, as pictured, uses the hulls from a Nacra 5.2 beach cat for the amas, along with the trailer and the sailing hardware, maximizing your previous investment in a sailing cat. This turns your long lost beach cat into a fast trimaran with greater stability, while being just as easy to rig on the launch ramp.

    The Laguna 20 is 20' (6 meters) LOA with an unfolded beam of 5.1 meters. Sail area is 20.4 - 23.2 sq meters, depending on selected rig, as it can handle the standard Nacra 5.2 rig all the way up to Hobie20 rig area.

    This boat is a home buildable, marine ply S&G main (vaka) hull, with cedar stripped cabin structures and fabricated aluminum struts for the folding process, allowing easy transport and storage.

    The design study, as pictured, addresses this process with the hulls from a Nacra 5.2 meter cat, as that model has very nicely formed hulls with sufficient forward buoyancy to meet the needs of the slightly heavier and potentially faster trimaran. The hulls of the 5.2 Nacra are also very light in weight compared to those of other, comparable beach cats.

    I have purposely left out the trampoline surfaces from the main hull out to the amas, to allow you to fully visualize the folding strut system.

    I'd love to hear your comments, as well as constructive criticisms.

    Chris Ostlind
     

    Attached Files:

  2. catsketcher
    Joined: Mar 2006
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    catsketcher Senior Member

    Chines

    Hello Chris

    I like your design. I just kayaked past a similar style boat this morning. It was built from 2 trailertri 18 floats and a new main hull. It is pretty fast.

    I gather she is built from ply or other sheet material and this gives you the chines. My take on this is that a multichine hull may be more work than a strip foam one. It depends on the material and how fair you want the chines. Such a gently curved main hull would be very easy to build in vertical strip foam. I like this method and used it on my little folding cat.

    How does she fold? I can't see any of the secondary struts Farrier uses. Does she fold this way or is it more like the Marples 26 that has only one set of struts.

    BTW - I remembered you when I had to send some DXF files away the other day. You helped me out about a year ago so these files should be good straight out of the box.

    cheers

    Phil Thompson
     
  3. waikikin
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    waikikin Senior Member

    Chris, looks nice, I've heard a lot of wispers/rumour/fact & fiction on similar sized "sport" tris for one design/mixed fleet racing from a few different desgners, seems like an opportunity for some sweet competion on the race course & in the market place, how exciting would it be to see & race fleets of this style of boat sailing on the edge :cool: Do the floats remain original especially in the beam mounts? There looks to be a lot of hull overhang? forward of the front beam & I imagine that would give the mounts & beams quite a workout given the increased weight of the tri main hull & beams. The donor boat seems like a good way to cut the cost & hopfully make a more attractive entry into ownership. All the best with it, looks great:) From Jeff
     
  4. Doug Lord

    Doug Lord Guest

    Tri

    Very good looking idea ,Chris. Depending on how much ease of sailing plays a role in your conception of this boat you might give some consideration to getting rid of the daggerboards in each "ama". Maybe just use one in the main hull or even a retractable centerboard.
     
  5. Zoro
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    Zoro Size doesn't count!

    Whatever happened to the Zona 65?
     
  6. mattotoole
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    mattotoole Senior Member

    To me it makes a lot of sense to use the boards you already have. Not building a new board and case for the main hull would save a lot of time and money.

    I'm intrigued by this kind of boat too. Looks great!
     
  7. rapscallion
    Joined: Oct 2006
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    rapscallion Senior Member

    I like it!!!

    have you figured out how much it would cost to build?

    did you calculate the bruce or the MR numbers? How much would it weigh?
     
  8. Chris Ostlind

    Chris Ostlind Previous Member

    Nice

    Thanks so much for the kind comments guys. I'll answer your posts in turn.

    Phil:
    Yes, the original design was done for a plywood build. Many reasons for that design choice, but I'd like to thank you for the suggestion to look at a foam core possibility. I redid the vaka hull to reflect a foam core build in female forms and like the way it looks.

    The Laguna folds simply, much like the Marples system with a single strut unit at each aka. I was looking to keep weights low, as well as create a simplified fabrication process. The amas weigh-in at less than 90 pounds right off the beach cat, so they can be handled simply by a solo. The vaka ends of the tubes slip into molded sockets along the lines of the Seacart tri and then the struts are clamped down to keep the whole thing in a triangulated truss.

    Jeff:
    There are considerations at the mounting points, as you point out and I'm confident that I have solved the issues for reasonable use.

    As for seeing a bunch of these boats jamming around a course in close quarters, well... we'll see how that goes. I was thinking more along the lines of a suitable recreational boat that allowed former beach cat flamers a chance to make use of their semi-retired boats, now that they are somewhat older themselves.

