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Random Quote: Everything on your boat is broken...you just don't know it yet.
Well after almost 1,000 hours of boat busting treament I found a broken pipe on the starvoard cross member. The weld held up fine, the crack is in the pipe next to the weld. I figure that part of the pipe is the weakest link given the heat generated during the welding process.
Anyhoo, what are the next steps I should see happen? I am not doing the welding but want to make certain those that are do the right thing. Thanks in advance.
Your assumptions about the weld are correct. The weld is the strongest part of the pipe. The adjacent material is the weakest, and where the cracks will occur.
Mine cracked in the same place. Problem is, it was in a pipe full of wiring. In fact, the pipe cracked, and shorted/broke some of the wiring.
If your broken pipe happens to have wiring in it, the wiring is in jeopardy. Any welding on the pipe will surely ruin the wires within. Hence, you will need welding, and rewiring. (Assuming you have wiring to the Top of the T-Top)
If there is no wiring, the a competent aluminum welder can weld the crack and make the weld good as new. Except, it will crack again eventually adjacent to the new weld.
Sometimes the welder/fabricator can cut the pipe, insert a internal sleeve, and weld this in as reinforcement. The problem with this is that getting the sleeve inside without removing the top, and prying the T-Top/cracking other pipes, is problematic.
You should be able to have someone weld the pipe and repair it for under $100 bucks. The setup and prep for my work took more time than the fabricator took to weld the joint. (5min)
Please check the other upright posts around your top. I found cracks in the other rear support. If you have one pipe cracked, the others are likely fractured, or soon to crack. Have the fabricator weld/reinforce all other cracks.
For the record, my weld is perfect. Problem is, several more times offshore, and I now have a new crack under the original weld repair. I'm all in for a new T-Top later this month. (Crap)
I can't be optomistic your repair will last. The weld will be fine, but the metal in the pipe is fatigued, and will eventually fail in another place. (My top is 25 yrs old--the roughness of your offshore rides also plays in addition to age)
I hope you broke in a pipe where there are no wires.
BTW, when it cracks after this repair, and you decide to get a new T-Top, you can temporarily bolster the fracture with external splints. I went to Lowes and purchased a strip of 1/4" aluminum that was about three or four feet long. The strip is about 3/4" or 1" wide. I hacksawed a bunch of six inch strips. Purchase some 2 1/2 " Stainless 1/4" bolts with some locknuts.
Drill holes above and below the fracture. Bolt the strip to the pipes using the bolts. I was able to get three or so strips across the fracture. In orthopedics, this is called fracture reduction with external fixation. It is admittedly half a$$ed, but typical for the way I operate. It also allows me to use my boat until my fabricator can get my T-Top into the hospital for replacement.
I don't want to be offshore, pitching the waves, with a fractured T Top flying around the helm in an open ocean!!!!
Don't do the external bolstering with drill holes if you plan on just a weld repair. The additional holes will only further weaken you pipes, and make subsequent fracture even more likely. Only do this after you've decided to junk your frame.
make sure your deck is protected from the sparks and molten stuff.... I have two marks burned into my deck after the repair to my T Top. Grrrrrrrrr....
__________________ Kencraft Buxton 25 PH
Jones Brothers Cape Fisherman CC
Pro line 251 WA
Thanks for the extensive advice dssmith. I'll have the welders do a detailed inspection on any other weld that may be compromised. Luckily the wiring is not in that leg. Fountain builds lots of support points and cross MEMBERS (I said it again mist - ). Hopefully this is an isolated event and fixing it properly will be all that is necessary over the long haul. Attached is a pic of the t-top (port side) and the pipe that broke is the top horizontal cross support (starboard side).
A cross member should be an easy fix. Ask your fabricator about cutting out the cross member near each end and removing the section. Then it would be easy for him to run an inner support pipe that might fit inside the crosspiece. He could then spotweld/reinforce the crosspiece with a weld inside, and then place the original piece (Or a brand new section of pipe) back in place.
From the look of your engineering, you likely just had a flawed piece with the initial fabrication, or the original weld was just too hot. My boat is an old beater. Your top should hold together for many more years before the metal ages and fatigues. 1000 hrs should be nothing. (Unless you are peeing blood after each trip from boat abuse and pounding)
You'd incur the expense of two welds, rather than one, but this might add support and make a more solid fix. Shouldn't cost hardly any more.
