Outrigger canoe Ama design considerations

[fallguy]

Is it not true the goal of any outrigger is to increase stability?

And so; the best ouutrigger barely touches the sea? Or not at all unless the vessel tips?

And then doesn't this mean the design needs to be narrow and vee and streamlined with rocker to reduce the waterplane to the least needed?

All the items on my amas and akas were big box store; except glass n epoxy n some filler. The foam is pink polystyrene. To increase its shear; you sand it with 36 grit paper and then hotcoat it and use light 100g or 6 oz glass to keep it from falling apart or waterlogged. I don't believe I added a shear web, but maybe. I also used pvc tubing from big box for the ama/aka interfaces. Basically a cleanout tee. The akas are laminated strips of hardwood. No glass. Zoom in to see the connections. The reason for outriggers is this water can kill you in 2 minutes.

 

[garydierking]

Foam and Fiberglass Ama Construction https://amaconstruction.blogspot.com/2021/02/foamand-fiberglass-ama-construction.html

 

[pmudesign]

Foam and Fiberglass Ama Construction https://amaconstruction.blogspot.com/2021/02/foamand-fiberglass-ama-construction.html

Great find, thanks!

 

[fallguy]

Not a find; he is the author!

 

[cando2]

Hi Paul. Outrigger canoes and surf skis are two separate disciplines with strong cultures. If you adapt one to the other both cultures will reject it. A good way to destroy V10 resale value is to install added features. OC1 have reinforcement where akas attach, not so the surf ski. I ran approximately a 1" plus pvc pipe 8' long across forward of my foot pedals with a crab pot foam float fitted on each end. A thin strap (purchased at harbor freight) was wrapped around the hull and around the pipe at both sides and fastened across the middle with the strap end friction buckle. This acted as a balance beam to aid learning, with floats to keep from dumping constantly. The floats stayed clear of the water unless I tipped. Soft, easily compressed foam was installed between the pipe and hull on both sides to pad and increase friction. For me, this setup allowed me to learn more quickly w/out damaging my ski. I'll be adapting this method to produce and attach an ama setup this winter. I'll describe when I have more time.

 

[pmudesign]

Hi Paul. Outrigger canoes and surf skis are two separate disciplines with strong cultures. If you adapt one to the other both cultures will reject it. A good way to destroy V10 resale value is to install added features.

The V10 I have is one of the original models and has issues (some delaminations, and the footpads / pedals were frozen with corrosion). I bought it as a project for a fraction of what a new or recent used ski would cost. Although I don't wish to destroy the ski's original design or resale value, my top priority is to make it something I can use without too steep a learning curve.

I considered strapping some floats like you suggested and might still give that a try. But I still like the idea of turning my tired old ski into an OC.

 

[cando2]

Got it. Those details are helpful. The biggest issue is how to attach akas to the ski. Point loading of a machine screw and nut with a big washer on both sides on a thin ski laminate may not last long. Couple options come to mind: laminate a few layers of glass at spot you'll be drilling, or contact cement a purchased reinforced rubber patch with a ring like they use for inflatable watercraft. For me, flexible attachment points with slightly flexible akas are the way to go to mellow larger wave impacts. I had looked at some hardware and akas available on amazon. Are you aware of those? There are some amas of various types also. Had you looked into getting a used, possibly damaged ama cheap off an outrigger canoe forum?

 

[pmudesign]

Got it. Those details are helpful. The biggest issue is how to attach akas to the ski. Point loading of a machine screw and nut with a big washer on both sides on a thin ski laminate may not last long. Couple options come to mind: laminate a few layers of glass at spot you'll be drilling, or contact cement a purchased reinforced rubber patch with a ring like they use for inflatable watercraft. For me, flexible attachment points with slightly flexible akas are the way to go to mellow larger wave impacts. I had looked at some hardware and akas available on amazon. Are you aware of those? There are some amas of various types also. Had you looked into getting a used, possibly damaged ama cheap off an outrigger canoe forum?

First order of business for me is to repair the delams (I've already rebuilt the adjustable foot pedals). I believe the core is honeycomb so I'll probably add a layer of carbon fiber over the soft spots to stiffen them. I also bought two 4" inspection ports for access into the hull.

My current thinking is to build up the mounting points with glass & CF on the top and large plywood washers (3" diameter) on the inside. That will hopefully spread the load enough not to crush the core.

Then I'll shape a "bridge" from eps foam and glass / CF for the crossbeams to mount to. A friend's OC-1 uses 1.25" OD aluminum tubes for crossbeams so I plan on using the same.

I haven't decided how to mount the amas, but I may use something similar to what Gary did and use strips of rubber to secure it.

 

[pmudesign]

One thing I read was that a typical OC-1 ama weighs 2-3 lbs so my goal is somewhere around 5 lbs.

 

[pmudesign]

Oh, I also hope to use vacuum bagging wherever possible. I first tried vacuum bagging 23 years ago and the laminate came out much stronger and lighter than any other method I tried.

 

[cando2]

You've got some great ideas there, Paul. Sounds like you're having fun. Before long you can give us tutorials on what works and what doesn't work. Best wishes and keep us updated on your progress.

 

[fallguy]

If you look at my icy canoe pic; you can see I also use rubber inner tube lashings. If you tie them right; they are super great. Tie them wrong and they are useless.

 

[pmudesign]

 

[garydierking]

I would recommend mounting your crossbeams on pedestals like this Tahitian V1. There is usually a flat metal bar connecting them at the top for lashing.

 

[pmudesign]

I would recommend mounting your crossbeams on pedestals like this Tahitian V1. There is usually a flat metal bar connecting them at the top for lashing.

That's one direction I'm considering. If I go that route the aluminum tubes I was planning on using may not work well. Round tube on top of a flat bar. I'd consider using wood for the beams but the only species available to me are fir, poplar and oak.