want to build small sailing tri. need help please

Discussion in 'Multihulls' started by tour, Feb 24, 2013.

  1. tour
    Joined: Feb 2013
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    tour Junior Member

    Hallo there.

    i am new here so first thing is first, an introducting.
    my name is Tour and have a little bit of sailing experience on monohulls. after a backpacking trip to thailand my girlfriend and i had our first real introducting into trimaran sailing. a hobie islander tandem. when i really looked at it, it made sooo much sense. we rented one for 3 days and went island hopping on it.so the bug has now sunk its teeth into me :D

    so after a bit of searching the internet for tris i had come up with following tris that i really like. the cross 18, W 17 and the strike 18 and frank smoot's new 24 foot tri. they are all rather different yet similar to my non informed eyes.

    i would like to use it as a fast,trailable,simple, easy and fun daysailor or weekend camp sailor.not too much to ask really,is it?

    so far i have found lots of hobie 16's available for sale here. i would like to use these as amas and rigging. we have strong winds here and often 1 meter chop (lagoon waves). so must be seaworthy and fairly dry.

    so am thinking of building a +- 18 foot tri with 16 foot amas. also i like the cross 18 seating arrangement, which i can double as a camping style platform for a tent. 2 people berth.we are young so comfort is not essential.

    i would like to use Frank's easy build method as i am not a carpenter but can use my hands. and budget .... still need to save money and would like to build as cheap as possible while still have a strong boat. i will not be building off plans as if it looks right i'll go right.i have enough understanding of sailing and eye for shape.

    so there is sooo much that i need to find out before starting... therefore coming to this awesome site for information and help.so i would like to use this thread to gather the right info on the tri that would suite my needs. i do understand that it might not be the fastest tri out there but i would like to still sail as well as possible.so...the first few questions of many:D

    1 is the hobie 16 a good donor for amas and rigging?
    2 flat bottomed vaka is easy to build but will it handle 1 meter chop and 30 knots of wind without damage. i know a good helmsman will also be a VERY important aspect
    3 i like frank's foam bottomed 24 ft. eaze of shaping.will it hold up to serious chop?
    4 how do you calculate where to add the daggerboard? and what shape? how important is the placing of the dagger?too far forward or too far aft what is the effects?
    5 if i can find a hobie 18 and have the daggerboards in the amas how will it affect the handling?can i then elliminate a vaka daggerboard?
    6 how do you calculate the rocker? want a good pointing, fast and easy tacking tri.
    7 with Frank's foam kevlar hull i could shape a nice fast, wave piercing hull but still can t see a daggerboard in there. dont like the side mounted double leeboards.
    8 with a flat bottomed hull it will be easier to add a dagger but will it really be that seaworthy? 1 meter chop 30 knots wind?
    9 how beamy should it be? like them beamy so what effect has the beam of a tri have.

    so as you all can see this is still very much planning and info seeking time.i would like to start building this year, so any answers good or bad will be greatly appreciated. when i start with this project i will also write up a build thread. hope the questions is not too all over the place.

    thanks in advance
    tour
     
  2. Manfred.pech
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    Manfred.pech Senior Member

  3. Doug Lord
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    Doug Lord Flight Ready

  4. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    The two problems with the Hobie 16 are the unusual beam/hull attachment and the fact that the outriggers have very little buoyancy. However both Dick Newick and Derek Kelsall have done trimarans that used the Hobie as outriggers

    You may also find the fully battened Hobie jib awkward to use on a trimaran and difficult to sheet correctly

    You don't need to use a complete Hobie. You can easily mix and match the parts. So, on our own Strike 18 we have outriggers from one boat, a mast from another, a mainsail from a third and a jib from a fourth. No idea where the rudder came from.

    A Hobie 18 hull may be too big and heavy for an 18ft tri

    I think the solid foam glassed over idea will take a long time to fair up

    Good luck with your project

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  5. teamvmg
    Joined: May 2008
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    teamvmg Senior Member

    Have you ever tried sailing a Hobie 16?
     
  6. tour
    Joined: Feb 2013
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    tour Junior Member

    wow thank you all for such fast replies.

    manfred and doug
    i ve had a look at those sites and boats before, therefore my wanting to build a mix of the boats that i have mentioned. i will now go and try learn more before i take on this endeavour.

