Multihull designer Bernd Kohler contacted me last week and let me know about his newest design – “Little Tri.” Bernd initially designed and built this boat as a daysailer for he and his wife. (He explains in the story below). But then many people started asking him if he could make plans available so they could build this boat too.
It appears to be a fast, light boat. And may be of particular interest to anyone who’d like to build a small tri on a budget.
As you’ll see here, there’s nothing “fancy shmancy” about this boat. It utilizes a used “Sunfish” sail, for example. And yet, the sailing comfort and performance of this boat seems quite remarkable.
I hope you enjoy seeing Bernd’s “Little Tri” as much as I did. Plans for it are available both at Duckworks and Bernd’s own website.
Update (10/30/14): You can click here to download an article Bernd has written detailing the construction of Little Tri.
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Little Tri
by Bernd Kohler
Being boat-less for some years, the time was ripe for a new boat. Besides other considerations, I would
prove to myself that I can built a multihull in 100 hours for €1000,00 as I have done 1979.
Little Tri
Then there where different monohulls, from small dinghy’s to cruisers. My last new experience was sailing a kite buggy (not built by myself) some weeks ago.
In 1979 I started with catamarans. And now a trimaran or better, a double outrigger boat.
This for various reasons. One of them, after a stroke my wife is paralyzed on one side. She would like to sail again too. So it had to be a boat where one can sit in. The logical choice was a trimaran.
Sketching around a bit, LITTLE TRI emerged. From the beginning, I intentioned to build it quickly and for low cost. For example, PVC irrigation tubes where planned for the amas. .
The result is more along the lines of the double outrigger boats which are common in some parts of the
Pacific. So hiking out would be necessary. No problem. The trampoline/seats are a perfect place to do so.
To connect the akas to the hull and amas, robes are used as on Pacific outriggers. Only to connect the akas to the hull I now use stainless steel clasps. (Is a lot faster than attaching the akas with ropes.)
The hull is a high aspect ratio sharpy hull. With its slap sides easy and fast to build. Construction is with
Plywood / glass / epoxy composite, as all my designs.
The rig base consists of a Sunfish sail on a windsurfer mast. The beams are made with aluminum tubes.
For good windward performance, I chose for a dagger / leeboard. The daggerboard rudder is in a cassette.
I managed to build the hull in 73 hours. But then it started. The irrigation tubes I could get where only 3 m
long. But the amas have to be 4 m long. There was extra work gluing and glassing them together.
The delivery of the Aluminum tubes was 3 mounts too late. They where also wrong size; instead of a wall thickness of 2,5 mm, they were 5 mm. So by the end, it took 110 hours to build the boat and the total end cost was €1139 – Euro. With good tubes initially, the cost would have been €1019 Euro.
Did I meet my goal? I would say, “Yes.”
Here is a short “walk around” video of the boat…
Because of the late delivery time there was sailing time lost and it would have been done under better circumstances. I am very satisfied, however, with the performance and handling of the boat.
The first two sails where in light wind. Here is video taken during one of them…
The last sail was under better conditions. Strong offshore wind with a flat sea. The maximum speed I could observe was around 13 knots. More important for me though was that this boat has a very good handling quality.
Coming about is a tootle. The boat sails surprisingly dry too … so no test yet for the self-training cockpit.
Here the main particulars of the boat:
Length: 4.70 m
Length ama: 4.00 m
Beam: 3.80 m
Weight: 75 kg
Positive floatation: 275 kg*
Sail area till: 13 m2
* Hull only, under foredeck and cockpit floor, without aft compartment
At last, a cockpit that is self-draining and 2 m long. It measures a maximum 0,57m and minimum 0,5 m in size. With a tent cover, one would have a snug yet nice place to sleep.
The boat would make a nice little trekking boat for one person. For dry storage, the mast compartment and aft compartment can be used.
This boat was meant as a personal project. But many people where asking me to make plans available. In the end I did.
If anyone is interested in buying a plan they can visit either my web page or Duckworks
— Bernd Kohler
Update 11/12/14 – Short video about the building process for Little Tri…
Very nice looking boat. Most small DIY tris seem to use a leeboard on a pivot, but I noticed you use a daggerboard that seems to slide into an external trunk. I like its simplicity. Can you comment on this aspect of the design? Robert
Hello!