The advice about preparing the work area to avoid gelcoat burns is something I never thought about and is excellent advice.
I'm speculating here, and your welder will know if this is worth it or not. I only add this so you can be informed, in advance, of possibilities.
My guy was able to weld in a short inner strut on my job and it doesn't show from the outside. I was even able to run wire back though the spot and get juice back to my T Top.
You are fortunate there is no wiring involved. (More hassle)
That's a nice looking boat, meant to be run. Hopefully you just had a weak piece during fabrication. Just don't run it hard until the top is fixed. Mine will be a harbor boat now until it's fixed up with new stuff.
It sounds like you’re describing a typical fatigue failure. I could see 1000 hours of use beginning to approach the fatigue limit for some of the higher stressed components in your top.
Fatigue in aluminum is similar to other materials, but with aluminum the allowable stresses are lower and you have to deal with the heat affected zone. For instance, a fillet weld (detail cat. F, fatigue design detail 18 for anyone checking my calcs) will have fatigue stress limit of 3400psi for 1mil cycles of constant amplitude stress loading (back & forth rocking due to wave action). Compare this to the allowable of 6500psi for compression of 6063 in the HAZ and you’ll have an idea of how fatigue affects aluminum.
Welding heat also affects the aluminum in the Heat Affected Zone near the weld. Here is some information I posted on the subject last fall:
The inner pipe idea sounds like a good one. It’ll add more area to the joint. Since the unit of stress is psi, adding more square inches to the cross section in the heat affected zone will decrease the stress at that location. Adding an external sleeve could help more, but it probably wouldn’t make that much of a difference. It would depend on the joint geometry and how force is transferred through the joint (i.e. bending, axial, etc..) After the broken joint is fixed, I would monitor other similar joints for the formation of cracks so you can make repairs before the joint completely fails.
If the problem is indeed fatigue related, you may want to look into lightening the load in your top. Since the forces that caused the crack are likely the result of the lateral acceleration of the mass, reducing the mass by removing unnecessary items from your electronics box or not running hard with a lot of rods up top could reduce the stresses in the top enough to prevent future cracks.
Trey ........ what can I say other than "dam", that was a nice healthy serving of information and data. Good news is I talked to the welders and they said they wanted to inspect all of the t-top before they jumped at simply closing the break. I liked what I heard.
Bull ........ I hear you buddy. The economics break down when I start factoring in the $20k in annual airline charges to get to that fishing mecca.
I have a similar crack, but there are wires running through the pipe. Can I save some money if I prep the repair by pulling the wires? Can I tie them with a clothes hanger or something , so I can pull them back through when finished welding?
I pulled my wires, had a weld made, and then refished the wires. Just like you described.
I'd check with the welder about leaving a fishtape or coat hanger in the pipe. Hate to have it become fused in there.
The hassle and expense of the wiring was a) cutting all 8 wires b) labeling them for appropirate reconnections c) trip to Boaters World (again) for butt connectors of appropriate sizes d) rethreading the wires back through the pipe e) splicing the wires with the butt/squash connectors f) retucking the wires and fixing them so they don't shake out in the open.
I did not fish completely new wiring from the T-Top. I just interrupted the wiring and spliced and fished the spliced wires back down the original pipe. Felt pretty good about my work
Real Proud of myself
Then this season the crack formed under the new weld!!!!!
After re-reading my post it may have been a little too much info. But, if it helps you learn why it cracked, then you may be able to have it repaired and you may be able to modify your setup slightly to reduce the chances of it happening again.
If you think the repair won’t last, I’ll be willing to remove the boat and I won’t even charge you a haul off fee.
Let me know how the welder does. I have a few ideas of some modifications I want done to my top and I’ve yet to deal with a pipe welder around Atlanta that I thought did a stellar job.
My welder called today and said they inspected the t-top and only found the one break I found. They thought the rest of the t-top was in fine shape, they even mentioned it is an extremely stout frame. They welded the existing crack and told me to keep an eye on it and all the welds. They don't expect I will have anymore problems with the area they repaired. If something else breaks they will come back and add more bracing if they see a pattern to the problem.
T-top welding repair question 
). Hopefully this is an isolated event and fixing it properly will be all that is necessary over the long haul. Attached is a pic of the t-top (port side) and the pipe that broke is the top horizontal cross support (starboard side). 
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