    Mr Woods

    i feel honored to be able to chat here with you as your strike 18 was and is my first choice of tri. i love the way she sails and handles in your youtube clips. as we dont really have any tris here where i am i dont have any tri sailing experience. only the hobie islander. which is a different toy. i can see your foam shaping hazards that can arise. my question then how well does a flat bottomed boat like the strike handle rougher water. we can get hectic south eaters coming out of no where and turning things rough real quick. i ask out of no experience from my side. if it handles really well then it ll be the way to go. my experience has been with big mono's and i know how a flat bow can slam therefore my query.
    also how about a hobie 14 for amas and hobie 16 rig? is the hobie 18 a bad idea even if i build a bigger vaka? too heavy all round?
    this is all fresh waters to me so i really am thankfull for all input.

    teamvmg

    no i have not sailed a hobie 16. my sailing experience has been in the charter industry for 7 years, sailing swan 68 and similar shaped bigger monos and also a year on a 140 ft bruce king designed modern classic Alejandra. sailing mostly in the Med and Carribean.

    for me the essence of sailing is on small boats. and these 20 foot and under tris have opened my eyes even more. now to build one :D
    so now to look for a hobie graveyard to get parts.
    regards and thanks
    tour
     
  7. CutOnce

    CutOnce Previous Member

    I've been struggling with a similar set of requirements and have not reached any conclusions. I've looked in as much depth as possible to the alternatives that can be found on the Internet.

    The Internet is a good research tool, but not as good as actually seeing the options in person. Especially important to view in person are home builds and what results can be accomplished in a garage.

    I've built some boats by myself and been involved in other builds by more accomplished and experienced professionals. The quality range I've seen in home builds is vast. Even first class plans of popular premier designs can be badly executed. I've seen a Farrier 31 that wasn't built as well as I did on a home building supply store kid's boat - and I'm no expert.

    If I have anything to contribute to your efforts, I'd say the following:

    1. Guys like Frank Smoot who can produce apparently good looking results without well developed plans are rare. Lack of well tested plans generally result in failing to meet intended expectations. Even though Frank's efforts look great, by my eye the vaka transom drags, the hull shape isn't optimal from a drag perspective and the centreline-only seating really limits performance. His rig choices are skewed to simplicity, not performance. These are not negatives - the boat exceeds his own expectations for his own statement of requirements - but it would not fit mine as well.
    2. Getting the basics right - bulkhead and build stations, panel shapes, scantlings and building sequence will make the build process have a much higher chance of completion than continually adapting mistakes along the way. Scrambling, adaptation and duct-tape style builds are ten times more effort than having a clear plan from the get go.
    3. Building a tri will involve much more effort than building a similar sized monohull. Even if you raid a well stocked Hobie graveyard, adapting aka attachments, engineering to meet required strengths, making sure the result is trailerable and fast to assemble will take lots of head scratching time. I'm personally not certain that adapting elderly cat hulls to be amas is really faster than building purpose designed amas. You are still building/adapting/modding, sanding and fairing three hulls instead of one. Since the goal of a tri is to be light, strong and fast, I've more or less concluded that using production cat hulls isn't the right path. Paul Beiker ended up trashing the Tornado hulls and building new ones for his Trinado. Hobie 16 hulls are under-buoyant and heavy - a big complain from the Tremolino crowd. Hobie 14 hulls are too small. Hobie 18 hulls are too big and heavy.
    4. Richard Wood's Strike 18 with the Quattro 16 hulls as amas seems pretty close. It is a lot of work, and having manned a long board a few times the amount of time to produce a good quality result won't be quick. Aesthetics of the Strike 18 are a personal thing - I'm pretty certain it is a much more beautiful boat to sail than look at from some angles.
    5. I've gone back and forth on centreboard versus daggerboard, one board on the vaka versus dual boards on the amas and even considered the (to me) butt-ugly leeboard option. I like the kick-up option (I live in rocky cold waters), but hate the high drag of gasketed, fussy centreboard slots. Daggerboards (I've built a bunch) are the best option performance-wise, but hitting a limestone reef on Lake Huron at 10 knots plus could really ruin your day. Even with a good crashbox design, repairs could kill a major part of my all-too-short season. Weed pickup and clearing is also a big concern for me. I'm currently wondering about a single leeboard vaka hull and how bad the drag/ventilation penalty is with a surface piercing leeboard versus a well gasketed centerboard slot.
    6. Space is a real issue, as I'd like to have enough room for an "al-fresco" bucket for use on weekend trips. I'm married and don't think my wife would appreciate slave-ship facilities or hull decor. Besides, I'd like to keep my clean freshwater venue ... clean.
    Much of my choices are skewed towards:
    • required minimal build time and effort.
    • real world performance and the potential to fly the vaka. I'd like to see high teens, with the remote goals of over 20 knots if driven hard.
    • real day-sail, driveway stored, fast to rig and de-rig trailer-sailor weekend fun. I live where I've got lots of venue options - St. Lawrence/Thousand Islands, Lake Ontario, Ottawa river, Lake Huron, Lake Erie and Georgian Bay/North Channel.
    • Single handing potential (or realistically two-up with non-sailing wife). My son has reached the age where he's no longer easy to persuade to join into family outings.
    • Balanced choices regarding appearance versus build time and effort. Flat panel ply building is a lot less work than molds, foam core and resin infusion.
     
