Stern Arch Q. fabrication sequence

[Windswept-windy]

Members....I'm attempting to duplicate near exact stern arch of friends Hylas 46 to my Hylas 46. My question is on just one structure tube. That tube is (pic's below) the most aft outer 1.5" tube. My concern is one of two ways to tackle this tube. Stern beam = 13', Tubing is 20' long. One tube length will not span the whole length... will have to tig weld extensions to span total length.

Sequence 1.

Would you center tube length (10' at top), then measure (approx. 6.5') out to both 90* bends down. The remaining length of the down tubs would be approx. 3.5' on both sides. Then add (weld) extension tubs (bend) to meet flat plate mount on either side of stern?

Or... sequence 2.

Start tube at bottom with a 10' length, make bends at top of railing, continue up to top 90* bend, then continue with remaining tube to approx. 3.5' and stop.

Once two uprights were fixed....7' up & 3' horizonal connect (weld) both uprights with approx. 7' piece to join both sides.

I'm leaning towards sequence 2. as sequence 1. I would have to support top section while adding extensions to bottom of both legs.

I hope the above written description (some what difficult to describe) is enough to get my idea across. If not please ask away. Thanks in advance.


Note: I have the tig welder & tube bender....I will fabricate & spot weld project, then bring in professional welder to complete welds.

[coopec43]

"I'm leaning towards sequence 2. as sequence 1. I would have to support top section while adding extensions to bottom of both legs".

Why would you have to support the top section while adding the legs?

I must be missing something because you sound as though you know what you are doing but I would add the legs while it is laying down and then haul the whole structure upright.

[tkeithlu]

My thought went the same way as Coopecs while I was reading. Why are you not fabricating the part flat on the ground/floor? Just to be a contrarian, I think that a visible weld would be better on each side than at the top middle, and probably stronger.

[Windswept-windy]

Coopec43, tkeithlu...thanks heaps for your inputs!

Well, for starters, I'm difinately a newbie especially with SS & Tig but, I have figured out how to tack weld.

I have seen one other arch built here in the marina. Welder built a wood support platform (quite elaborate actually) that supported his rectangle frame that actually supports the panels. That wood frame held that solar frame exactly the way he wanted. (level ect)

That particular arch was only basically using straight vertical tubing for it's legs. Tad easier than what I'm trying to do.

My project has quite a few angles, bends and then miter cut into the landing pads.

This is the (I'm thinking) start at the bottom and work up?? The other reason is.... I'm working by myself, girlfriend can help me when she's not working which would only be on the weekends. Tuff working by yourself.

One other aspect is....where vertical tubes land on deck mounting pads, that pad has to be drilled out (within ID of tube, to let wires (solar, antennas, lights, dingy winch power cable ect.) to enter deck. All 4 tube anchor points will have electrical wires going through deck.

Just trying to figure out...best way to tackle this project and put as many eyes on it for suggestions. Thanks heaps! Don

[tkeithlu]

Your welder had a good point. Always put your work in a jig or hold it down before you tack, or you WILL end up with it not quite fitting together. That said, your jig can be in any convenient configuration. For tacking (you are not going all the way around) flat on the ground is a good start, and your jig can be carefully placed bricks or what I used when building my boat - a 16' x 16' plywood table with parts and blocks held down with wood screws.

[Windswept-windy]

Originally Posted by tkeithlu

Your welder had a good point. Always put your work in a jig or hold it down before you tack, or you WILL end up with it not quite fitting together. That said, your jig can be in any convenient configuration. For tacking (you are not going all the way around) flat on the ground is a good start, and your jig can be carefully placed bricks or what I used when building my boat - a 16' x 16' plywood table with parts and blocks held down with wood screws.

G'day Keith.....yep, your quite correct. The wood structure I mention above was placed at the final heigth above the deck (stern). On top of the wood structure, he placed his actual rectangle tubing frame that supported the panels..... from there, he constructed the legs ect. to the deck. Needless to say, it worked for him as his vertical legs were basically straight....mine will have bends and angles. Thanks!