Weta: Normal and Turbo Proposal

Discussion in 'Multihulls' started by Doug Lord, Jan 11, 2011.

  1. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 342, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    This is an update of a post from an earlier thread sparked by the fantastic picture below.
    This is one great boat- as I've been able to see first hand lately.It has a planing main hull so is not speed limited in the same way some of the smaller displacement trimarans are. It will not fly the main hull but is nevertheless a fast boat-see the video of the Pacific Coast Championship.
    What I'll do in this post is figure out some of the design ratios of this boat and then see exactly what it would take to fly the main hull with one or two crew. A Turbo Weta will be described and and detailed.
    --
    Weta Specs(most supplied by Weta Canada):

    Length - 14 Feet 5 Inches (4.4 m)
    Beam - Rigged 12 feet 2 inches (3.7 m)
    Beam - De-rigged 4 feet 11 inches (1.5 m)
    Main hull-beam at waterline- 2.71'
    Main Hull L/B at wl- 5.3/1 (planing hull)
    Ama length -11'(est)
    Ama beam - .625'(7.5")
    Ama L/B -17.6/1
    Sail Area - Main 8.3 sqm (89 Sq Ft)
    Sail Area - Jib 3.2 sqm (34 Sq Ft)
    Sail Area - Gennaker 8 sqm (86 Sq Ft)
    Total Sail Area- 209 sq.ft.
    Weight - Main Hull 123 lbs (56 kg)
    Weight - Float with Beam Frame 37 lbs (17 kg)
    Weight - Mast 9 lbs (4 kg)
    Weight - Rigged Total 220 lbs (100 kg)
    Mast - Length 21 feet 4 inches (5.6 m)
    Mast - Height above Water 24 feet (7.3m)??
    ---------
    Design Ratios-"normal" boat:
    Normal boat is defined as boat with one 175lb crew

    --SA/D=36.6/1
    --SA/WS=2.66/1(optimum immersion of ama for lowest wetted surface and max RM)
    --W/SA= 3.29
    --SCP/Total weight= 73%( Note since the normal Weta has a planing main hull this ratio is particularly interesting since boats with a ratio above 30% should be able to plane upwind)
    ----------------
    --Max RM-based on company reported capacity of 440lb and max buoyancy of ama-340lb.-(not a normal sailing configuration but one that must be used to engineer the boat or there could be product liability problems)-4815 ft.lb.
    --Max "normal RM" -with one 175lb crew in hiking position and lowest wetted surface of ama for the best RM= 3048 ft. lb.
    ====================================================
    ====================================================
    TURBO WETA

    -----
    Changes to the specs are listed below: (Note: there is talk among some Weta dealers of a Turbo version of this boat. Also the possibility of a completely new boat. This is the result of my exploration of the possibilities in "turboing" a "normal" Weta with the least changes possible-enjoy!)
    --
    Upwind Sail Area: 200 sq.ft
    VERY IMPORTANT: This sail area will require a new max capacity of 350lb so as to not overload the EXISTING structure. Weight increases will be very limited(main foil, rudder foil, ama foil , larger mast). Estimate for total additional weight: 9lb (3 hydrofoils), 7lb mast, 6lb sail for a total of 22lb.
    It is imperative that crew position when sailing at max capacity(350lb) is limited to 8' from the CB of the ama. If a foolproof way of doing this can't be devised ,max capacity for the Turbo will have to be lowered further. This is important so as to keep the boat within the structural boundaries of the design.
    The Turbo, with 200 sq.ft. SA(same as an International 14) can be sailed singlehanded in the same breeze as an F18 cat. Or it can be sailed with two 175lb crew . It will fly the main hull in as little as 6-7 knots breeze.
    --The boat uses a foil that pulls down at some times similar to the windward foil of a Rave hydrofoil(or any other foiler that uses a foil or foils to generate RM). As shown(and detailed) in the specifications post the maximum pressure this boat can sail in is 2lb per sq.ft.-11% higher than an F 18 cat. Like the Rave at a certain point sail area will have to be reduced to avoid structural damage. The Rave posted a warning in the cockpit to remind the "pilot" of this. This boat-if ever built- will be tested to find the exact apparent wind speed or boat speed that reefing should take place-but I can say it will be somewhere over 25 knots. This is a minor drawback to major
    advantages provided by foil assist:
    1) early takeoff of the main hull
    2) the ability to sail at maximum RM(righting moment) regardless of crew weight in the range of 140-350lb.,
    3) the automatic control via the wand of the boats heel angle when flying the main hull.,
    4) Drastically increased pitch resistance compared to a similar design w/o the foil.