  8. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    The Strike 18 hull is actually Veed forward, there's a small chine for the first 4ft or so. Even at its widest the hull bottom is only about 18in wide. I chose the simple chine shape knowing its limitations.

    In fact those aren't as bad as it might seem. Wave making is proportional to BWL cubed so a narrower hull is better. And as the chined hull has more displacement than a round bilge one the hull can be narrower for the same weight

    The Strike is designed for those new to boat building so I kept it as simple and flat paneled as possible. The wide wing decks and the windscreen keep the cockpit very dry, important for those who enjoy "going for sails" as opposed to "sailing". My wife likes sailing our Strike or, as she calls it, "going for a snooze cruise"

    The windscreen also means the mast foot is mounted high above heads, yet the same low beach cat gooseneck can be used (remember the Strike is a main hull addition to a beach cat)

    Plenty more about the Strikes, including lots of videos, on my website and youtube video channel

    Final comment, all the boats discussed above are small boats, really only suitable for daylight coastal cruising

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  9. Jetboy
    Joined: Feb 2012
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    Jetboy Senior Member

    I was in a very similar situation.

    I've opted to build a Scarab 18. I think it's a little out of the complexity range you're looking for.

    A local sailor near me has a Cross 18. It looks like a very simple construction and easy to sail little tri. I sailed with it in my Venture 17 and was impressed with overall sailing performance. I did think to myself that it didn't look like it was super comfortable seating wise, nor was it super fast. However, it had a shorter mast and relatively small sail plan. Seating is easy to fix - add some cushioning etc.

    That said, I think there are a lot of great ideas out there for easy to build small trimarans. The strike looks like a quick build.

    I would suggest that you buy plans or develop your own full plans before starting. The money spent on plans is well worth it for the time and frustration you'll save if this is you first boat project. Even thing as simple as having a materials list to work from to estimate costs helps give you a good idea of what you'll need.

    I would not use a hobie 16 as a base boat. Amas are not ideal for this. The best boats for amas will be those with daggerboards and symmetrical high volume hulls.
     
  10. CutOnce

    CutOnce Previous Member

    Richard:

    I really like the Strike 18 and have carefully evaluated the thoughtful compromises made to arrive at the design as executed.

    I know it is almost impossible to make perfect choices on build simplicity, intended users skill levels and real performance. Especially if you are hoping to design one boat that many people will want to build. Every boat is a collection of compromises.

    I've pored over your website, videos and all client build reports to distraction.

    Has anyone completed a Strike 15 yet? I'd love to hear how the boat performs on the water - and see how it has turned out. The Strike 15 is a lot closer to many of my preferences, although a little small. I know you've completed the basic vaka construction (in the video), but has it been wet yet?

    --
    CutOnce
     
  11. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    Glad you like the Strike 15. I've sold about a dozen sets of plans. The main hull of my own Strike was finished last summer in Canada and was then stored as we are not in Canada during the winter. Work on the crossbeams and outriggers will recommence in April. I have the rig, rudder and daggerboard all ready to fit

    The complete main hull weighed 56kgs, the outrigger mockup about 10kgs without the deck. So it looks like it's coming in at about the right weight

    The Strike 15 is a very different concept boat to the Strike 16 and 18. Much more racy (I know my wife won't sail it - see my previous post)

    I hope that helps

    Richard Woods of Woods Designs

    www.sailingcatamarans.com
     
  12. Stumble
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    Stumble Senior Member

    Richard,

    Do you have a projection yet of how many hours a Strike 15 will take to complete? I am considering building a small tri like yours, but don't have the time to dedicate to a long build.
     
  13. Richard Woods
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    Richard Woods Woods Designs

    Building times are always hard to predict as everyone works at a different speed. Also I don't include finishing/painting time as that is another huge variable

    But IIRC the main hull took 97 hours to finish. So probably 150? for the whole boat ready to paint

    I'll know for sure by the summer. Whatever the time it will be worth it!

    Richard Woods
     
  14. Stumble
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    Stumble Senior Member

    That sounds pretty reasonable. I just didn't want to get into a 3-400 hour build.
     

  15. Richard Woods
    Joined: Jun 2006
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    Richard Woods Woods Designs

    No I wouldn't want a small daysailer to take that long either, but it could do if I had designed the boat differently

    Richard Woods
     
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