    Doug:
    Your suggestion is well taken. There's an option for each builder to make use of the standard daggerboards in the amas or build a trunk and centerboard as they see their best use. If a few of these plan sets go out, I'm sure I'll see both options being explored.

    Zoro:
    The Zona 65 hasn't died. It just got pushed back on the to-do list in favor of a lighter, more easily built boat that can give immediate return on time invested. Since the folding system on both boats is pretty much the same style, I have generated quite a bit of data to go forward with the Z65 in the very near future.

    Matt:
    Yes, using the daggerboards probably does appeal to enthusiasts a bit more than does a centerboard. Guys with performance potential in mind typically do go for the simplicity of the daggerboard setup, where camp cruise/beach picnic guys like the centerboard solution.

    As mentioned, it could go either way, so a solution is at hand for both camps.

    Raps:

    I'm thinking it would cost $4.5K to build the main hull in foam, get it rigged and fabricate the struts. Figure another $1200 to $2200 to nab a nice donor boat and probably a couple of hundred to tweak the trailer to accept the trimaran, rather than the cat and you have it. There will always be miscellaneous expenses such as painting, anodizing, replacement of sub-par hardware, etc. so you should plan on a slush fund.

    Really clever builders who know their way around eBay or Catsailor's used gear listings could come up with more for less.

    The Bruce Number for the Laguna is 1.46, so I expect the boat to perform nicely when compared to many beach cats.

    Thanks to everyone who took the time to write with their thoughts. I'll be taking another long look at the design to iron-out all the little stuff and try to start building the first example by the end of the summer, other build commissions depending.

    I've included a rendering of the foam cored, smooth hulled version of the boat, not that it varies too much from a quick glance. I expect it will be slightly more efficient and a decent amount lighter, contributing to better performance overall.

    Chris Ostlind
     

    Attached Files:

  9. rapscallion
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    rapscallion Senior Member

    NICE!!!!

    Alot of bang for the buck when compared to farrier, corsair and the scarab.
    I'll calc the bruce number of the L7, and see how your design compares to that.. I'm thinking it will look good. Out of all of your designs... I like this one the most!! Please keep me updated on the progress.
     
  10. Zoro
    Joined: Jan 2006
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    Zoro Size doesn't count!

    Survey of One

    First up apologies for posting here but the original thread is closed (too old!) and it is kinda related to Chris's new design.

    Zona 65 Thread

    Chris,

    Seeing that you are still working on the Zona I have two suggestions from my perspective as a potential buyer of such a design. They are simple enough and nothing that muck with the designs integrity (I think, but then I am no designer). They are probably something that a builder could do but from my perspective it would be nice to see these small things in the design from the git go.

    1. I don't know if you are familiar with the companion board arrangement on the Farr 6000 T/S. Its a 3 board system, two boards port and starboard and then a traditional companionway board. I think it is great and would work well on a boat like the Zona making the limited internal space much more accessible and usable.

    Farr 6000 Picture

    2. Open walk in transom. I think this is a very desirable feature especially for a craft that is easily beached.

    Best of luck with it, I will be interested to see the final product. I'm busily refurbing an old Seawind 24 at the moment, shes not ideal but a heck of a lot of fun for the $$$$.

    Cheers
    Z
     
  11. Zoro
    Joined: Jan 2006
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    Zoro Size doesn't count!

    PS The new boat looks like fun, a good option if you are getting a bit past it for your cat or have added kids and don't want to flog the old NACRA. Gotta be a market for it, no?
     
  12. waikikin
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    waikikin Senior Member

    Zoro, "survey of one" is fantastic, I'm gunna steal it & use it myself, I also have a bashed up seawind- very slowly keeping ahead of time, hope to put it in the shed for a refurb when time permits. Regards from Jeff:)
     
  13. Zoro
    Joined: Jan 2006
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    Zoro Size doesn't count!

    Obviously a man of impeccable taste :D

    Why are they yelling "off topic" ? Yeah, yeah OK... sheesh! LOL :)

    Back to things with 3 hulls...
     
  14. rapscallion
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    rapscallion Senior Member

    How much lighter do you believe the boat will be if it is constructed out of foam vs. ply?

    Do you think this hull shape would lend itself to the cylinder mold construction
    method?
     

  15. Chris Ostlind

    Chris Ostlind Previous Member

    Weight comparisons

    The foam version would save approximately 75-90 pounds, Raps. This isn't a very big boat at 20' LOA, so the total weight savings are limited to the surface area of the hull, deck and bulkheads. If going fast is your objective, then the foam cored hull with the H20 (comparable) rig is the way to go.

    As for cylinder molding... I have no idea. I've never built in that style and have no basis for making the determination. Just looking at some of the examples on the Web would lead me to beieve that it could be done in that fashion.

    Chris
     
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