    --The beauty of the choices described here is that the boat does not have to be changed structurally at all!( may require strengthening here and there-Roger Kitchen would decide that) Even in the worst case scenario the max RM barely approaches the designed maximum RM. The same limitations in very strong wind-over 25 knots-will have to be tested and considered as with any boat that can use a hydrofoil for righting moment. The max speed of the boat will increase dramatically especially in light to moderate wind.
    The modifications will include a new mast, new boom new sail, new daggerboard /foil combo and the installation of the retractable ama foil. There is a distinct possibility that after more research and testing that the Turbo version and original version could be interchangeable-keeping costs down. With the proviso, of course, that the max capacity of the Turbo version is limited to 350lb(see above) rather than the 440 of the "normal" version.
    ---
    Turbo Design Ratios-only the ones that changed:
    --
    SA/WS=20/1-dramatic change
    W/SA= 1.975(single crew)
    = 2.85 (double crew-same as Moth with Gulari)
    TURBO max capacity limited to 350lb( or less)!
    Max RM ,single= 3365 ft.lb.
    ------------------------
    from Gino Morrelli(famed multihull designer with Morelli and Melvin):

    "Foils are definitely the way to go: it's an instant turbo".

    ------------------------

    Weta West Coast Championships- Great video of the main hull planing: http://www.youtube.com/watch?v=LKpiVZvu-a8&feature=player_embedded
    ------------
    spectacular pix of Weta sailing:

    (click on image)
     

    Attached Files:

  2. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 342, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Weta

    Interview with Roger and Chris Kitchen about the Weta:

    This is the second part of a story I posted on November 11 about a cool trimaran that's making waves on San Francisco Bay, and becoming popular among Marin sailors among others. While in New Zealand over the past few weeks I got to spend some time with the creators of the Weta trimaran, Roger and Chris Kitchen. We met at their house in Campbell's Bay on Auckland's North Shore, where much of the initial work on the Weta was performed.
    * How did the Weta come to be?

    Roger Kitchen: When I started sailing with the kids I was always looking for a family boat that I could sail on the weekends and be able to take the kids out and teach them to sail. But I didn't want a two-handed boat so it had to be a single-hander. There wasn't anything about really. When I went to the Youth Worlds with Chris who raced a Hobie 16 in France in 2001I saw the big kids teaching the little kids how to sail in multi hulls and it looked seriously interesting. That sparked a multi hull interest in me and I kept thinking about it. At the time I was in committees for Yachting New Zealand and I felt it would be a brilliant training boat concept for kids both for learning to sail and as a single-hander with heaps of performance.

    * Who designed the Weta?

    Roger Kitchen: We put all the ideas on the table, got all the dimensions we wanted, then got someone to draw up some lines for us. Then we spent three years developing the boat (LOL). It got a really good response so we decided to put it into production. At that stage I was still working full-time and Chris was still at university doing his engineering degree. We started manufacturing in New Zealand, which just about crippled us as we're not really a manufacturing nation. It was really expensive and quite depressing. So, I shipped all the molds to China thinking it'd either work or I that at least I wouldn't have to look at them and get more depressed! We followed the molds over there - Chris had finished his degree - we had planned on originally being there for one month but it ended up being more like ten. The second factory we found worked out and we've been there almost five years now.

    Chris Kitchen: We contracted a local multi hull designer* to draw the lines for us and we built it here at home, and developed it from that. The initial concept we had was just a trimaran with a mainsail only - a learn-to-sail thing - but as soon as we started building it we started adding sail and changing it. At that point there was no intention to go into production. It was just a little project but it was the interest that came from the boat being at the beach and being seen by other people that spurred things on. It would be interesting to bring out the initial drawings because it's become quite a different boat (LOL).

    * How have you been marketing the boat?

    Roger Kitchen: Things really opened up for us and it's really expanded bit by bit, starting off with people we knew overseas who were interested. We have about 25 countries on board. We've never sought out dealers, they've been people who have contacted us which is the best way. Dave Berntsen (San Francisco, Calif.) is a typical example - fortunately multi hull people see the boat and they can't leave it. We've just hit about 520 manufactured boats - currently we're really busy because we've just opened up our booking for the European spring. We're really happy with the way its going and it seems to have hit the spot for both families and then racers. A lot of Chris' friends who are Olympic sailors have helped in the development of it so it's a good performance. As it wasn't designed as a racer, we are thrilled that guys will borrow a boat and go out in a bit of a breeze and have a hell of a good time. It's taken a long time but we're happy it's has as we seem to have it right. It's a boat that seems to have that niche - there's nothing like it really that fits the position.

