Construction of solar arch?

Surely a pedant would say that the thickness will depend on the spec you buy? That was almost the opposite of pedantry, it was a sweeping generalisation
He didn't say he's a pedant, he said "I'm a pendant". I should think if you're a pendant, it's matter of enormous importance so you don't fall in.

Something like #17 is close to what I have in mind. thank you.
 
Morning Folks,

So looking at doing a solar arch and possibly something to hang my avon round tail off with a 2.3 horse engine. The predominant reason for the arch is for solar (1 panel, ridged 1500mm x 800mm). I am toying between having a go myself (never welded or bent pipe) or go get someone to do it. I have a 282 gibsea (so little tub 2.8 ton) I mention this in respect to the weight. I am thinking of something like what my neighbour in IOM has done. Bolt to the aluminum toe rail (I have some paste to avoid corrosion, but will probably add a plastic spacer). The crude drawing is to give some idea of design, basically 2 of those then bolt them together with fittings or welds. In summary a 6000 mm pipe with 1000mm vertical then a bend and 1000mm then 2000mm horizontal then same down the otherside (roughly). The width of the boat is 2860 toe rail to toe rail (the rear one is a bit smaller as the aft tapers).

So the questions are do I go with Seamless Tube 316 Stainless Steel Metric - 6000MM, 25MM OD X 20MM ID (2.5MM Wall or do I go with the equivalent 1.5mm or I have just noticed they do a 2mm.
Thinking I will use 18m (max) of pipe so 1.5mm would be 0.88 * 18 = 16kg, 2mm would be 21kg and 26kg.

1. Considering the size and weight of my boat or is it irrelevant and I want an arch that does not wobble. I could potentially add some bracing to the push pit similar to what we see in the example pic below on the port side, thoughts?

Any advantage (maybe weight) going aluminum (not checked out prices) Sailboat Arch | Tower In A Box | Atlantic Towers I saw this made from 50mm 40 Schedule, looks v solid, but I think 50mm pipe looks a bit stupid on a 28 ft boat maybe? I think I am set on 316, but thought I would mention

2. With that in mind, bending the chosen pipe am I setting myself up for a hiding and would do better to make a frame in timber and get someone to copy it?

3. I assume we can get a marine like polish on this said pipe if its welded etc?

4. The height I set at 1900mm from the toe, gives me about 100mm clearence when I stand on the chair, any thoughts on this?

5. Side point from a water penetration point of view I assume it is better not to put holes in the frame to prevent this or it doesn;t really matter?

Thanks in advance, I just want to make sure before I spend 700 pounds on pipe I know what I am doing!

Kind regards


Karl
 

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You may struggle to bend 25mm stainless with a plumber's tool. Especially 2.5mm wall thickness, which I think may be overkill for your application.

My solar arch is all 25mm X 1.5 and I have a 3.3m span, with 800w of rigid panels on top.
 
Ours is 25mm tube with 2mm wall, fully welded and although good for what it needs to do would not be good enough to hang dinghy off, it would wobble, if I did it again would use 32mm tube, don’t think you would easily bend 25mm x2mm tube neatly
 

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Ours is 25mm tube with 2mm wall, fully welded and although good for what it needs to do would not be good enough to hang dinghy off, it would wobble, if I did it again would use 32mm tube, don’t think you would easily bend 25mm x2mm tube neatly

That is interesting, thanks for the response. What is your span about 3m? It looks like yours was bent, I assume you took it to a shop to do? If I look at Schedule 40 1 inch its 2.5Kg per meter which would add about 45 Kg to the back of the boat. I am also thinking 28Ft boat is it overkill I could add some bracing to the back.

Cheers

Karl
 
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You may struggle to bend 25mm stainless with a plumber's tool. Especially 2.5mm wall thickness, which I think may be overkill for your application.

My solar arch is all 25mm X 1.5 and I have a 3.3m span, with 800w of rigid panels on top.
Thanks for the advice, glad I posted!
 
That is interesting, thanks for the response. What is your span about 3m? It looks like yours is bent, I assume you took it to a shop to do?

Cheers

Karl
Span just over 3m and fully welded and polished, it was made by a mate who had a fabrication company working mostly making food factory equipment, the angles are welded long radius bends cut back to fit required angle, tig welded and polished. Any good stainless welder could do this, the hard bit is getting the angles and dimensions to be made away from the boat. Materials cost me £300 and labour £500 at mates rates. The 25mm tube was chosen to match the push pit rail is was to fit off for the back rail. You will note the side rails are not quite right as the measurements were a bit off but was not worth redoing it
 

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25mm x 1.5mm 316 tube, a pair of 100w panels and an emergency VHF antenna, nothing complicated, no feats of fantastic engineering, no multitude of brace and/or guys and supports. Been there 4 years, regularly used as a hand rail for getting on and off of the boat or for leaning on when underway.

View attachment 115166

If we want to hang the dinghy off the back or add other things, we design something different and use appropriate materials. Swing out davits, etc, so bigger tube, built into the pushpit (not quite finished in this picture) for additional strength.

