Advice on a boat hull repair

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Hello list members,I had a boat brought to me to repair and patch some cracked welds on the bottom of the hull.  I did a little research on boat repairs and found that many suggested a patch / rivet approach to hull repairs and others, fiberglass.My first inclination is to weld a patch over the cracked area and I have attached pictures of the job in question.  I also attached the proposed patch design as I don't want to weld at right angles to the direction of the hull metal and form stress points that will crack again.  My drawing is not accurate.  The actual crack runs totally at a 90 degree angle against the grain of the hull.  My patch would have to be somewhat larger than the crack to allow for a gentle curve covering it.In truck or equipment frame repair we always used patches with gentle angles and round ends to avoid sharp 90 degree stress points.  I carry this philosophy to practically every cracked or broken metal joint I encounter be it a bike frame or truck frame.However I am having second thoughts on whether or not welding is the best approach for this project because I am only equipped with a TIG and this calls for a lot of welding.  I am afraid I may put too much heat into the hull and create warpage and more potential problems for myself, not to mention the client.Anyone done large areas on a hull before?  For a welded patch, what thickness metal would be desirable?  The client brought me some 3/16" aluminum plate and while It provides nice strong material to patch with, it is not very flexible and I lean towards a 1/8" plate instead.I plan on grinding the old weld down so I can put a plate over it.  Should I repair the cracks in the repaired weld?  Or just by pass them and count on the patch to be sealed tight?  I usually repair cracks and then plate them but thought I'd ask other people's opinions on this.Apparently the hull was cracked when my client bought the boat and didn't see that it had a large crack in it from hitting something hard.  A boat repair yard did the welded repair and now it is being brought to me because that repair cracked.  Besides not trusting them with the repair, they took three months to get it back to him and he wants it back quickly.Anyone have any thoughts on this repair?Thanks,Tony Attached ImagesLast edited by therrera; 07-18-2011 at 01:09 AM.Reason: to ask another question and clarify the problem
Reply:Man, looks like you have your work cut out for you. I can't imagine why a pretty weld like that would fail? 3 months wait for that? Looks like this vessel has seen better days for sure. Perhaps its time to let it go the way of all things.Good luck. I am looking forward to seeing your solution and its progress though. Sorry I have no useful information to lend.Eric"You're going to need a bigger boat." Chief Brody
Reply:there looks to be alot more weld going down the keel of the boat( middle), that doesnt look factory, are there any other damaged and repaired places, how big is this boat?Of all the things I lost I miss my mind the most...I know just enough about everything to be dangerous......You cant cure stupid..only kill it...
Reply:You know the first thing I would do.... I would advise the boat owner to look into the companies licensing and repair certifications(if they have any at all) Much of the boating repair and service industry goes totally unregulated allowing anyone with a piece of cardboard and majic marker to make a sign that says certified boat repair. If they have a license...I would call the state attorney genreal's office and report them... this repair is criminal and should be reported.   And as another posted mentioned the weld along the keel is not a factory weld and will fail... if not today, perhaps tomorrow.
Reply:Here's what I would personally do If i decided I wanted to do it. I don't know how well this method applies to this particular boat w/o really seeing it though.Completely grind out the cracks, Use a marine alloy like 5052 for a backing plate "patch" and fill in a full pen weld using an appropriate marine alloy like 5356 filler. I would use an argon/helium mixture to greatly aid in the huge heatsink that the hull is (and preheat initially if required). I'm not a boat repair expert by any means, but this is how I would go about it.Welding/Fab Pics: www.UtahWeld.com
Reply:Ive welded for 60 years and after the first repair on a tempered rivited aluminum boat Ive turned them all down. The only way to fix that kind of damage is generaly unexceptable to the person that owns the boat. Its kind of comparable to fiberglassing over a hole in a wooden boat. Temporary and not good.  Mac
Reply:I turn down boats, to much of a hassle as the aluminum has already work hardened beyond the point of no return , once ya weld it the crack moves to the haz, normally in my experience its just not worth it and by the time they pay me they could go buy a new boat ....You could go "Red Green" and use some duct tape and lots of it.I forgot how to change this.
