PDA

View Full Version : Small Wooden Cats



boatbuddha
02-12-2010, 03:55 PM
Anyone have any experience building one of the smaller wharram designs or a similar catamaran? I'm thinking of something like the Hitia 14, or Ray Aldridge's Slider.

slidercat
02-12-2010, 04:33 PM
Maybe I shouldn't jump in here, but I recently posted a page (http://slidercat.com/blog/wordpress/?p=208) to my blog about some guys who are pretty far along in the Slider build process.

In the first pic of Dean's build, you can really see the workboat heritage, I think.

boatbuddha
02-12-2010, 04:49 PM
Maybe I shouldn't jump in here, but I recently posted a page (http://slidercat.com/blog/wordpress/?p=208) to my blog about some guys who are pretty far along in the Slider build process.

In the first pic of Dean's build, you can really see the workboat heritage, I think.

Thanks Ray how's work coming on Slipper? I really like the idea of a cartopper.

tmoll
02-12-2010, 05:28 PM
I find the K-Designs Eco cat a very interesting small cat camper design. Sleek looking and a pretty functional "cabin".
www.ikarus342000.com

If you don't find it too ugly, the Hot Chili which can be found on the Duckworks site under "plans" would be a fairly quick and easy build and uses a beach cat rig.
I have no first hand experience with either, however.
Tom

trefor
02-15-2010, 09:33 AM
Here's some build pics of a Hitia 14 on Flickr. You might be able to contact the guy that built it and ask him questions directly. The Hitia 14 is a great looking little catamaran and from the pics, looks like it can be cartopped. I wouldn't mind having one, myself.

http://www.flickr.com/photos/bartloeff/sets/662781/

-Trevor

slidercat
02-15-2010, 01:36 PM
Thanks Ray how's work coming on Slipper? I really like the idea of a cartopper.

It's almost done. Bear in mind that Slipper is a radical simplification of the ideas in Slider, what with no boards, barndoor rudders, a single sprit sail, and so forth. It might not work worth a damn. With Slider, my only departure from very conventional design was the in-hull seating. With Slipper, everything is pared down to the absolute minimum I thought I could get away with.

By the way, Dean sent me some new pics of his build, and I put this one up:

http://slidercat.com/blog/wordpress/wp-content/gallery/otherboats/honu1_0.jpg

Bill Huson
02-15-2010, 08:12 PM
Almost done with a "Pixie", WB plan 400-083. A 14' car top beach cat, knocks down to hulls and parts using plug in beams. Hulls weigh 40-45 lbs each. S&G hull construction.

Right now I'm down to installing hardware which will be removed for finish varnish, and making several rigging parts including the sails. Tramp is done. All up weight probably 160 lb. The beach cat design has no daggers of centerboards which allow for easy beaching and shallow draft operation which is nice in Down East NC since our sounds are skinny water.

trefor
02-16-2010, 09:13 AM
those blue hulls look great with the tanbark sails.

-trevor

slidercat
02-16-2010, 12:57 PM
Bill, I think Pixie is an excellent home-built beach cat-- it'll be at least twice as fast as Slipper. There will be a lot of other differences too. Pixie has a very well-thought-out kick-up rudder system, but Slipper uses barn door rudders attached to skegs, for simplicity. Pixie has efficient rounded V decked hulls, while Slipper has dory-like open hulls. Pixie uses a powerful sloop rig, while Slipper uses a single sprit sail, which I'm trying to rig without a boom, so it can be brailed up instead of lowered. Pixie uses a tramp, while Slipper has a hard deck.

Slipper is kind of an anti-beach cat. I'm trying to take the approach to cat design that Jim Michalak takes to monohull sailboat design.

