Why Stainless?????

[Tracyandkimo]

I have 2020 Lagoon 46 with the factory solar arch w 4x120w panels and another identical 4x120 on our flybridge. We want to add solar to the arch. Its design seems to be more concerned w/aesthetics than function. We want to replace or modify the present arch to add as much solar as we can practically fit. Why do sailors use stainless so exclusively? Why not aluminum or composite/carbon?
Even w/modest carbon skills such as what I have, using readily available carbon tubing, an all carbon arch could be made at a fraction of weight and about the same costs. Is there any compelling reason not to use carbon for such a structure that really doesn't need to withstand otherwise devastating forces.
Happy Holidays!

[Rucksta]

Where are you buying carbon at about the same cost as stainless?
I want some and then some more.

[jimbunyard]

No reason you can't; carbon/epoxy is more labor-intensive to achieve the same strength.

And their is a probablility of more maintenance concerns, though these can be minimized with proper construction and the use of quality materials (not necessarily the most expensive) when finishing the arch.


Lagoon, as well as other production manufacturers, use stainless because it fits their primary business objective, profits for their shareholders...

[Tracyandkimo]

I've purchased both carbon tubing and plating online from several sources and a quick online search suggest an adequate carbon would be 10-20% more than stainless but in my situation, the labor be much less and I would enjoy the endeavor.
This assumes that my initial boat yard engineering design of 1.75 OD w/wall of 1/8 would suffice. I can't imagine that if properly designed and executed, this wouldn't suffice but I would certainly confirm prior to beginning.

[Benz]

If hit or subjected to enough bending force, carbon tubes can snap, leaving sharp ends to impale yourself on. That's why racing boats only briefly dallied with carbon stanchions.
Stainless will bend without snapping.
Aluminum is my favorite, but my guess is that Lagoon uses stainless because it's shiny and easier to weld than aluminum.

[Tracyandkimo]

certainly concerns, but with proper design and execution, wouldn't be an overbearing concern. Having raced on all carbon boats for decades, i'll taken carbon over SS every time. Carbon failure does occur in a catastrophic manner but the margin between failure loads and available strength would be wide.

[MikeHoncho]

How’s carbon fiber with UV?

[Benz]

Originally Posted by MikeHoncho

How’s carbon fiber with UV?

That's all about the resin. Something must be used to protect the resin from UV or it will yellow and degrade with time. Some folks go as simple as varnish, but there's some UV-stabilized epoxy clear coats out there (for those who want to see the carbon), plus the whole range of paints.

[more]

Originally Posted by Tracyandkimo

I have 2020 Lagoon 46 with the factory solar arch w 4x120w panels and another identical 4x120 on our flybridge. We want to add solar to the arch. Its design seems to be more concerned w/aesthetics than function. We want to replace or modify the present arch to add as much solar as we can practically fit. Why do sailors use stainless so exclusively? Why not aluminum

Aluminum is better for a solar arch. Because also solar panel frame is made from aluminum. But welding aluminium is more expensive and also need painting or anodizing

[Pete7]

Originally Posted by more

painting or anodizing

Paint will eventually fail. Spent years re-painting my diving cylinders. Stainless just needs a polish once a year.

The A frame on this rib was also aluminium and on a commercial boat not a problem being unpainted, but the owners of high end cats aren't going to accept that finish.

Pete

[nfbr]

Just got 3.6kw on my carbon arch. Outstanding. about 50kg all up for 200kg of panels.

[gonesail]

there are aluminum alloys that are strong and lighter than SS. usually you see these on fishing boats and the structures are welded. it would be good for a custom solar panel arch.

[Manateeman]

We TIG weld both stainless and aluminum. When stainless is welded in a commercial setting, the backside of the weld is shielded by argon. In a pipe, or tube, the ends are sealed so that there is a slight flow of gas to protect the weld area. TIG welding outside for both aluminum and stainless, requires the same argon coverage and it’s difficult to do with even a slight breeze.
Both materials require super clean material.
We’ve seen the interior of pipe and tubes in which the weld has failed because it was done by inexperienced welders, dirty material , wrong settings...but often, simply the lack of gas coverage inside.

Good fabrication shops are worth the additional money. The manatee crew tips their caps to any TIG welder who can do certified work as it truly is a skill.
Find a good shop. They will be happy to show you both good and bad welds.
Lots of videos on the web. Miller welding equipment and Welding tips and tricks are good sources.
Carbon Fiber? Much more money and we leave it to the race crowd.
Please remember carbon fiber is much more electrically conductive than most people know. Not exactly what you want to grab onto in a lightning storm.
Merry Christmas

[Tracyandkimo]

my initial thought was to use 2" OD w/a 0.125 wall, assembled w/West and painted to keep temps low due to West's sensitivity to heat and for UV protection. What profile did you use as your primary material? Although the weight savings are attractive, it's not my motivation for using carbon. It's a material that I'm proficient using for fabrication and I just want to get it done. The yards are so backed up w/high demand that the wait times are long and they are asking a premium.

[Tracyandkimo]

Manateeman, I agree about the disparity in welding skill! It truly is an art form. For me, Carbon is second nature and something I use routinely. The materials themselves are reasonable and I have the skill set to do the fabrication thereby keeping the costs well below what the fabrication shops are asking for stainless. I haven't priced out aluminum since I assume they are as backlogged as the others. As far as conductivity, in the event of a strike, we would likely have greater concerns than the solar arch