    A lot of the dealers are completely passionate about the boat and we are totally committed to giving the best possible quality - we have to spend a lot of time up in China where you can get good quality product but you have to keep tight control and spend the time. We have a great group of dealers. We have met some fantastic people along the way - we have just got new dealers in Austria and Germany. We get people who want a change of lifestyle, kind of like me who put all my retirement into this and thought, well, I'll go down fighting - passionate sailors and love the product. Or some, like the Austrian, just saw a video of the boat, liked the concept, and bang, ordered 10 boats. Our dealer on the east coast of the US has just ordered 60 boats - a massive commitment. It's all about the concept - the ride, the people, the lifestyle - healthy, fitness, family oriented. Our sales have kept on going.

    * (To Chris) What was your input in the project?

    Chris Kitchen: I developed the Weta with Dad - we came up with the concept, I was there for the testing and building - during my summer breaks at uni I was coaching and sailing as well as working on the Weta. I finished my degree, we went to China and its been non-stop since then.

    * Have you done anything different to the boat since it's inception?

    Roger Kitchen: We resisted the whole time to go for another meter on the mast, a bigger this or that, because it had to be an easy one person launch-retrieve family boat. After now building all of these boats I don't think we want to add another half meter to the mast or make it a bit wider - we're quite happy because it fits the brief. We've been quite restrained.

    Chris Kitchen: We've had quite a few owners who have thought they needed a bigger main so they've put one on and made other modifications but they find after a few months its too much in the breeze so they take it back to the original boat. One of the criteria was that it had to have a decent performance. There are too many boats out there that perform like dogs and we couldn't do that. We were willing to trade off performance for the ease of use.

    Roger Kitchen: We weren't competing with a Hobie 16 with two guys and a wire and lots of wind. But on the other hand, if you wanted to go sailing with one person, we'd eat them. You go to the beach, put the mast up weighing 6 kilos and it's easy - you don't need two people - it's a one person thing. But it does perform - it goes to windward beautifully, its nicely balanced and it's a real pleasure to sail. We wouldn't want to change anything at the moment.

    * Where may you take this boat in the future? Anything different?

    Roger Kitchen: (LOL) I'm trying not to look across at the neighbor's garage... this boat is a one design so the only refinements are in the manufacture, no dimensional changes, changes of fabric - last Nationals in New Zealand boat number 11 won so it's not the latest boats that are the quickest boats or anything like that but we have got another boat underway.

    Chris Kitchen: The main focus is to grow the Weta and get big fleets racing around the world yet it's not just about racing - you get the balance and the mix - there's quite a lot of classes that are exclusive for families. With the Weta there's full involvement but at the same time you can get some top-level racing. But we do have a little project on the back burner but it's probably some time away.

    * How's your price point in the market?

    Roger Kitchen: We've tried really hard to keep the price down - as you can see, we're all working out of a really little space here - some days we've had 16 boats on the back yard. Everyone is making a real effort to keep the price down. We think they get a lot of product for their dollar - quality equipment. It's not a lot more than a Laser. We've never had any reaction that the boat is over-priced. It's just launching in the past three years has not been an easy time.



    * What did you guys do pre-Weta?

    Roger Kitchen: I taught mathematics at high schools and university. After 25 years of doing that, I'd always had this thing about doing a boat in mind and Chris's passion for sailing was the catalyst to do it. We've had a huge amount of fun. I come from a very recreational sailing background but had been involved with a lot of administration of yachting and racing.



    Chris Kitchen: I've been sailing since I remembered. We started off cruising and recreational sailing but got a sniff of racing at the Torbay Yacht Club when I was about 7 and that was the end of it!



    *Why do you think the fleet in San Francisco is so big?



    Chris Kitchen: The Bay is so perfectly suited for it. The boat likes 15-25 knots. Dave's done a lot of good work there plus I also think the lifestyle there fits well. All the yacht clubs there have been really good in involving the class and the structure is all in place so its perfect.



    *With the next Cup likely being in San Francisco on a multihull, can you see yourselves becoming really busy?



