Why so few...

On smaller sailboats with a trampoline you can use a long pole that sticks through both hulls. If you use toggle clamps which takes no time at all to tighten or loosen to hold the beams, then you can float the hulls together and put a short pole through both hulls to hold them together. The beams with the trampoline can then be turned 90 degrees to lie on the hulls. If you use a removable hook-on winch you will have to use two lines in a V to pull the hulls towards each other simultaneously, insert the short pole and remove the long one, then off to the trailer.

 

With the Macgregor 36, in the closed position it uses 2 short beams to keep the hulls upright, you launch and retrieve like this and then replace them, one at a time with the full length beams which you fully bolt in on one end and leave the saddles loose on the other so you can slide it apart. It works but is a pita as the saddles bind up as the hulls rock with waves or you don't go out evenly and then when you do have it open and bolted up you are faced with 10ft of open space over water where you have to install the tramps. Oh, and you needed to install the chainplates , mast base, and dolphin striker over the beams as you assemble it. I modified mine heavily to assemble it on a telescoping trailer, I could do everything myself except moving the mast beam into place.
I have also worked on a model that allows for opening and closing a cat by just pulling on a line, the tramp and net stay in place and the geometry allows the mast to stay up so the boat could be kept in a marina berth at any percentage of beam, ie, it doesn't need to fold up to trailing width. It works well on the model but I need to actually set up a real boat with it, maybe an old beach cat. I would need to have the engineering done to use it on a full size boat. I designed it for an 8.5 meter cat design I have been working on sporadically. I believe a decent folding system for a cat to be the holy grail.

Steve.

 

If I were building a folding cat, I'd use two perpendicular axis folding beams. The two folding axis models are very controlled and would allow the folding system to work in a controlled and stable manner even in waves. Go to a hardware store and play with a bosch glider.

 

You said it ! And it's very possible as well.

Jetboy, I hate it if someone thinks of something before I do That is a good idea, the problem is to make those hinges strong, and small enough to be a decent size. The problem with all hinges is that the connection is only half of one beam width, and half of the other beam width. If you use the length of a deck to do the hinging, then it is not a problem, but on a relative narrow beam that is a point to consider.

If you look at cat2fold, it works on the same principle, the beams hinge forward and the deck holds it horizontally firm. Never the less, a good idea, I like it a lot.

The parts must always handle without requiring excessive force, we get old and the stuff gets heavier by the day. Oh yes, and we don't have time so everything must happen right away and immediately

 

Neat, but, how do you reconcile mast steps, nacelles or centre cockpits ?

My thoughts have always been around the Farrier type mounted back to back on a central fore and aft nacelle, bow sprit at front, motor pod aft, mast step and esky in the middle. Admittedly it might not minimise folded beam.

 

Oh !
I'm going to go look at that "axial glide" in the toolshop !

"like"

RR

 

Here you go:

https://www.youtube.com/watch?v=I10K3N-UCnY

 

For a cat you want the stand alone mast in the stern so you can have two masts, one in each stern and double the sail... Ok I know it's on a tri, but you do it twice on a cat.

The cockpit is a joystick you can have anywhere you want, even inside the hull. Don't you Ausies steer with electrics

Just to lessen the confusion The sail does get a boom, it gets fitted on a ball joint just before the furler and the claw goes to the end of the boom to keep the foot flat. My arms got way too thin to hold the sail. Oh and the Dutchman who tried to catch us with his big mono, but couldn't came there and said he saw this rig all over in Africa, every second moontoe there has one.

 

Dammit, you could never again saw a piece of wood without thinking of launching

 

Here is a vid where we took it out the last time... with the boom.
https://www.youtube.com/watch?v=pEYyCq92mnU&list=UUBkmmj6aKYE3532VQGi4Xgw

 

These things might be useful. They can be synchronized mechanically or electronically and form a rigid column when extended. They are stainless and about $400.00 for the one shown with self contained step motor. They make other larger versions. There is a video on u tube that I found amazing.

 

That's funny. One of them looks just like a Coke can. Over here they are made from aluminium.

 

Timothy, can you provide a link ?

I couldn't find them

 

Try http://www.pacospiralift.com/i-lock-en.html

 

you do have to look at the fine print. Can be easily set up by 2 people is a whole other show than can be run by 1. Some of these tris can be launched by one person. The only cat I know of that did that, was the Gougeon 32, which was arguably the most launchable boat of all time.

Some of these folding designs are not stable through the whole process of launching, they may be good folded, and unfolded, but not good in between. Another issue is the usability in the folded and unfolded mode. Can you canal motor, the folded berth.

If you make a boat, folding is often about the same effort as the boat is in terms of added time for the folding junk, and a trailer. In most cases it isn't used, though some people do.

There are increasing restrictions on what you can trailer. I just reviewed the new Ontario rules, which were wide open until recently. It has all of a sudden become a 1500 dollar a year, two vehicles inspected per year nightmare. One guy who sells trimaran plans in the US, and trailer plans, has said he no longer thinks they are practical in the US environment. Of course a lot of people do some pretty heroic stuff. But he figured most of his boats needed up grading to brake trailers, and the regs on those are super costly.

I also recently tried to buy a large trailerable tri. Turned out an abosolute nighmare, the whole thing now has to go through the vehicle registration process, and that ads additional cost, and uncertainty. And the boat is now subject to the rules of each state it goes through. The problem is that states and provinces are well aware of the needs of their boater, but when a designer decides to make a package as large as a tri can be, it is pushing a lot of rules to the max.

You can configure tris fore and aft to have separate accommodations. But I am sceptical of any attempt to provide true privacy in such a small space for two adult couples and their needs. Wharram had it right. One guy and a crew of naked people scattered all over the deck.