Reply:The rivetted patch is looking better and better...Tim
Reply:as mentioned above the 3M 5200 is an excellent product  and as the poster mentioned coat the inside of the hull in the areas of damage  then slap on a sheet of alum. it will make the repair permanent... and no welding involved,
Reply:Are we talking a big boat or a crick john boat? I have welded a lot of duck'in boats for the farmers around here and I either remove the entire bad section and replace with a circle if I can, or sand the existing welds down and reweld over them. I reweld by making my welds, and sanding them down, weld, sand, weld, sand, weld. This makes for a very long process, but if there is anything in the aluminum, it is going to give you a nightmare to get it out since your tungsten will be blowing more black stuff then my buddies beater truck. I normally repair with a little thicker then what is there. IE 13 ga instead of 14 ga. Also, about joint design, many tanker trailers have a lot of gusset work on them and if you can see one, they finish their welds by running the weld away from the gusset as an run off. That way there is less stress for cracking.I don't mean to jack your thread if I do, but I have an important question that you would like the answer to as well. What does everyone use for an aluminum cleaner? I went to an aluminum conference and everyone said don't use muradic but no one would tell me what is best to use though. That is from cleaner manufacturers, btw. I have tried out a lot of them, but I wanted to know if people liked some over others for different reasons.
Reply:Hi all,thanks for your input on this.  I lean towards a non welding solution after considering the type of damage, construction of the boat and the obstacles involved.First the boat is foam filled.  This is why the repair shop had such a hard time fixing it and their weld looks so bad.  The stuff was melting and dripping right into their puddle.  Near the main tear there are two small cracks that were repaired as well and though they cracked you could see that the welder knew how to run good beads.  He must've had a nightmare when trying to seal the main tear and was probably relieved as hell to have it drive out of their shop.Second, the amount of welding I will have to do will for sure warp the hull and may create undue stress on the ribs and other adjoining areas where it is welded.Third, because the tear crosses into the keel, I am concerned that this may not be a good candidate for welding.  I did a little research on some boating sites and found mention that welding is not a good solution to aluminum keel rails as they tend to crack readily again right next to the weld.Fourth, in order to do the patch repair correctly, it needs to be done from the inside.  The factory said that this is their method for patching (welding), from the inside.  This will involve tearing into the boat from topside, removing the seats, panels, floor boards, foam, etc.  A major task if I say so myself and one that I had not anticipated on when I took the job on.I think I will be walking into a trap and will have to bow out of this job.  As roadkillbobb mentioned, the keel has been welded by a third party.  You can see the shots of the the two rails on either side of the keel  being skip welded.  The original design of the keel looks like that.  You can see where the skip welds were joined by a continuous bead.Attached are a few more shots.  I will offer the owner to repair the smaller ones using a welded patch method and suggest he locate a place that will non-weld a patch for the larger repair.Thanks for your opinions,Tony Attached Images
Reply:Originally Posted by therreraHi all,thanks for your input on this.  I lean towards a non welding solution after considering the type of damage, construction of the boat and the obstacles involved.First the boat is foam filled.  This is why the repair shop had such a hard time fixing it and their weld looks so bad.  The stuff was melting and dripping right into their puddle.  Near the main tear there are two small cracks that were repaired as well and though they cracked you could see that the welder knew how to run good beads.  He must've had a nightmare when trying to seal the main tear and was probably relieved as hell to have it drive out of their shop.Second, the amount of welding I will have to do will for sure warp the hull and may create undue stress on the ribs and other adjoining areas where it is welded.Third, because the tear crosses into the keel, I am concerned that this may not be a good candidate for welding.  I did a little research on some boating sites and found mention that welding is not a good solution to aluminum keel rails as they tend to crack readily again right next to the weld.Fourth, in order to do the patch repair correctly, it needs to be done from the inside.  The factory said that this is their method for patching (welding), from the inside.  This will involve tearing into the boat from topside, removing the seats, panels, floor boards, foam, etc.  A major task if I say so myself and one that I had not anticipated on when I took the job on.I think I will be walking into a trap and will have to bow out of this job.  As roadkillbobb mentioned, the keel has been welded by a third party.  You can see the shots of the the two rails on either side of the keel  being skip welded.  The original design of the keel looks like that.  You can see where the skip welds were joined by a continuous bead.Attached are a few more shots.  I will offer the owner to repair the smaller ones using a welded patch method and suggest he locate a place that will non-weld a patch for the larger repair.Thanks for your opinions,Tony
Reply:gosh! did you hit an iceberg?.. (aaaand i, i will always, looove you,huuuu oh!,,i remember the titanic song..lolhope you get it fixed soon before summer ends..