    Roger Kitchen: Yeah, it's exciting - the timing has been great for us. We received a photo from someone in the States who have already sign written their trimaran as an Oracle, like a mini Oracle, and named it Pupzilla or something. Seriously, we can see huge opportunity but the main thing is if it means the average Joe Public can identify with a 4½ meter trimaran, it's good. The boats are very stable and forgiving and give people a real sense of speed and excitement. If you can spark off any interest in kids its brilliant.



    Chris Kitchen: Keeping up with the manufacturing side of things is a challenge - you can't grow massively over night, it takes time to plan these things and keep quality as you increase production.



    * Where did the name come from?



    Chris Kitchen: We wanted to keep it a unique kiwi product (LOL). As soon as we stumbled across we knew it was the right thing. You'll find out when you sail the boat that there's a bit of play on words...it's an iconic insect that looks a bit like the boat and it just seemed to fit. We knew if it were to succeed it would only do so through export - New Zealand is quite a small place - we have about 50 boats here. Sometimes we have to give some pronunciation lessons.

    * Rumor has it you are transitioning from bright colors to a white hull?

    Roger Kitchen: We were for manufacturing reasons but the strong reaction has been to stick with color - yellow and red. Colors can be quite difficult - gray boats are easier to paint and touch up. Part of the appeal of the Weta is the brightness. Because we're quite small we can make whatever really and we have it sorted now. Color is quite a personal thing although it does create difficulty for the dealers. It was a worthwhile exercise but it's all resolved and we'll keep manufacturing colors.

    * How did you choose to work with Gaastra (on sails)?

    Roger Kitchen: We had a tough time with our first manufacture and were looking for a new one. I was also looking for sail makers and met Ronny Tang from Gaastra - he saw the concept and totally believed in the boat and did anything he could to help me. He found our current business partner in China who he knew of for us. They'd been manufacturing Chinese fishing boats for many years and more recently manufactured Current Design, the American kayak. So they'd already done vacuum technology and such. So there's been a nice strong connection there.

    * Chris, did you think you were going to graduate from University and do this?

    Chris: Well, I was going to go sailing actually - that was my real passion. I went to university to get something behind me before I went off sailing, but this all happened along the way. I've found a good balance and racing at the moment. With the job I travel quite a lot so can attend regattas many places. I'm currently racing on 18 -foot skiffs which is what I enjoy.

    -- For more on the Weta visit www.wetamarine.com

    Roger & Chris Kitchen at their Auckland, New Zealand home, Nov 2010

    * The Craig Loomes Design Group .
     
  3. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 342, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

  4. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 342, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

  5. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 342, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Weta

    Picture from "Dinghy Anarchy"-Weta in the Gorge-boat had mount for a video camera and there should be video at some point.

    click on image:
     

    Attached Files:

  6. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 342, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

  7. cavalier mk2
    Joined: Mar 2010
    Posts: 2,123
    Likes: 55, Points: 48, Legacy Rep: 214
    Location: Pacific NW North America

    cavalier mk2 Senior Member

    Wetter Weta ? Very fast, it would be fun to compare a wing deck version....Would the wing bottoming on the taller waves be faster by not allowing the hulls, cross arms, topsides crew etc...to drag through the water ? It wouldn't sink so much and would be drier....
     
  8. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 342, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    =========
    It's a really wet boat-almost any video shows the crew getting hit by a firehose. My solution is to lift the main hull out of the water..... Probably be a lot faster ,too.
     
  9. cavalier mk2
    Joined: Mar 2010
    Posts: 2,123
    Likes: 55, Points: 48, Legacy Rep: 214
    Location: Pacific NW North America

    cavalier mk2 Senior Member

    But more expensive...
     
  10. Doug Lord
    Joined: May 2009
    Posts: 16,679
    Likes: 342, Points: 93, Legacy Rep: 1362
    Location: Cocoa, Florida

    Doug Lord Flight Ready

    Weta

    Any way you correct the firehouse is going to cost something.....You can live with it for the next 15 years or fix it now....At least, I want my tri to be fast and dry where I'm sitting.
     

  11. cavalier mk2
    Joined: Mar 2010
    Posts: 2,123
    Likes: 55, Points: 48, Legacy Rep: 214
    Location: Pacific NW North America

    cavalier mk2 Senior Member

    I agree, fast and dry pants are vastly underrated in the sport boat market. I like the Weta, they look like a baby Nicol Clipper in the hulls which made me think of the wing approach. In that size range roto molded fairings could be an option. I thing the wing bouncing along would save drag over the fire hose hitting the less streamlined deck and crew.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.