I guess a reasonable question is why? I don't know, unless it's just that while I'd be interested in owning a lot of boats, I'm only interested in designing and building boats that haven't been done before. Of course, I may end up with an original piece of crap, but that's a chance you take when you try something new.

http://slidercat.com/blog/wordpress/wp-content/uploads/2009/07/slipfloat.jpg

Bill Huson
02-17-2010, 10:41 AM
Well, Ray, I think the Slider is a rather cool design, and appears stable. One thing for sure about the Pixie - Darling Daughter is going to get WET! My adventure is building almost everything on the boat. For lashings that require tension, shrouds and whatnot, I made 1 1/4" deadeyes. After pricing sails and tramps I decided to make those as well. Tramp is done, sail lofting is next. And after pricing blocks I'm going to make my own blocks also. Fun! It all may work - or not. When I shove my daughter off for the maiden voyage I'll have a camera ready to catch those *crack* and *kapow* moments if some of my handiwork decides to puke :eek:

slidercat
02-17-2010, 12:07 PM
Thanks, Bill. Sounds like you're squeezing all the fun possible out of your build. I predict your daughter will love her Pixie.

wtarzia
02-17-2010, 02:17 PM
I admire these designs, but the akas (crossbeams) seem rather 'windagey' though perhaps light. What is their rationale? -- Wade

Bill Huson
02-17-2010, 03:55 PM
I admire these designs, but the akas (crossbeams) seem rather 'windagey' though perhaps light. What is their rationale? -- Wade

I'm sure the designer will address that question, but I'm thinking I-beam style to save weight.

slidercat
02-18-2010, 10:00 AM
Wade, Bill's right. The idea was to reduce weight. Slider, the 16' beach cruiser, uses 2 X 6 solid crossbeams, so not too much windage, but they're heavy. Slipper, the little 14' cartop cat, uses I-beams that rise to 9 inches in the center of the span. They might be more of a concern, windage -wise, but a) the boat will not be very fast and b) I can cut holes in the webs.

wtarzia
02-18-2010, 10:11 AM
OK, gotcha. I made my beams from solid Douglas Fir laminates, approximately 3 x3.5 inch, tapering toward the ama, with half-inch radiuses to remove some edge from the wind. Strong, low-profile, but heavy, and always on the lookout for a different way for my 24 footer in the planning stage (more like the ambition stage). Some Wharram beams look interesting -- some of them seem to have a triangulated structure, somewhat aerodymanic as the slowing edge meets the wind, but they look reasonably light (at least the ones I glanced on on the 26 foot Wharram catamaran at the Mystic WB Show). --Wade

Dan St Gean
02-18-2010, 04:23 PM
Another way to make beams lighter is to use the tougher strips on the outside and the lighterweight wood like WRC on the inside.

I wonder how I beams would work for a cat as they tend to "walk" upwind if the beams are less than stout. The I would be super strong in one plane, but not so much in twisting resistance--something I have seen personally. I broke the H18 main beam on my double Tamanu as a result of this twisting force.
http://wikiproa.pbworks.com/f/1246406365/Paul%27s%20mott.jpg
It's another reason lots of cats have three beams too. If you look closely you can see the tramp not inserted into the port side--the reason? A cracked "luff groove" in the beam.

Gary Dierking recommends box beams for his designs.
Wharram usually has triangular shaped beams.
A few ways to skin a cat(no pun intended).

Dan

slidercat
02-18-2010, 11:46 PM
I would say I-beams are well-proven, as they were a feature of most of Thomas Firth Jones' multihull designs, and he took a couple of these boats offshore.

I'm no structural engineer, but as I understand it, torsion analysis of I-beams is in practical terms limited to warping. I have a vague theory that because there are at least two I-beams in most conventional crossbeam systems, their individual resistance to warping is additive. In other words, the warping forces are resisted by both beams. I could be, and probably am, completely wrong. Still, Jones' I-beams have been strong and durable.

One great advantage plywood and timber I-beams have over wood box beams is that they are less likely to suffer from rot, and if they do, it's easier to spot.

Typhoon
02-19-2010, 05:22 AM
These are a fantastic fun little boat and were originally built in ply:
http://www.papertigercatamaran.org/

Regards, Andrew.

Dan St Gean
02-19-2010, 09:31 AM
I would say I-beams are well-proven, as they were a feature of most of Thomas Firth Jones' multihull designs, and he took a couple of these boats offshore.

