Folding arm materials - Any reason not to use Aluminum?

[spidennis]

Originally Posted by Corley

Heres a photo of a friend of mines trailerable pod cat 28' he welded his beams up in stainless with custom fabricated bearings for folding the hulls against the pod hulls are foam/kevlar composite. Its designed to be a cruiser with a custom unstayed aero rig. I'll see if I can get some better photos next time I'm down there. It's beautifully constructed and has some innovative solutions on board.

AeroRig? I just started a thread on that .... if you get some more pics please add to that thread! and tell me more about it if you can ..... thanks!

Biplane AeroRig Cat?

[Corley]

Ian designed and built the boat himself he has a background in aircraft engineering. I've seen the plans for the boat and they are as detailed as most stock plans. It has an outboard in a pod and a single unstayed carbon, custom designed (by Ian) aerorig style mast. I was surprised how spacious the pod was when on board there isnt much intrusion by the beam hinge where it meets the hull. I'd say the interior has slightly less useable space than say a F22 trimaran well organised though to make the most of the space. The boat has it's rudders in cassettes that can be fully retracted. I assume it has daggerboards in the hulls not a surface piercing foil as theres no case in the pod. He has built the mast but it's not with the boat we are thinking of having him speak about the boat at one of our club meetings I'll take along a video camera if he does.

[spidennis]

Originally Posted by Corley

Heres a photo of a friend of mines trailerable pod cat 28' he welded his beams up in stainless with custom fabricated bearings for folding the hulls against the pod hulls are foam/kevlar composite. Its designed to be a cruiser with a custom unstayed aero rig. I'll see if I can get some better photos next time I'm down there. It's beautifully constructed and has some innovative solutions on board.

"trailerable pod cat 28' " and it folds? I'd sure like to see more of this boat! Especially the folding part! This sounds like the perfect Texas Coastal Cruiser for me! Offshore or in the bay and ICW, pretty mcuh go anywhere, now that would be the cat's meow!

[basil]

Re folding system link

Try this one

http://smalltrimarans.com/blog/?p=4039

[old dog]

Originally Posted by Jetboy

Warwick,

I think they are very similar. Farrier beams are more like a closed tube cross section while the Kendrick is more like a channel. I'm not sure there's any meaningful advantage to one over the other. The geometry is nearly identical. If you're going that route for folding, there's really only one a small window of linkage geometry that will work.

Of course that's assuming you're going to rely on fixed length linkage members and fixed connection points.

Channels tend to twist compared to RHS or tube.

[warwick]

I agree with old dog as there seams to be little difference between the Ray Kendrick and Ian Farrier folding approach. The approch by TNT 34 trimaran may have improvements in the future, by using a combination of folding and sliding, but may require time for devolopement. The TNT trimaran can be found as thread else where.

[Jetboy]

This has been a great learning thread for me. I've seen a lot of ideas I hadn't previously seen before.

As it turns out, I've found some free access to a water jet to cut whatever I want. I have to pay a small fee per mm of cut, but it's basically free. The big downside is that the table isn't very big. It's only 4' by 4', so that pretty much eliminates the ability to cut the arm beams unless I use two pieces for each one.

The funny part is that the more I consider the options, the more I end up back at the two most common: the original planned fiberglass or round aluminum tubing. I've still got a bit of time before I need to decide and a lot to learn.


Has anyone ever seen a tri with adjustable dihedral? I think it would be very nice to have for a cruiser type boat. Especially if, when stopped for fishing or something you could lower the amas so that they are both supporting the boat and give a lot greater stability when not under sail.

[guzzis3]

Originally Posted by Corley

Ian designed and built the boat himself he has a background in aircraft engineering.

Is that a swing wing folding system ? or something else ?

[Corley]

The hulls swing back against the pod a bit like the dragonfly trimaran.

[oldsailor7]

Quote:-
"Has anyone ever seen a tri with adjustable dihedral? I think it would be very nice to have for a cruiser type boat. Especially if, when stopped for fishing or something you could lower the amas so that they are both supporting the boat and give a lot greater stability when not under sail." Quote.

From my experience with Piver trimarans, which have immersed amas, there is no more special "Stability", or resistance to "Rocking" as the waves pass under the boat. This was especially bad on the Pivers as they had V section amas.
On a Tri with dihedral, one side of the boat can be "Ballasted" by weighting with a heavy object (such as sailbags etc), or do your fishing from one side by sitting on the ama. The boat then acts rather like a narrow Catamaran.

[warwick]

A similer approach was used on the malcom tennent designed catamaran, Streaker. Where the hulls swung back against the pod or the pod swung forward depending on view point.

[buzzman]

This guy in FL has built a different system, horizontal swing like Draglonly, but low tech and low cost KISS principle.

OK, so his rig is weird and super-simplified for his specific usage, but his claimed 2-3 mins to launch is mighty impressive, and the hulls can be unfolded on the move, not just on the water.

Interesting approach, at least.

http://www.diy-tris.com/2012/5-close-ups.htm