Wellcome the excellent designer Bernd Kohler… I love his approaches…
Love his modern gaff concept ( not here but he could post some on it)
love the rudder here, the self bailing cockpit, the rough but very effective trampolines idea (already stolen Bernd !), the positive floatation
I am less convinced of the one (one is it ?) position of the leeboard. I’d rather have two…
and epoxyed attachment of amas… I think they would be better served by through-hull mechanical fatenings such as threaded rod.
One last thing… I ‘ve been in touch with Bernd to buy the gaff plans, but found it difficult…
Is it any easier ? anything that can be bought with a credit card ?
Thanks in advance and cheers for little tri !
Hi Stefano,
Check out how Gary Dierking attached the PVC amas to his outrigger sailing canoe here – http://outriggersailingcanoes.blogspot.com/2008/04/pvc-amas.html
I like his approach a little better.
Can’t comment on the buying process at Bernd’s website. But I do know that Chuck (at Duckworks) is a great resource for the full plans, should someone want them. The customer support at Duckworks is always great.
Hi there, I normally do not comment to blogs on my designs. But there are exceptions of the rule.
In a high aspect ratio hull one dagger board, even a lee/luv board that it is, is normal. On each side one would not improve sailing performance. The sliding board can be trimmed also back and forward to alter the CP. I could trim the board so that the boat holds its course. The mounting pieces on the ama/aka connection is the lightest possible solution. Important is to have a layer of glass cloth where the pieces are glued to the amas.
To order Little Tri plans click on the words and you on the order page which leads direct to Paypal.
Hello Bernd,
just bought the plans and they are very neat and cheap for the boat this is. I also appreciated the “almost NACA” rudder and daggerboard construction and the capability to trim it in the case. I just hope the case construction is strong enough when the board is not on the lee side but will be pulling away from the hull.
All in all I recommend these palns and boat to all that want a car-toppable capable small trimaran. Bernd has als oa very interesting verison of gunter rig and wishbone gaff, check on his site…
Cheers to Bernd ! , Stefano
Just purchased the little tri plans and can hardly wait to get a start. Not sure I like the leeboard box on the side, looks weak to me and may hit the sail. but will follow the plans before trying to modify anything. I live in south , Louisiana close to the Texas line and thought plywood wouldn’t be hard to get, but I can’t find okume without shipping and man the price. I’d like to see some more of these built in the states and a large discussion on every aspect of the boat.Where do you guys find the aluminum pipe at? I will be building it on a small budget. My only gripe so far is the plans are in Metric and I will have to figure that out. Maybe he’ll make us some in imperial so the build is easier in America. Keep sailing guys.
Hi Gene,
Thanks for sharing! Here are a few thoughts:
1) Ask some local wood/builder supply stores if they ave any “luan made with waterproof glue.” It’s a little heavier than okume but a lot cheaper and just as good for building a daysailer such as Little Tri.
2) As a local welder about where to get the metal piping? All of the welders will know where to source the metal locally for the best price.
3) Invest in a good metric tape measure (you can get one pretty inexpensively on Amazon). You’ll be glad you did.
I have designed Little Tri. Thanks for buying the plans. I think Chuck from Duckworks was addressing me about imperial conversion. I know it is a psychologic problem. But metric is easy. You use it anyway every day! Your money system is metric. In 1 dollar has 100 cent etc.
Before you start building get a member of the very active K-designs forum. It is a restricted forum for plans owners. There you can find a lot of information concerning the construction of Little Tri. The video of the Tri with the Junk rig is built near you as far as I understand.
Do not change anything. Because it is a proven design. I addressed the concern about the lee board case already. Send me an email and you will get the amendment.
Cheers
Bernd
Mr.Bernd, and others, Thanks for the info. I wasn’t aware you had the K-designs forum. I will join up. You are very thoughtful offering your knowledge. The more I study your design, the more I like it. Thanks for the info that gets me going in the right direction. Yes I found the guys junkrig boat and I am checking out his videos. You guys alright!