I'm no structural engineer, but as I understand it, torsion analysis of I-beams is in practical terms limited to warping. I have a vague theory that because there are at least two I-beams in most conventional crossbeam systems, their individual resistance to warping is additive. In other words, the warping forces are resisted by both beams. I could be, and probably am, completely wrong. Still, Jones' I-beams have been strong and durable.

One great advantage plywood and timber I-beams have over wood box beams is that they are less likely to suffer from rot, and if they do, it's easier to spot.

That seems to make sense. Some of his designs have three beams as well. I'm currently reading his New Plywood Boats which is really insightful--might have to pick that one up for myself after I return this one to the library.

Bill Huson
02-19-2010, 11:27 AM
Beams on the Pixie are box beams. Top & bottom 20mm thick full width of beam, and the sides are 15mm. The wood is cypress, box epoxied and tacked together with bronze nails. I doubt the wide spaced nails do jack for strength but they did hold the slimy epoxy mess together while it cured. I have not weighed the beams but they are fairly light.

uwhilna
02-25-2010, 06:25 AM
Anyone have any experience building one of the smaller wharram designs or a similar catamaran? I'm thinking of something like the Hitia 14, or Ray Aldridge's Slider.

Last year I helped with the moulds for a glass version of the Jim Young Kitty Kat for our local yacht club. Its just about ready for launching and I will post a pic in a week or two, this is from Jim Young's website

Kitty Cat

The Kitty Cat came along in 1958 when John Peet an Auckland School Teacher wanted to build a yacht to compete in the Australasian 12ft unrestricted Silasec Trophy and boat builder/designer Jim Young a former Sanders Cup Champion who was now an established boat builder in Birkenhead suggested that a cat might do the job. Between them they built and experimented with the Kitty which not only won all its races but one, when the mast broke, Kitty Cat caused the racing committee to exclude catamarans from all future Silasec rases. You see in those days the only other cats sailing were slow and the yachties of the day didn’t take much notice when John told the Q class people that he was building a cat and would they mind if he sailed in the trials to select the Auckland yachts which would race against the Sydney 12fters in their biennial contest? The Q class yachties said they would not mind. “Please go a head we are an unrestricted class.” They doubted that a catamaran as small as 12ft would “go.” The Kitty certainly did “go,” she cleaned up the Q class and by the time the trials had finished she was whipping the fleet by 5minutes. Well, the Aussies were not happy, Kitty won the trophy and cats were then banned from the unrestricted class saying that racing a cat with a monohull was ridiculous. By this time there were as many as 20 Kitty Cats racing, so each went their separate ways and John bought himself a Mistral. The Kitty Cat whipped the 18fters of the Day claiming the first Cock Of the Harbour. Funny how history repeated itself in 1987/88 in the AC 30 years later.
http://yachtyakka.co.nz/wp/wp-content/uploads/2008/07/kitty1_1041.jpg

http://yachtyakka.co.nz/wp/wp-content/uploads/2008/07/dsc02984.jpg

http://i538.photobucket.com/albums/ff350/fakeperson/Photo0026.jpg

AnalogKid
02-25-2010, 06:05 PM
Uwhilna, is that bottom photo from the Auckland designers exhibition that was on at the Devonport yacht club last year?

I didn't notice that bit on Jim Young, but then I was mainly looking for the trailer-sailer designs that were on display.

uwhilna
02-25-2010, 06:17 PM
Its off the wall at the Titahi Bay club, I will post some pics of the fiberglass and an earlier wooden build in a day or two.

donald branscom
02-25-2010, 09:02 PM
Now I will put "Slid'n and Glid'n on my music system. A BB King instrumental song.

uwhilna
02-26-2010, 03:28 AM
The Kitty Kat fiberglass version...

http://i538.photobucket.com/albums/ff350/fakeperson/Photo0078.jpg

http://i538.photobucket.com/albums/ff350/fakeperson/Photo0077.jpg