Reply:Take a pass on this one...That's all you will be doing if you accept......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Quick side note, Winney sang I will always love you for Bodyguard (i think?), Titanic song was Celine Dion, My heart Will Go On. Just sayin.... Carry on gentlemen/ladies! My gut tells me to tell you to listen to zap... That looks like a nightmare project.
Reply:Originally Posted by slow6iMy gut tells me to tell you to listen to zap... That looks like a nightmare project.
Reply:Don't walk away,RUN,
Reply:Do ya think this guy is hard on his boat?  If you touch that you will be the last "f---in A--hole that ripped me off welding this boat"as he continues to beat it into docks banks boats trailers etc etc etc " don't ever take anything to that guy he's a rip off artist" he'll tell everyone in his loudest voice to everyone that will listen. Do you really need that aggravation.If it were my personal boat I would cut it up take out the foam and do it right. But my first preference would be to start with a better boat so it would have to be given to me free. You also my be doing a HUGE favor to other boaters out there by keeping this guy off the water.Miller thunderbolt 250Decastar 135ERecovering tool-o-holic ESAB OAI have been interested or involved in Electrical, Fire Alarm, Auto, Marine, Welding, Electronics ETC to name a just a few. So YES you can own too many tools.
Reply:i would turn down .. to bad, am sure is was a nice boat at one time or  would only repair if boat is turned up-side down AND OWNER assumes ALL RISKs but would cost him big time $$$idealarc 250/250 ac-dc tigidealarc 250/250 ac-dc tig #2 used for sticklincoln sp100hh125dual arbor grinder polisher30 yrs of hand tools52 pitch blocks 6p-26prake gauge -pitch gaugeG&D prop repair 918-207-6938Hulbert,okla 74441
Reply:Originally Posted by slow6iQuick side note, Winney sang I will always love you for Bodyguard (i think?), Titanic song was Celine Dion, My heart Will Go On. Just sayin.... Carry on gentlemen/ladies! My gut tells me to tell you to listen to zap... That looks like a nightmare project.
Reply:Originally Posted by dumb as a stumpDo ya think this guy is hard on his boat?  If you touch that you will be the last "f---in A--hole that ripped me off welding this boat"as he continues to beat it into docks banks boats trailers etc etc etc
Reply:LOL, you are right on  that one slowblow69!...i confused bodyguard with titanic..lolbut your'e correct, celine sang my heart will go on for titanic..i stand corrected...now i'm forced to give up my manhood.lolfyi, i watched the movie titanic several times...i love that movie...especially the part where jack was painting rose's body..lol
Reply:i wouldnt touch that boat with your 10 foot pole.. that boat is an insurance claim waiting to happen, if it wasnt already an insurance claim at one time..tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:Originally Posted by Broccoli1Please report to the Local He Man Woman haters Lodge and turn in your MAN card;Due to 2 girly references and actual knowledge of said Films your MAN privileges have been temporarily revoked!!
Reply:Hi all,for the record, the boat drove out of my driveway this past Monday.  I basically told the owner that the nature of the crack and the fact that it goes into the keel (which is an extruded aluminum piece) makes for a repair that may not hold or may warp or otherwise cause damage to the hull plate, ribs, etc.  I did not feel comfortable putting on such a large patch.I basically said I did not feel comfortable doing it and to take it back to the shop that did the repair work as ultimately they would be responsible for their weld.  He told me that the weld had held for two years and just started leaking this season.Thanks for your help, advice,TonyPS:  I have a doozie of a project that walked in the door.  I started a new thread on it.  It is a cast iron sink that has a chunk missing from the drain.  It was brought to me to make it functional again.   The thread is titled "Depression era cast iron sink repair".   I am interested in getting thoughts from others who may have done something similar.