View attachment 115167

Horses for courses, the OP said he only wanted to mount his solar panels.
Hey Paul, I am more lost than before I posted on this! I have one person saying they would do it in 32mm if they did it again and another saying they are super happy with 25mm. Mine is only a little tub so I dont want it to look ridiculous, I would also like to attach to the tow rail to avoid drill the deck. Looking at that moody 376 that looks pretty solid construction. Is that 32mm? pipe?

Cheers

Karl
 
In fairness if I was starting from scratch I would have gone bigger. But I had a whole bunch of 25mm already so I just made do with it. However this is on a much bigger boat.

Bimimi frames are often 22mm... not a lot of weight on them but they do get used as handholds etc...
 
3. I assume we can get a marine like polish on this said pipe if its welded etc?

I’ve been a bit more involved in stainless fab for the boat recently (commissioning some from pros and doing some DIY) and polishing is a significant part of the cost/time.

With my recently acquired beginner skills, I’d need probably an hour per 100mm to mirror polish stock bar. That’s with a machine sander polisher (wet sanding and then compounding).

Our new chainplates (so pretty small area) were £60 (of £200 total each) just to polish. The company used electro polishing and finished after welding by hand. I reckon a quarter to third of total labour cost (at least) would be polishing.
 
I’ve been a bit more involved in stainless fab for the boat recently (commissioning some from pros and doing some DIY) and polishing is a significant part of the cost/time.

With my recently acquired beginner skills, I’d need probably an hour per 100mm to mirror polish stock bar. That’s with a machine sander polisher (wet sanding and then compounding).

Our new chainplates (so pretty small area) were £60 (of £200 total each) just to polish. The company used electro polishing and finished after welding by hand. I reckon a quarter to third of total labour cost (at least) would be polishing.

So start off with a polished bit of pipe then I would say! Any good suppliers of marine fittings, specifically the end lugs would you recommend?

Cheers

Karl
 
So start off with a polished bit of pipe then I would say! Any good suppliers of marine fittings, specifically the end lugs would you recommend?

Cheers

Karl
A quick Google suggested the price of mirror polished stainless (sold as ‘handrail’?!) isn’t as horrific as I’d imagined!

Or you could find a local electro polishing place and ask them to quote for polishing the stock (generally done before welding anyway)?

No specific knowledge of suppliers but I’d imagine most of the standard 316 fittings are mass produced in the same place/way.
 
I have no idea about pipe thickness and strength, our solar arch holds the roof up

IMG_0091.jpeg

I see these devices made from tube and I wonder if, when push comes to shove, they are seen as a way to access the boom end (when a reefing line locks up and the crew are in panic mode).

Jonathan
 
Hey Paul, I am more lost than before I posted on this! I have one person saying they would do it in 32mm if they did it again and another saying they are super happy with 25mm. Mine is only a little tub so I dont want it to look ridiculous, I would also like to attach to the tow rail to avoid drill the deck. Looking at that moody 376 that looks pretty solid construction. Is that 32mm? pipe?

Cheers

Karl

I'm still happy with 25mm tube, it just supports the solar panels, never intended to do anything else.

The Moody arch is indeed 32mm tube. That carries a pair of 250w solar panels and swing out davits for the tender. 25mm would be inadequate here, IMO.
 
I'm still happy with 25mm tube, it just supports the solar panels, never intended to do anything else.

The Moody arch is indeed 32mm tube. That carries a pair of 250w solar panels and swing out davits for the tender. 25mm would be inadequate here, IMO.
One last question, what thickness of the walls is it on the 32mm, 2mm 3mm or 4mm? I assume you have a hydraulic bender for that?
I did get in touch with clarke and they said their hydraulic bender only works with 4mm thickness or above otherwise it creases the pipe

Thanks again

Cheers

Karl
 
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I think >30mm is typically 2mm wall as standard. Without wanting to speak for Paul, I’m not personally convinced by beefing up the wall thickness beyond the ‘standard’ for the chosen/given diameter.

I have some very thick wall but smallish diameter tube I was generously given by a boatyard neighbour. It’s ‘nice and thick’ - but weighs a tonne for what it is and looks a fiend to bend. It gives the sense it was made for something else. Thus I haven’t yet found a use for it!
 
My ongoing project uses 22 mm x 1.5mm tube and will resemble PaulRainbow's top pic in Post #16.
Only supporting 90W worth solar on 27 foot boat.

I was a bit horrified at the weight and heft of the tube when it arrived. Even at 22mm, way over spec'd for my needs I'm thinking. I’d go thinner wall if available.

Then there’s the bending issue. Hard to find definitive information but concluded it would be too difficult by hand, or find some kit to buy/hire, so tried to find a local workshop. No luck - 'can do 25mm fine but not got the kit for 22mm'. Eventually had to go over to Poole to get it done.
 
One last question, what thickness of the walls is it on the 32mm, 2mm 3mm or 4mm? I assume you have a hydraulic bender for that?
I did get in touch with clarke and they said their hydraulic bender only works with 4mm thickness or above otherwise it creases the pipe

Thanks again

Cheers

Karl

2mm is fine, no need to go thicker. I don't see where thicker offers any advantage in this case. I would question fixing to the ally toe rail and hanging a dinghy from it though.

I'd suggest one of two options, either 25mm tube, bolted to the toe rails and only carrying solar panels, or if you want to hang the dinghy from it, go for 32mm tube but bolt it securely to the deck.
 
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